What are the Benefits of Earthwool Insulation?

York Insulation can Produce upwards of 6-10 degrees difference on jobs where we vacuum the roof and install earthwool R4.0 - Here is why:

• Insulation helps to maintain a uniform temperature, which means the efficiency will improve enough to keep each room closer to the same temperature with far less energy consumption to do it.

• Insulation helps heating & cooling machinery work more efficiently, which means you’ll run lower watts of energy to achieve desired results and you will hold that energy far longer before temperatures shift and the machine turns back on. The shorter run-times and less watts equate to massive reductions on energy usage, which equate to significant reductions in energy costs.

• Insulation can add value to residential, commercial and industrial properties.

• Insulation reduces structural vibration and buffers soundwaves, which means you’re less likely to be bothered by planes, trains, traffic, trades, neighbours or otherwise. It absorbs sound to a noticeable degree of change, which offers far better protection from a noisy world, and far more privacy in a country where homes are built far too close for comfort or convenience.

• Insulates water pipes; when Double Layer options are purchased (See below).

• Insulation regulates home temperature while you sleep so you’re not fighting against the home to stay comfortable throughout the night.

• Improves health & breathing; roof cavities are vacuumed with high powered suction prior to installing new materials, so the dust isn’t sealed within the roof underneath your new insulation. Clients who already had dust, asthma or other lung concerns have only ever reported the change as positive afterwards.

• Reduces aches and pains; in elderly and in those with varying injuries and/or conditions there is often noticeable improvements to comfort reported following installation of new materials.

• Insulation can help keep the home much safer to occupy during a heatwave.

• Keeps your pets more comfortable when left inside the home.

• Reduces greatly the cost of working comfortably from home.

• Creates the feel of a brand new home for a fraction the cost of most kitchen & bathroom renovations.

• The primary feedback from clients is the DEEP REGRET in not having made this investment sooner. Many of our clients receive their first year worth of quarterly bills following installation, and then start researching the weather to draw comparisons in usage. Most clients who track and monitor their usage sharply express regret in their prioritising home aesthetics over home function, as home function can help pay for home aesthetics. In other words you’re better starting your projects with comfort to create the savings to pay for your fancy kitchens, bathrooms and BBQ pits.

The amount of energy you conserve will depend on several factors including the size, layout, position, and construction methods used to build your homes &/or structures; the living habits of individuals &/or employees &/or machinery and equipment in operation, the type and efficiency of the heating and cooling systems being used, materials used in construction and the type of energy/fuel you use to cool or heat your home/structure. 

How Earthwool Insulation Batts Work

The insulation products we use most are glasswool (fibreglass) batts, specifically the Earthwool brand made by Knauf, so that is the product we'll be talking about. We do use other products for commercial and industrial applications, however we’ll speak mostly of batts because they make up the bulk of insulation sales in Australia, and this education is primarily aimed at you, the home owner.

Earthwool batts are nothing more than fine glass fibres layered into what essentially looks like a big soft sponge or "batt". These batts are made up of millions of fibres, layered until the thickness and density give the labelled R-value for each product. Those layers create a huge number of air pockets, which help reduce energy transfer from one space to another. The air captured in the batt is an effective insulator because still air has almost no convection. The batt also has low conduction, which means the material itself does not transfer heat easily when it touches other materials.

In a hot Australian roof the cavity goes positive from heat expansion, and will push air through gaps, lights and a loosely filled batt. A dense, continuous batt and a clean, still cavity are what stop that loop. No Gaps.

Air moving through the batt is not how the batt works — it is how performance is lost. The type of material still matters: some materials pick up heat faster than others, and density and fibre-count are not the same in every brand. For example: polyester is a different fibre and, at the same thickness, is often a lower-density batt — so it usually will not match a denser glasswool batt inside a hot roof.

Insulation resists heat flow in winter the same way it does in summer. Cold climates often need more R-value because the temperature difference between inside and outside is larger for longer, not because cold air “radiates more easily.” This is often what is taught in cold climates, but isn’t the correct information. Radiation is not molecules squeezing through cracks. Cold air is denser; heat expands and cold contracts. That shows up as buoyancy and leakage.

That is why people in homes raised on piers feel a draft through the floor in winter and barely notice it in summer. In winter the air under the house is colder and the pressure difference pulls hard through every gap. In summer that drive is weaker. That is leakage — which is why underfloor insulation and sealing both matter.

Why Earthwool Batts For Walls/Ceilings?

• NO Added Formaldehyde.

  • No carcinogenic HCHO added).

  • Most other markets have moved away from added formaldehyde in residential glasswool binders.

• NO Phenol-Formaldehyde Binders.

  • Knauf ECOSE Binder is plant-based without added formaldehyde.

  • Softer than other glasswool products & itch free.

• NO Colour Dyes.

  • The signature ‘Brown’ is their ECOSE technology.

• Glasswool (Fibreglass) Batts Are A Denser Material that resists energy changes/transfer greater than Polyester products of the same R-value.

  • Thinner Fibres = Higher Fibre Density = More Air Pockets = Greater Performance from the same R-Value.

    • Physics

• More Tensile Strength / Durability when handling.

  • Any installer will tell you it’s harder to cut and tear Earthwool as opposed to other Glasswool/Fibreglass insulation. This is due to its density of fibres being greater.

• Far Greater Resistance to Extreme Roof Temperatures than competing brands.

  • Due to fibre density being greater.

• Greater Resistance to Ambient Moisture.

  • This is important in a country where kitchen and shower fans feed steam directly into the roof cavity. Thinner fibres ‘wick’ or allow evaporation easier, but a soaked batt is still a dead batt. Earthwool is simply more resistant to ambient moisture, nothing more.

• 50 Years Manufacturer’s Warrantee.

  • When the batts aren’t compromised from moisture, dust & other contaminants or compression.

Why Polyfloor By Australian Polyester Solutions For Underfloor Insulation?

• Does NOT Degrade in Atmospheric Moisture Or From Spills Draining Through Floorboards.

  • Material will drain, dry &/or wick moisture / condensation to dry wet areas.

  • Spills pour right through the insulation without damage or rot, and then the aforementioned occurs for a dry end result.

• Stops The Updraft Through The Floorboards

  • Improves thermal efficiency.

  • Reduces moisture & keeps the home feeling much drier.

• Material Fibres are Hollow w/ Microscopic Holes for Added Performance.

  • This means the insulation fibres themselves create air-pockets for further stagnation of air, which helps Polyfloor to perform a lot better than solid fibre Polyester products carrying the same R-value.

• Does NOT Require Water Vapour Barrier.

  • Keeps installation costs down.

  • NOTE: Not a waterproofing system, if your underfloor space is very wet you still need to approach drainage and/or ventilation after installation.

• Does NOT Require Strapping.

  • Keeps installation costs down.

  • Industrial staples penetrate 12mm into the sidewalls of joists every 100mm, and they do not pull out without considerable force.

• Does NOT Wind-wash.

  • No need to worry about exposure to high wind areas.

• Can Be Installed/Retrofitted As Low As 500mm.

  • 4x Bricks or more on your piers.

• 70 Years Manufacturer’s Warranty.

  • When the batts aren’t physically pulled/damaged, nested in by rats/possums or ripped down from your dog enjoying their new chew toy (Dogs LOVE Polyester fibres in their teeth).

  • To avoid rodents it is always recommended you ensure the underfloor space is inaccessible via bricks, panelling, cladding, rat wire or other solution, ensure ventilation in the bricks or otherwise is covered with galvanised rat wire, and in case rodents enter the underfloor space do not have your storage, shelving or otherwise offering an easy way to climb to their new home.

  • The product claims insect and rodent resistant, which is true, until burrowing into it is the best option for the rodent, and if access is granted, they will accept the invitation.

How Important Is Insulation In Warm Climates?

Just as important as in a cold climate.

Heat through an empty roof will cook the house the same way an empty roof will freeze one. The code treating it as optional does not change the physics.

Warm regions still treat insulation as optional because the code lets them, and because heat is treated as an air-con problem. It’s not that builders are doing anything wrong — they’re following the code. Australia’s building codes set the bar low. A lot of inspections are a tick against that bar, not a quality audit of whether the house will actually perform. The market often doesn’t know enough to demand better, or how to avoid the problems those codes bake in, and many of the practices to get the job are where much of the problem lies. Anyone from Europe, Russia or North America can see that a lot of Australian houses are a shell of what a house is meant to be.

Colder climates need more insulation because the temperature difference runs harder for longer. That does not make insulation in the north useless — but a batt in a leaky, wet roof is a lot weaker. Insulation in warm country still needs air-sealing and ventilation. It isn’t only the product. The hole you put it in decides what the product does, and what the rest of the house can do.

Warmer climates also carry more moisture. The coast isn’t dry, and water is one of the things that wrecks houses fastest. Most Australian houses take moisture damage eventually — trusses moving, floorboards pulling, mould, cracked work, uneven floors and walls. A lot of that is moist air coming in through gaps that never got a bead of caulk. That step is cheap. So why isn’t it done?

1. Most trades were never taught to air-seal, or why it matters for comfort and how long the building lasts.

2. For a long time the code was silent on real air-sealing. NCC 2022 moved a bit on energy and condensation. It did not turn volume housing into a blower-door pass. Most production builds still don’t seal like a cold-climate house.

3. Real houses are now called so-called “Passive Homes”, which is a fancy way of saying “built far closer to properly”, but is still not what other nations produce nor is it an excuse to charge what they charge. Volume housing will not spend a day wrapping the house with plywood or waste a bead of caulk unless someone stands over and makes them. Plywood over the frame — the same idea as a BAL-29 wrap-and-board job — is a few thousand in sheet and a day to cut and nail. An apprentice can do this easily. Weather wrap is faster on a hard flat wall than on an open stud and the end result is flush and seamless. Caulk is a few hundred in total for the entire build, and should go on as the house goes up: tedious, not specialist work. These exceedingly basic steps got rebranded as a “passive house” and priced like a luxury package. A real house built closer to properly is not an excuse for that invoice. The missing pieces are cheap and a low-skill crew can fit them without hassle. They aren’t being done because the program and the margin don’t pay for them, not because the materials are exotic.

Whatever the climate or the standard of the build, leaving raw envelope uninsulated is a poor decision. Every part of the house works better with insulation, and the insulation works better when you can’t see sunlight or feel moisture in the cavity spaces — among the other things that still don’t get done here.

What Is Air-Sealing & How Important Is It?

Air-sealing means the house is not a bag of leaks. Air should not wander in and out through random gaps. That does not mean you trap the house with no air change. A sealed house has to control air in as tightly as it controls air out. Planned intake, planned exhaust, moisture taken out on purpose. A dehumidifier on the incoming air (or a proper ventilation unit that dries as it swaps air) keeps the house dry. The rest of the moisture is guided out. That is the opposite of a whirlybird on a hot roof without a wrap and seals, which dumps air and then replaces it with whatever gets sucked through the gutter-line, lights, eaves, ceiling fans and other breaches in the ceiling that are also not being glued.

The product used most on the gaps themselves is caulk: wood to wood, wood to concrete, window to stud — anywhere air will find an avenue to move through. Air carries moisture. Moisture will age a house decades faster than a dry, still frame.

This step belongs before the insulation goes in — while the frame is getting plywood, sarking, builder’s plastic, a proper wrap, or foam board. Batts need still, dry air in the cavity without light. If you don’t seal, air runs through the wall, into the timber, through the batt, and carries heat and moisture with it. Air moving through the batt is lost performance, not how the batt is meant to work. That moisture gets into everything that isn’t waterproof. A lot of factory treatment on timber is not a lifetime coat once the roof is a furnace. Heat up, cool down, season to season, the timber moves. Wet timber moves more.

A leaky house throws away a large share of what the batt is rated to do. Canadian programs measure that with a blower door test (CGSB-149.10). Their work is why we treat air-sealing as roughly half the job next to the insulation — a site rule backed by that testing culture, not an AS/NZS 4859.1 R-Sticker carrying roughly half of what Canadian standards actually check.

That is before you even argue about R-value. Look at how many Australian houses are tired at twenty years next to houses elsewhere that were weatherproofed and have stood for generations. Sealed and dry versus open and wet is the difference.

Air-sealing is tapes, glues, caulk, wraps, builder’s plastic, expanding foam, gaskets and the like. Every build is a bit different. Ventilation and moisture control sit next to the seal. You cannot trap stale wet air inside. Mould is the obvious result.

A blower-door test tells you whether the leaks are actually closed. A tight, ventilated, moisture-controlled house is what people now market as a “passive home.” Passive House is a branded standard with its own numbers — not just “we ran a fan.” NCC 2022 pushed energy and condensation. It did not make every new house a certified passive house, and it is not the only way to cut bills.

Keep heat, wet and sun off the batt and the product lasts. A hundred years is a hope, not a warranty.

How Do I Know If I Need Insulation?

If your home or structure cannot hold its temperature for long without the heater or air-con running, the building has poor thermal properties and you need insulation. Period.

Meaning: if you set the unit to AUTO and it almost never cuts out, or it only stays off for a short time before it kicks back in, you need insulation. If you have to set the machine many degrees past the temperature you actually want just to get close, you need insulation. A fireplace does not cancel that. With a better envelope you can overheat the house on a modest fire, and the wood stack should last a lot longer than months or weeks.

You would not walk into a blizzard naked. You put clothes on. Clothes are insulation. The house is the same in winter. In summer it is not like a body: more insulation in the roof, walls and floor keeps heat out and the place stays cooler. Insulation slows heat through those surfaces all year. Glass and leaks are a separate problem. You still need a proper job on the roof, walls and floor no matter what the weather does.

Will I Feel A Difference?

You won’t believe you’re even in the same house. You will absolutely feel an enormous difference.

Insulation is everywhere. All life on Earth was designed with its own thermal needs, for all seasons (Christian Family Business). You’ve heard of blubber, fat, fur, warm blooded, darker skin, callused or thick skin, high resting metabolism and the other ways animals stay warmer through biological means.

You’ve also seen how things keep cool in summer: people sweating, animals panting, gular flutter, big thin ears, high skin blood flow, light coat, pale skin, thermal windows like bald areas where high blood flow dumps heat and many more examples.

Look a bit further and you get the clever bit — purposeful behaviours: kangaroos licking their forearms, basking, laying on hot surfaces, huddling, shade, moving at night, fanning, spreading out and more.

Search hard enough and you will find artificial means of thermal controls through intelligent design. A thing they build. Innovation; like burrows, bird nests, beaver lodge, mammals lining their burrow with grass/fur/leaves, bee wax comb as a stored-heat box, weaving mud nests, termite mounds with vents for heat & gas and there’s one example here in Australia we find extraordinary for an insect.

Meat Ants in Australia, otherwise known as Gravel Ants, cover their mounds with pale gravel and light material in summer, darker in winter. They change the surface so the sun is thrown off or soaked up. That is insulation by construction, not by flesh. Same idea as a light roof versus a dark one.

Flesh does it. Behaviour chooses a spot or a posture. Innovation is a structure that keeps doing the job when the animal walks away — mound, burrow, nest, house… insulation batt.

Insulation shows up everywhere in nature, so it should be common sense to treat it as seriously as the footings and the frame. The more of the job you get right, the better the house. A fraction of a degree at night is enough for your body to notice, so the small stuff is still worth doing.

Picture yourself naked in a blizzard, too cold to move. Would you feel a T-shirt? You’d still be freezing — but if I asked for the shirt back, would you hand it over? Now cover every inch, no gaps. That’s the difference between some insulation and none. Scepticism is not a reason to stay naked.

On jobs where we vacuum the roof and install R4.0 Earthwool, we see about 6–10 degrees. That is the result that makes the spend obvious.

A T-shirt is not designed to keep you warm. Earthwool insulation is. Nature got there first. The rest is innovation. You will notice. So will the bank account.

But, I Only Want To Insulate Here/There…

Go back to the blizzard. A T-shirt on the chest and nothing on the arms is not getting dressed. Hair on your arms is not sleeves. Carpet on the floor is not underfloor insulation.

People tell us the carpeted rooms are ‘fine’. The carpet is lying on a few millimetres of breathable foam. Even a thick rubber underlay will never come close to the performance of an underfloor batt, and does almost nothing to stop heat moving through the floor. Carpet only feels warmer because the fibres are in contact with a warm blooded foot, so it may be helping to insulate the sole when in contact with it, which obviously feels much better than the bite of a hard floor, but it’s doing next to nothing to regulate the temperature of your home. It takes the bite off your feet. That is all. The slab or the subfloor is still leaking, which is why when you turn the heater off the house quickly changes temperature because the floor and the untreated rooms never stopped moving heat.

Same trick with the air-con on one wall. That room feels alright so you only want the “bad” room done. The machine, shaded roof or east facing wall is hiding the problem. A hot garage roof will still push heat through the shared wall into the bedroom, which is why we never agree to skip the garage if it’s attached to the home. A cold, empty ceiling over the hallway will still steal from the one or more rooms you just paid to do.

Heat does not respect the tape line on our quote. Full coverage is the cheaper job over the life of the house. One heater or one unit can then do far more for the home’s overall comfort, and the fully insulated areas can hold or repel far more heat.

Short run times. Less fighting one room against the next. Patchwork costs less on day one and keeps costing you every summer and every winter, because the areas left exposed never quit working against you and your wallet.

We do not do patchwork. Not a strip over the bedrooms and a skip over the hall. Not a half-vac of the roof. The result will not be strong enough to feel when the weather turns, and it will not pay back like a complete ceiling will. We will not put York Insulation on a job we already know is a half-shirt.

Australian houses are full of gaps, shared walls, downlights and rooms that were never sealed. Partial coverage assumes the building is tidy. It isn’t. Coverage without gaps is the only version that matches how these places are actually put together. We’re about the result. The result is the whole ceiling, vacuumed, then insulated. Underfloor spaces and accessible wall cavities are no different.

“She’ll be right, Mate” = “See you later, Mate”.

So, What Is R-Value? 

The “R-value” of a substance is its direct measure of its resistance to transferring energy or heat; R-Values are expressed using the metric units (m2.K/W). Basically, the higher the R-Value the better the resistance for energy transferring from one space to another.

What is 'Total R-Value'?

Total R-Value is the combined R-Value of all insulation materials as well as the materials used in the home's construction; additionally all air spaces are to be included. 

What Affects Total R-Value?

In theory, everything. A home’s Total R-value is the resistance of the whole layer-cake for that part of the house — plaster, batt, wrap, cavity, cladding, and the air films on each side — not a single number made by adding every product on the site. A lot of roofers do this by adding the numbers on the sarking or roof-blanket and then using those numbers to justify lower R-Value for the ceiling than BASIX requires. That’s the mark of an amateur who doesn’t give a damn.

Those layers include wall cavities, cladding, bricks, timber studs, wraps, underlay and plasterboard. Type and thickness of each one feed into how builders and assessors score the house. A NatHERS star rating is a whole-house score. Total R-Value is usually quoted per roof, wall or floor.

In reality the sums get messy, because a lot of things change what that number is worth in a real room:

• Heat through glass, especially single-pane windows.

• Gaps where the batt does not touch the frame.

  • Bridging where the timber or steel itself carries heat past the batt.

• R-Value is tested at 23 °C.

  • A 40 °C, 50 °C or 60 °C roof is not that test, and not all batts will hold performance as temperatures sore in summer.

• Air moving through vents, holes and gaps in the build.

  • That is convection. It is not a rate stamped on the brick, but throws the Total R-Value needle.

• Moisture through unsealed gaps, open vents and whirlybirds.

• Insulation that is already compressed, incorrectly laid, wet or worn out.

• Damage, gaps and poor workmanship.

• Skipped bits: attached garages, overhangs, drop-downs and the “too hard to reach” corners.

• Sun, aspect and the site around the house.

Once you stack competing brands, different products and the way Australian houses are actually put together, it is more than slapping the cheapest bag with the highest R-Rating in the ceiling. The number on the bag is the starting guide. The house is the test.

Get someone who will walk you through these considerations and provide you with an honest order of trades to ensure the best finish for yourself before you agree to dates and pay the deposit.

What R-Value Does York Insulation Recommend for Australia?

NCC 2022 and NSW BASIX / 7-star tickets raised the paper standard. They did not close every hole available to builders to cut their own costs. Deemed-to-satisfy (DTS) tables still let a builder pick a lower batt on a ceiling, a wall or an underfloor where the row, the model or the ticket allows it. A NatHERS run can trade glass and roof against the wall. A DTS wall table in climate zone 5 can still show well under R2.5. That is how a crew still puts an R2.0 batt in a 90 mm stud, a single skinny layer on the ceiling, or nothing much under the floor, and calls it legal. The ticket is a house score. It is not a tested Total R-value for that plane on a 35 °C afternoon. Most crews who put their name on the job will not install the cheap option. Neither will we.

CEILINGS

Your homes are all very different, but be assured no matter the structure if you apply a minimum standard of R4.0 for any ceiling then you will see great results. This recommendation does not account for and should not include the combined R-values of other things like sarking, roof blanket, foam panelling, plywood in fire danger areas, etc. The ceiling itself should receive R4.0. That is the batts on the plaster — not the rest of the roof added on and sold as a higher R-value.

However, for optimal performance in temperatures exceeding 35°C we insist there is often need for no less than R-value 6.0, preferably comprised of two layers. The industry calls this two layer system “Cross Hatching”, but it confuses customers so we say “Double-Layer” (see Double-Layer section below).

Basically, the height of the joists determines the R-value that can be properly housed between them. Fibres in all batts lay horizontally, and so the batts are designed to stagnate the air from the facing side of the batts, which is why all packages say to tuck the batts into the joists to create a mounded look. Every inch above the joist is money wasted on days above 35°C. The reason for this is the exposed sidewall allows air to penetrate deep into the batt with ease, so you lose much of the performance the expensive R5.0 batts or higher R-Value paid for to protect you from. The part of an R5.0 that stands up above a 90 mm joist is the bit a hot roof can wash. Most manufacturers would rather sell higher R-value than two layers of a lower one, claiming the top layer compressed the bottom. Installers argued the aforementioned as well as the fact that the second layer is laid perpendicular to the joists, which supports most of their weight; hence the industry term “cross-hatching”. Two layers of R3.5 gets you closer to a true R7.0 reading with the negatives of the hot joists taken out of the Total R-value equation, and they only cost about $200–$300 more per 100m2 than R5.0 on its own, which towers over a 90mm joist. This means you get better performance when you don’t need it most of the year, and when you do need it (35°C or higher), it fails to deliver much more than R4.0.

Knauf ran the numbers and ultimately accepted this was not a conspiracy theory and in the end they launched a new R7.0 and R8.0 batt designed wider than the normal standard joist spacing to ensure an overlap to account for what serious installers always knew to be true for Australian roof cavities.

However, unless your roof is pitched high and isn’t completely loaded with trusses, wires and piping and other obstacles, the fitting of batts that thick is a nightmare. Even the professionals don’t like these batts when the roof is cluttered, and they cost a lot of money for our clients. Access to the roof afterwards is a lot harder to move batts to find your footing when the batt needed intricate cuts and fitting to sit correctly to begin with. The reason this is such a difficult install is that the obstacles like pipes, wires, vents, lights and other timber bracing requires cutting the batts, and then the trusses above require that same batt to them be cut to work around the roof trusses. That’s a lot of fighting with a batt to expect anyone who doesn’t do this daily to move it and get it back the way the pros left it.

For these reasons most installers still prefer a two layer installation of Double R3.5 or Double R4.0. Double R5.0 or higher is redundant, as the top layer will rest well above the joists and create the same gap between batts over the joists as is found without a second layer. Hiding the gap doesn’t make it go away when the eves are the hottest part of the roof and feed right into it. Sometimes less is more, and more is less… and in this instance a lower R-Value in two layers provides the best bang for buck.

The top layer can be moved and stacked for a path of access to lights, fixtures, units or otherwise. You still get way above the threshold for Australian roof heat to enter via the ceiling, and the savings are obviously even greater when matched against the sticker price of the new R7.0 and R8.0 batts.

Single layer installations in Australia, or “base layer”, is merely a job half done if heat is a bother for your preferences. If the heat doesn’t bother you, R4.0 is plenty and you just run your units on the days it gets uncomfortable. If heat is an issue, no matter what R-Value you have you will wish you had more if it’s not in two layers covering the timbers. Double layered insulation covers all of your ceiling’s timber supports, achieving the best possible coverage and gives greater performance and savings.

Batts hold thickness better than blow-in / loose-fill, which can settle and reduce the product’s performance considerably. Kneel on a batt and you can still squash it — so don’t. Covering the joists eliminates most Thermal Bridging, which is detrimental to your insulation’s performance. (See Thermal Bridging section below).

We recommend a minimum of R5.0 / R6.0+ for any newer / “modern” and/or larger and/or more open planned homes, as well as any home with a low pitched roof. “McMansions” or “Aussie Slap-Togethers” or “Cookie-Cutter Homes” especially, which are significantly less thermally efficient than older builds — often glassier and leakier than an old cottage — and should be done correctly in two layers.

The larger the house, the larger the air volume you are trying to control temperature within. The newer the home, the more thermal deficiencies you have to counter to achieve a respectable outcome. You would think the opposite was true, but we all know “They don’t make em’ like they used to”, and houses in Australia are as much a part of this throw-away society as the device you’re using to read this. More air volume within the home means more wall and ceiling space, more windows and glass, more floor space (if on piers). The more surface area the more space to allow transfer of heat, and the more air volume within the structure the greater your energy usage will be to combat the laws of physics. The larger and more open the structure, the more seriously you need to take your insulation. However, the larger the roof’s air volume, the longer it will take to heat up enough to begin radiating down into the home. Those are two different volumes.

Environment dictates performance, so know the consequences created by your environment before selecting products and/or R-values. Label R-value is a 23 °C comparison. A 60 °C roof is not that test.

WALLS

R2.5 high-density batts only. That is our spec, and it is what most NSW 7-star / BASIX wall tickets are written for. Some DTS rows still allow less. We don’t install that. We recommend you use only High Density Wall Batts, because they’re far more thermally efficient in a 90 mm stud, are more rigid to avoid sagging within the wall over time and have much greater acoustic properties.

Done right, the extra spend comes off later bills. Buy cheap and you pay far more over their lifespan.

UNDERFLOOR

We recommend R2.5 Polyfloor Insulation only. The underfloor rolls are 11m long and are supported over foundational beams and fitted between the floor joists. They do not require strapping and once stapled to the joists they’re basically part of the house and won’t budge, degrade or damage from wind, light or moisture. Granted no dogs or rodents or other trades physically harm the product, it should outlast you and your home with a 70 year manufacturer’s warranty. Polyester isn’t exactly on par with Earthwool performance, but under a damp, open floor, glasswool does not belong.

Some Earthwool is now made with wax coated fibres for underfloor to avoid moisture and rot, but its not going to let water from spills above a wooden floor flow through it without damage like polyester batts will. Glasswool will absorb water like a sponge, turn it to mush, rot and cause mould. Polyester will drain, wick and dry itself without any damage to the batt whatsoever. Wax or no wax on Glasswool fibres, water will ruin it, moisture won’t until it evaporates and until we see what it looks like after 30+ years we won’t put our name to it. Polyester is proven to last we only ever remove and replace what was too thin to be worth the effort. The newer batts are denser and far thicker than the old days. Polyester is what we use because your underfloor is outdoors with the elements, and its your only shot at ticking all considerations in an Australian build. Most serious installers only agree to use polyester for this reason.

Considerations for wiser project investments

With insulation, more is less, and less is more… cost. The decisions you make to try to save and/or cut corners on your investment today will negatively impact your comfort and savings tomorrow.

We appreciate that not everyone has money lying around, but the fact of the matter is that if you don’t buy the best performing materials you won’t save as much and will need to replace them sooner, so cheaper materials are more expensive in the end. If you can’t afford the best right now, we recommend saving until you can.

Remember, not all products are made the same, carry the same material density or thickness regardless of the R-Value stamped on the bags.

Chemical binders matter, density matters, environment matters and strategy matters.

We only use Earthwool in walls & ceilings, and we only use polyester under floors. This entire page rams home the ‘why’, and that’s it. No range, best performing products only.

If your installer has a range of materials and leaves the choice to you, take that as a sign that they’re about the sale not the result; no serious installer hasn’t already decided what works best, why, and swears by it. They should also have an understanding of your overall plans, and have advice for the best order of trades for the best result.

For example: York Insulation will advise anyone getting their entire roof replaced to let us empty debris and batts from the cavity, leave the insulation bags with the roofers, they strip the roof, they load the new insulation bags into the cavity, they install the new roof and then York Insulation comes back to vacuum the mess both trades have made. Bags are already loaded, so no need to open a new roof or risk the ceiling shoving bags up a manhole. No mess to the home, and the best overall possible finish for you the client… no extra charge to come back another day to finish.

Another example: York Insulation often remove insulation and vacuum the roof so a new air-con unit can be installed into a clean cavity space, and then we come back to make sure the new insulation isn’t being crawled over and moved around and not placed back properly, again, best for the client at our own inconvenience for no extra fee.

Yet another example: York Insulation will often remove insulation and vacuum the roof so electricians, plumbers, carpenters or builders can do their jobs safely in a clean workspace. This ensures they’re not so inconvenienced they rush to get out and take the time to do better work for you.

Know your product. Know your trade. Know your project management.

*Otherwise any installer not covering these bases with you simply doesn’t know or doesn’t care, and no matter how much they know, you can’t teach giving a damn.

Can Existing Walls Be Insulated?

Yes, absolutely. Depending on what you can or want to spend there’s a lot of options to be explored.

Access is the main consideration, and the type of build you’re dealing with will dictate which methods are practical. Access is important because we do not install blow-in or loose-fill in walls.

We require access for bulk insulation, or batts, which will hold their position and offer a far longer life-span. Some newer products can be injected for a hard packed finish that won’t sag, but there’s a limit to the types of builds that this is applicable. Due to moisture exposure and ventilation issues in most Australian builds, Double Brick is basically the only safe option in our opinion.

Some of you will do research and find videos of installers drilling holes in the outer walls and injecting loose-fill insulation. Looks awesome, it’s clever and very simple to install without damage or demolition involved. The real limit here is moisture: brick veneer cavities are often lacking a vapour wrap, which means wet brick wicking into the space. You cannot treat an unwrapped Australian wall the same as a wrapped house overseas and expect it to last.

In Australia you have to cut your way into the wall in most cases to see if the wall has even been wrapped so its able to house insulation without absorption being a risk long term.

If there is a vapour wrap, these homes can then be accessed from the interior walls. However, when timber frames are a factor, there are high and low racking supports, which are the horizontal supports connecting all your vertical wall joists. This means a hole drilled between each joist to ensure the gaps for the top, middle and bottom cavity spaces get filled. This leaves enough holes to plaster and paint afterwards to beg the question, ‘why not just remove the wall and install proper high density wall batts?

Typically during extensions and/or renovation projects this is a practical approach because the planned effort and the cost to hang sheets and plaster/paint is already present. If this is not a practical or affordable option for you to plan around, know that concentrating your budget solely on retrofitting the worst wall is more than worth the effort (most often westerly), because protecting even one wall can make a real difference to complement the overall effort.

What is Thermal Bridging?

A thermal bridge, also called a cold bridge or heat bridge, is an area or component of an object which has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer.

In Australia that is a huge issue. Bridging and leaks are two different faults. Bridging is heat through timber, steel, concrete. Leaks are air through gaps. Both wreck the job.

Thermal imaging often shows where the timber is, how hard the windows are working against you, and every crack that lets energy through. Timber lines are bridging. Cracks are air leaks. Glass is a window load, not a bridge through the batt.

When you have nothing underneath tiles and less than 2 inches of roof blanket compressed directly underneath iron sheeting, your blanket becomes a buffer against a surface temperature in direct sunlight of between 50°C and 80°C on a good Australian summer’s day, but it’s not insulating very well on it’s own. We do not recommend adding this R-Value with the ceiling batts, we recommend minimum R4.0 ceiling batts regardless of any roof blanket or sarking foil.

That 50°C–80°C energy radiates down into the roof. We see roof spaces in the 40°C–60°C range in summer. That cavity has no problem heating the materials in the house. Almost every house we enter has significant bridging through the joists.

This generally applies in a ceiling and wall cavities, where the thermal bridges (roof beams) offer an easy path for heat to through the timber into the plaster. Covering the ceiling supports with a secondary or “Top-Up” layer (See “What Is Double Layer?” section below) covers most of the joist bridging, which lets the insulation perform closer to its full capability. The larger the roof, the more roof supports, the more thermal bridging; meaning the larger your home the more need for a Double Layer installation.

Ceiling fans, ceiling roses, vents, unused air ducts, windows and doors are holes and glass — leaks and openings.

Another common example is any unprotected floor raised on piers — unsealed and/or uninsulated. Most or all of that floor is then a cold path, especially timber over open air. That is a very noticeable cold floor. Underfloor insulation such as R2.5 Polyfloor by Australian Polyester Solutions (long rolls, fewer joins) is a great solution to a cold floor. We use this product to keep our Blue Mountains clientele toasty in winter.

To cut a lot of the underfloor leak, this polyester can be covered with insulation sheeting, blueboard or similar to finish the underside and make a stiller cavity (If raised high enough to be able to work reasonably, and only if the floor above is water-tight). Insulation sheeting adds to what the underfloor already does.

Successful people always preach about getting the little things right — the “1%ers” — the bits that add up. Thermal bridging and air-sealing are two of the most important thermal jobs in an Australian house. Thermal bridging is still ignored by most of the industry. Every joist, every wall stud that is covered, every nook and cranny, every crack and crevice that is sealed and/or insulated will give you more from the insulation.

Covering the bridges speeds up how the job pays back. The more you spend on the right materials and the right labour, the sooner it comes off the bills. Cost should be weighed as heavily as your need to save — or more. Go all in with the right strategy and the right installer.

If reducing energy use by 50%–80% sounds good, that is the whole-house package: double-layer ceilings with Earthwool, underfloor Polyester, high density Earthwool in the walls where we can access, and a focus on sealing and covering bridges everywhere possible. That total is not bridging alone. Some homes are built better than others and sit in different conditions, but you will feel the difference when bridging is in the plan. If you ignore it, do not expect that level of saving.

What Is “Double Layer”?

Firstly, a “Double Layer” is the same as what the industry calls “Cross-Hatching”, which describes the second layer being laid perpendicular to the base layer between joists in a ceiling cavity. York Insulation essentially coined the term ‘Double Layer’ so clients would immediately know what we’re talking about, as the second layer is in the name.

The base layer rests between the ceiling joists, same as any standard installation, and rests in contact with the ceiling. All wires and pipes rest over the first layer of insulation, and the second layer is laid over the pipes and wires. The secondary layer, or ‘Double Layer’, is laid tight together to make a grid of batts that face perpendicular (hence ‘cross-hatching’) to the ceiling joists so that they’re more easily covered and are supported by the joists. Covering the joists not only adds R-value and covers most of the joist bridging, it also covers tiny gaps such as two joists with only room for air to fit between. The second layer also protects the first layer from extreme heat, light and moisture exposure; and it insulates your water pipes if they happen to run through the roof cavity. A second layer greatly extends the performance and longevity of your first layer.

With a single layer of R4.0 you will be comfortable all year, except days above roughly 35°C and below 15°C (this varies house to house for a myriad of reasons), so the extra layer is insurance for heat-waves & cold-snaps. The rest of the year R4.0 is plenty. Some people are more sensitive to temperature than others, but most people never notice the extra protection in mild conditions. This investment is like having insurance on the first layer of batts, and added coverage when the whether demands you need it most.

Your roofs are basically ovens. Declared R-value is a 23°C test. A hot joist and a washed sidewall remove much of this performance — the batt does not die at 50 °C, but once the timber is that hot your batts are being cooked on three sides. The wood must be covered, or don’t expect R-values of any amount to help you during heat-waves. R4.0 falls short on the brutal days, but so do higher R-Values (See R-Value Recommendations ABOVE); covering the joists is what we use for those days in addition to ensuring the initial investment is protected from the elements.

Earthwool comes with a 50 year manufacturer’s warranty, but you’d be lucky to surpass 30 with optimal performance with exposure to moisture, extreme heat and a thick layer of dust and other nasties found in Australian roofs. That 30 vs 50 is our field call, not a Knauf figure. Their figure accounts for their testing, our figure accounts for the disgusting roof cavity not accounted for.

Most other countries cover the joists to account for thermal bridging, only they don’t always do it with two layers of batts. Other countries air-seal their structures so they can get away with using loose-fill insulation without it settling into a thinner, dustier pack. However, other countries lay a layer of batts before using loose-fill or blow-in insulation to “top-up” their secondary layer, which fill gaps and adds R-value to create that desired thickness or “double layer”. They do this because they’re honest enough to admit that loose-fill can and will will compress over time. How fast depends on the product and how it was put in, and of course the condition of the roof and whether or not the home vibrates from wind gusts, kids smashing around, rodents, trades accessing the cavity, etc.

Other nations with far higher standards know their loose-fill/blow-in products have no structural rigidity to maintain thickness, so they start by laying proper batts that can hold their shape so the entire job isn’t reliant on gravity not existing. Their roofs also don’t get nearly 60°C or fill with so much dust and debris.

In far greater builds in climates similar to our own it’s beyond overkill to look cool on YouTube, but totally required in Australia if extreme heat is a problem for you or your family.

Why Not Buy Higher R-Values? Others Say I Don’t Need Double Layer.

We often hear clients tell us the competitor, family or friend disagrees with the need for a “double layer”, insisting on a single layer with a higher R-value. This would be true if the joists were tall enough to properly house the outer wall of an R5.0 batt, which towers over a 90mm joist, which is what most of you have in your roofs.

This matters for two reasons. The first is 10% or more of the ceiling is exposed timbers, as wood in its natural state will easily transfer energy. Once the wood matches the extreme heat found in Australian roof temperatures, the exposed joist and the washed sidewall significantly reduce the extra you paid for. [R5.0 is about $600 more per 100m2 than the cost of R4.0]. The batt does not die in extreme hear, but just about every house in Australia has a magical temperature where everything feels like it stops working unless the air-con is turned up to full blast, and even then it’s often not nearly enough.

The second is that insulation fibres are layered horizontally, and are not designed to protect the air penetrating sideways, they are designed to protect head-on. The manufacturers instruct on all packaging to “tuck” the batts into the joists. The correct placement in all insulation instruction images shows the batts tucked into the joists, mounding upwards at the centre. If the batt towers over the joists the heat penetrates almost the entire top 1/3rd of the batt with ease, rendering your R5.0–R6.0 batts severely handicapped from day 1. Add 50°C radiating into the ceiling joists and your “R5.0” is suddenly indistinguishable from R4.0 on a thermal scan. Will R5.0 out-perform R4.0 overall throughout the rest of the year? Yes, when it’s not scorching hot, however you’re not getting true R5.0 performance / value for money, but you’re certainly paying for it.

No 90mm joist properly houses any batt thicker than R4.0, and no batt can or will outperform Double Layer without the wood covered. Two layers of R3.5 will give you closer to R7.0 on paper with the joists covered.

R7.0 for barely a couple hundred more than R5.0 on its own. That’s insane value for money, and the true reason most customer service reps will tell you “Cross Hatching or Double Layer” is somehow a bad idea. They will tell you it “compresses” the bottom layer, but we installers know that’s a load of rubbish, especially when the second layer is laid perpendicular to the first layer, which means they’re supported by the joists, not the batts between them.

The other reason you will likely get told not to do this, is that they make way more money if everyone sells higher R-Values.

Extra materials can be whatever you feel like paying for. We’ve done mostly Double R3.5, but some have gone as far as Double R5.0. Some clients understand the big picture, and that picture is that when facing so many negatives you have to overachieve to make up for them. That means if you live in Australia you need to exceed the standard as a starting point, and go all-in from there depending on what you can or want to afford.

What Is The Greatest Value For Money In Ceilings?

Double Layer R3.5

This option provides a total ceiling resistance of R7.0 with all wood covered to eliminate the vast majority of thermal bridging, and it only costs roughly $200-$300 more than a Single Layer of R5.0 per 100m2.

This is by far our most popular option when exceeding R4.0, and makes your home super resistant to the hottest of roof cavities in the harshest of weather conditions.

R4.0 is the minimal standard for any reputable installer, however when you exceed this with a single layer the R-value costs start to add up quickly. This is especially important to consider when you realise the joists are only 90mm tall and leave the top 1/3 or more of the batt exposed. In extreme heat the majority of your added performance is lost in higher R-Values, so without accounting for this fact you will certainly not be getting the value you paid for when you need it most.

Once you go higher than the BASIX requirements, and remove negatives by covering the timber, you further increase efficiency of resistance well beyond your roof’s ability to transfer its energy through it, which is the whole point. Remember, testing is done in 23 degrees, and you need more than their requirements to keep performance in 50 degrees. Think of a graph that rises steeply and then plateaus, that is what happens when you climb the R-Value options. Only, after you cover the wood and exceed R5.0-R6.0 in doing so, you will see almost no further improvement with additional R-Value; unless your roof somehow got much hotter than any cavity temperatures being recorded presently.

Environment determines performance, and environment is overcome with overkill.

Knauf (Manufacturers of Earthwool) did some testing and their numbers showed once and for all that in high temperatures R5.0 & R6.0 batts were losing much of their performance from the side of the batts being exposed by towering over a 90mm joist.

York Insulation cannot thank the team at Knauf enough for doing this, as it was a huge step in recognising the importance of gathering real world data from real world environments, and for settling a once ‘heated’ debate between serious installers and Knauf’s competing industry giants.

• Australia’s serious installers have recommended double layer installs for years knowing what actually happens in a real world environment vs. what happens in the lab, regardless of what the data claimed, and Knauf’s findings showed that we were right to criticise Australia’s Insulation Product Testing Standard for hiding it’s data above 23 degrees.

• If you go to York Insulation’s Facebook page you will find a photo of our founder, Jason York, basking in the moment.

• Roof Rats 1 - Degree Qualified Engineers, Experts & Government 0

Knauf ultimately created a new range of R7.0 & R8.0 to be made wider than the standard joist widths to ensure these batts meet to cover the joists and prevent exposure of the batt’s sides.

However, these batts are very thick and can often be difficult to work around pipes, wires, lights, fixtures, trusses and other obstacles like ducting units. For larger roofs with raised pitches that do not have a mess of trusses throughout and/or a myriad of obstacles to work around, this option is just as effective as a double layer of R3.5, only it costs more. When these obstacles exist, even the most experienced installers will struggle to get them installed properly without damaging the batts.

Regardless of these newer extra thick extra wide batts, or a standard double layer, you want to read the section below this one and consider having your local handyman install a walking bridge. The best time to do this would be after we clean & vacuum your roof, and we will simply return on a later date to install. Yes, we will happily come back and split the job at no extra cost to ensure time for other trades to coordinate their efforts so you get the best possible finish.

If you want the extra performance without the walking bridge, the second layer is way easier to move and stack out of the way to create a pathway to access your infrastructure, and is far easier to put back than the thick batts that likely took a lot of effort to get right in the first place.

As installers, we recommend and much prefer the double layer option for all of these reasons, and the ability to mix and match batt direction on the second layer will generally result in a tighter finish.

With R7.0 in two layers of R3.5 you will keep the cost lower than higher R-Values, get a tighter installation with less gaps, and still almost never feel heat above your heads even in heatwaves. The rest of the year the air-con & heating will hardly cross your mind. In winter most clients report not using heaters unless the temperatures drop near freezing.

Accessing The Roof Post Double-Layer Installation;

The only reason we’re ever given when clients reject recommendations for Double-Layer Installations is fear or concerns the roof will be inaccessible following the job. This is true, walking over two layers of insulation and not seeing where to step is a big issue, which is why we recommend a walking bridge be installed prior to works commencing.

These works are for you to source from your local trusted handyman or carpenter.

A Walking Bridge is simply Yellow-tongue boarding installed over the top of the ceiling joists within the roof cavity to create a safe path of access from the manhole down the centre of your roof. These boards will create a path of easy and safe access for all future trades entering your roof, allowing easy access to lights, wires, ducting, water heaters, piping or otherwise.

Once there is a safe path of access, the rest is double layered.

Without this Walking Bridge, the roof can still be accessed any time safely with a double layer installation. All one must do is simply pick up the second layer of batts, which are laid over the joists to make a tight grid/blanket. You can simply peel batts away, stack them neatly to create a path of access in any direction needed, and then put them back on the way out of the roof.

Obviously you don’t want to think about going into a new roof and crawling over your new insulation investment, so we always ask clients to ensure the roof is checked prior to works being carried out to ensure ducting systems are recently serviced, lights and wires upgraded if required or any other internal works needing to be done, so after we finish, the cavity space can be left undisturbed.

This is best completed after the roof is cleaned, so that other trades have a safer workspace free of harmful dust and contaminants. Then we return, no extra charge for splitting the bill and coming back when the roof is ready for us.

If you care enough to choose double layer you might as well care about the safety of your roof and anyone that enters it afterwards.

Is My Old Insulation &/Or Roof Cavity Risking Air Quality And Health In The Home? 

Not always the batt. Almost always the hole it sits in.

A batt that is still in one piece is not automatically a health problem. A filthy, unsealed Australian roof cavity is. Most houses we open have decades of fine dust, exhaust, debris and whatever old trades left on the plaster. The house leaks like a sieve. Heat builds pressure. That pressure pushes air — and that dust — down through lights, vents and the manhole into the rooms you live in. The insulation is one load. The cavity, the leaks and a weak or missing vac are the rest. That combination is in most houses. That is the risk..

Many people assume that by simply having insulation this automatically equates to having good insulation, not realising their materials are far more likely to be of poor quality, and are in no way surviving the roof they were left in.

Most roofs we open in Australia, the insulation has been reduced to an ineffective state and/or has broken down to dust, but it’s not just the insulation you should be worried about. Australian roofs are the dirtiest we’ve ever seen, and in most cases the cavity is a health hazard on its own.

Almost no homes in Australia are weather wrapped and/or air-sealed, in fact most are designed to breathe for “ventilation”.

Almost all structures in Australia leak like a sieve, and when they heat up the air expands to create positive pressure, which then pushes small currents of air down into the home; this carries dust with it.

Almost no fans are covered or filtered and most home owners with downlights will notice dust falling from them from time to time. Most clients notice how fast their homes become dusty after cleaning. Almost all moisture ducts blow moisture INTO the roof, not OUT of it. All of these air openings allow dust to pass freely without filtration, and can affect your lungs and breathing and worsen asthma. Fine dust from a dirty cavity is a source of what you can breathe every day, especially if your air-con filtration and/or ducting is poorly serviced or in need of replacement, or when ceiling fans and vents are turned on to create a draft within the roof, as most vents and fans do not push the air out of the home, but into the roof.

We are not your doctor, but old blow-in is very dusty without accounting for the rest of the roof’s contaminants. City roofs can carry lead from paint and car exhaust. Loose-fill asbestos is a known problem from the past, but not all of it has been found. If you suspect it, test it.

If you or a family member has breathing, lung or throat problems — especially if they started or worsened after moving house or after bringing healthy baby’s home from hospital — have the roof inspected by someone who will actually look in the cavity. See a doctor as well.

A website is not a diagnosis, but we do have many clients over our 10 years in business stating their asthma attacks noticeably subsided following a deep clean with our high pressure vacuum rig.

I Was Told They’d Just “Top-Up” The Old Stuff.

We find it humorous that the very same people telling you that you do not need a double layer want to lay new batts over the old disgusting ones. We argue that they’re giving you a Double Layer in doing so, but not a very nice one.

Topping-up a degraded and ineffective base layer full of rodents, faeces, leaves, carcasses, heavy metal dust and other toxins is hardly providing a service. If you hired anyone to clean a filthy home and they spread newspaper to hide the mess and covered the areas of concern with clean towels you’d all throw them out of your homes, so why do so many people actually pay these so-called installers knowing their strategy is to half-arse it?

You’re already breathing the dust in, but when someone installs batts over dust, the dust plumes everywhere and finds its way into the deepest recesses of your home’s interior cavities; and your lungs. We would like to see this practice outlawed, but mostly we don’t want to see any more of you fall for this questionable yet surprisingly common practice. See Vacuum section below.

Why York Insulation Will Not Skip Roof Vacuuming.

The law does not force every insulation job in NSW to empty and vacuum the cavity. We do. That is our rule. No clean, no install. No top-ups. No batts over the dirt. No “She’ll be right, Mate”.

We “Do it right, Mate”.

A dirty roof leaks dust into the house when it heats up or drafts are created. Stirring that dust and laying new batts over it pushes more of it into the home. That is unethical. Australia already leads the world in asthma and lung disease. We will never put our name to adding to that tally.

Your roof breathes outside air. Your Australian homes are basically naked. They collect dirt, faeces, carcasses, car exhaust, leaves, moisture, old plaster, tile grit, lead from paint and smog, and whatever other trades dumped up there. Most Australian houses leak like a sieve. When the roof heats up, the air expands. That pressure finds lights, vents, downlights, fixtures, ducting when holes are present, wall cavities and the manhole. The expanding heat and drafts push a current into the home. Dust goes with it. You can see it on the frames of downlights, the top of trims and cupboards, etc. You breathe it whether anyone “topped up” last year or not. This issue never goes away, it persists until you vacuum it with high pressure. Most people accept the home gets dusty soon after cleaning, this is why.

Laying new batts over that load does not hide it. It stirs it. Then it seals a dirty plane under a clean face and keeps feeding the house with even higher levels every time the roof cooks or a draft is created. Occupants live there after we leave. The more that happens inside a dusty cavity, the worse the air quality is expected to become.

People’s lungs are not a line item. If refusing the dirty job costs us the work, it costs us the work.

If the hose happens across asbestos waste, Safe Work / the asbestos codes want an H-class vacuum (AS/NZS 60335.2.69) with the right filter — not a domestic vac, not a bag on the grass without a container to contain it. That is when it stops being “our rule” and becomes asbestos work. A bonded shard getting sucked up a vacuum hose meets that legal requirement. The 10 m²-style exemptions are about how much sheeting a householder can pull, but that exemption in no way means that “any insulation vac is fine.”

The standards for insulation vacuuming are not written as “every insulation job in NSW must use H14.” That is why nobody gets booked for a fan-forced rig with an uncontained catch-bag on a trailer or lawn. Many of the crews using the fan-forced rigs still slap their HEPA filters on the motor so there’s a visible filter so they can say its “got HEPA”. That is the tell. They know the air should be filtered, but will not put the filter where it would cost them suction and money.

Many of these crews boast about having large numbers of installers, some claiming all are certified, but apparently you still cannot teach giving a damn.

If the hose can pick it up, the vacuum has to contain it!

When that includes asbestos, H-class and H14 are the standard — not a HEPA badge on the vacuum motor. Nobody polices the bulk rigs, so its up to you to give a damn because we’ve established that the crews doing this, clearly don’t. They obviously know the fan-forced rig’s uncontained bag is not good enough, but if you put HEPA within the air-flow, bye bye suction.

• The HEPA on the motor, rather than actually filtering the air-flow, is the proof.

Again, nobody polices the bulk rigs. That does not change what the machine has to be to cover all bases for all work all installers know they will encounter.

^THAT… is why York Insulation walks away from all contracts without a line item for removal & vacuuming!

Our vacuum is a custom Enduro-Vac, rated for that type of work: which pulls all air into a sealed bulker inside a steel box, which is designed to keep the bag off the walls so air-flow is never restricted. It has two stages of filtration, first a Micron filter, then H14; that’s 0.01 micron filtration with 15Hg. That’s enough pressure to collapse an oil drum.

The air intake valves on our boxes can hurt you if you’re careless with them, that’s the suction you want, and that’s how you know our rig is doing the job no other vacuum in Australia can match. However, inferior equipment is unregulated, and the crews using these rigs will still charge what we do, sometimes higher.

Enforcement is a joke. We do not care what that crowd calls “allowed”, nor do we agree with or care what the government calls “safe”.

We care what is right, and so should you.

***Check out our custom Enduro-Vac***

Why You Should Never Hire Crews Using Unfiltered Fan-Forced Vacuums.

You now know what a clean roof takes from the aforementioned, and the legal standards being ignored pretending asbestos doesn’t exist, it does.

You have also just been educated on the standard of vacuum required to cover every potential hazard and actually do a proper job your lungs with appreciate afterwards.

Yet, these fan-vacs are still what most of the industry turns up with instead. Its another example Australian construction copying other countries when other countries build real houses.

A fan blower and a bag on the lawn. No sealed box. No gauge to read. Not enough pressure to move the needle on an Hg gage anyway, especially with a 6”-9” wide hose. No containment. No H-Class certification on the rig, and no chance in hell of getting one. No H14 within the actual air-flow. No filter standard met when coming across the dangers they will come across.

A weak effort for full market rates.

The hose moves fluff and that’s about it. The heavy dust, the dirt and the debris stay on the plaster. Then they lay batts over it and invoice you.

If they knew that was a proper job using a fan-blower, they would not bolt a HEPA badge to the motor fan to “match” our selling point of difference. The dirty air never sees that filter. The catch-bag still breathes into the street. Put H14 in the real airflow and that fan’s ability to move air dies. They know that.

• The HEPA badge is for their quote, not for your house.

That is not a cheaper method. That is choosing not to spend what a real vacuum costs, then charging you as if they did. Occupants get the plume through the manhole, the lights and the vents. Neighbours get the dust trail from their uncontained bag. The crew get to say they vacuumed, and you get to pay their bill for stirring what their fan vacuum couldn’t handle.

They know it is not good enough, that’s why they’ve started buying the same Honda motors to mimic a high-pressure-flow, only their motors are attached directly to a fan-blower, not a certified pressure-maker with 15 Hg, hence the HEPA going on the motor’s fan, not the vacuum.

For all the talk of courses and certification going around, most crews have proven you still cannot teach giving a damn.

Are There Insulation Rebates &/Or Interest-Free Loans Available In NSW?

Yes. Check the official page before you sign anything. Programs move.

NSW Home Energy Saver (open now for the loan; a separate discount is listed as coming later in 2026):

• Zero-interest loan up to $15,000, repay over up to 10 years, household taxable income up to $210,000. Owner-occupiers and landlords. Australian citizen or permanent resident.

• Discount up to $4,000 later in 2026 for households up to $80,000 or eligible concession cards.

• Ceiling insulation is on the eligible list.

• Apply through the state’s chosen lenders (Brighte and Plenti at launch) after you check eligibility on the NSW site: energy.nsw.gov.au/households/grants-rebates/home-energy-saver.

There is no federal insulation rebate on the NSW insulation page as of the last check. The Energy Savings Scheme is a different animal (certificates on some upgrades). Do not assume it is a fat insulation cheque.

Read the loan rules. For ceiling insulation the Home Energy Saver guidelines require an Energy Efficiency Council (EEC) Certified Insulation Installer, an electrical safety check by a licensed electrician, ICANZ-style assessment of what is already in the ceiling, product on the CodeMark register, and minimum R-values by climate zone. That is the ticket. It is not NSW law for a private insulation job you pay for yourself.

Why York Insulation Is No Longer On That Ticket — And Why We Walked.

We were in it. York Insulation was the first Sydney installer through the course and one of the first NSW members. We joined because vacuuming was in the material and we wanted more clean-outs, as our company goal has always been the lower asthma by sounding the alarm on cavity dust and how to adequately remove it, not because we needed a badge to know how to lay a batt safely.

We thought it would be an army of crews exceeding the standard, not normalisation of the same practices we’ve been screaming against for a decade now.

What we were offered was volume work, doing exactly what we preach against. Hundreds of top-ups in hot cavities. No money in the budget for a real empty-and-vac. Labour-only rates that made one proper roof-vac worth more than 3x rushed installs. We were offered 900+ properties to be insulated and they admitted they wanted it in before 30 June so the next year’s money looked bigger. That is how it was put to us, which gave us less than 4 months to get it done.

We looked at that as a suicide-mission, not a safe program raising the standards, which is what “certified” meant to us.

When we said the occupants would eat the dust and we would cook without opening the roofs, which was part of the course training and we had to photograph competency in these areas: the line was: “the government says it is safe, and we are not here to debate it”.

We ARE here to debate it. That is why we left the EEC.

A scheme ticket is not a clean roof. It is not H-class certified as a requirement as it should be. It is not “the house can breathe after we drive off.” It is a date and a headcount for budget renewals. Volume over Quality.

We felt a great level of paranoia over the 2009 problems from the old rebate program — but we noticed the focus was more on not repeating the past while completely ignoring the present issues. Most people were scared of downlights after the rebate, and the overwhelming majority of them have been swapped for new LEDs that don’t overheat and can be covered. Almost nobody is stupid enough to go into a roof without isolating the power, and now most crews worth their salt open the roof to flood natural light and vent out the heat so we’re far less likely to die in it.

Our industry doesn’t have a reputation of falling off roofs like the solar cowboys have earned themselves.. Why? Because we have not had the same volume rebate gravy-train. Hence their requirement for handrails, which sit there for 95% of the job and do nothing because the crew spends the majority of their day inside the roof, not on it.

To us the program creators were covering their bases so another insulation scheme wouldn’t ruin them too, but they ended up creating new problems: crews in closed hot roofs, manholes open, unfiltered fan-vacs with unsealed bags on the lawn (when they’re even budgeted for), new batts over the dirt, vulnerable people moved out for 1 day as if that cancelled the plume created by top-ups, and contracts in the hundreds with short time frames creating the exact same rushed efforts that caused the very same issues they’re clearly trying to avoid.

“Certified” counted a filter-less fan-blower the same as an Enduro-Vac, and coincidentally enough, the vacuum portion of the CII (Certified Insulation Installer) program is not accredited. In our view the vac chapter stays unaccredited because H-class / H14 on a bulk rig would wipe most of their fleet from the program. Volume over Quality.

Recently the P2 respirators were added to their course, but when Jason York took it the word “filter” was mentioned zero times from start to finish. Most of the crews used N95 masks until the program changed to account for proper safety gear. The work that kills lungs is inside the roof, not the handrail on the tile. We appreciate you have to start somewhere, but when you factor in that the EEC board has some of its largest members on it, it raises questions.

Safety talk was mostly about scaffold, handrails, and an electrician where NSW law does not demand that stack before you isolate the board and do the ceiling. On the jobs we saw, those extras stacked. Isolate the board. Do the ceiling. Their ticket wanted more: electrical upgrades nobody asked for, another unwanted smart meter on another house, handrails on single story roofs with photos of the outside of a roof the crew spend less than 5% of the day on.

A $4,000 insulation job became a $9,000 package.

Interest Free doesn’t sound as fun once those add-ons stack the line items, especially when all you wanted was insulation.

Quality crews do one house and go home. Volume crews rush through their days, and start 2nd and sometimes 3rd jobs when the sun is high and the roof is already scorching in the Australian summer, which to us is the opposite of safe.

Zero interest for the homeowner is not free work. Someone eats the finance so the numbers look big before June. How it gets done becomes “not the debate.”

We will not put York Insulation on 900 dwellings so a budget can refresh. The ABC can borrow our reputation again if they want, but we will not lend ours to a top-up.

If you want the loan, use an EEC-certified crew and read what the ticket actually buys. If you want the roof emptied with a real pump, Earthwool, no batts over filth, and a company that will refuse the job rather than load your house — that is us. You pay us. You do not get our name on a scheme that treats vacuuming as optional once the money is allocated.

Check eligibility here: energy.nsw.gov.au. Then decide whether you are buying a rebate or a result.

Are Whirlybirds A Good Investment?

Firstly, when we see other countries using whirlybirds we have to recall that their homes are built to a far higher standard. There is layers to those roofs, they’re insulated and properly ventilated. When moisture backflows or rain splashes into the whirlybird, that moisture finds it’s way OUT of the home. That obviously isn’t possible in Australia, for our roofs are neither properly ventilated, weather-proofed or complete for that matter. They are but a shell of what a home should be.

Although there’s no denying the positive difference felt in summer following installation of whirlybirds, when you have old insulation, because a lot of heat can and will escape. However, they ultimately cause far more harm than good to your home’s infrastructure. Unless your home is metal frame then whirlybirds are structural suicide in Australia, but even still, insulation degrades faster when exposed to moisture, so whirlybirds on homes in Australia are almost never a good idea because you’re essentially paying someone to shave decades off your home’s life. Remember; it’s an over-glorified overpriced shed, not a house.

Australia is the hottest, driest place on Earth, and that makes it’s residents forget that most of the coastal region is actually very humid throughout most of the year; especially when temperatures rise and fall as often as they do during seasonal changes. If your home’s wood has cooked for one too many summers the chemicals treating the timber would have evaporated and your entire structure can now mould, so allowing extra moisture to backflow into a hot warm dark cavity is counterintuitive, and truth be told we’re always shocked when licensed professionals don’t consider what should be common sense when they advise you to put another hole in your roof instead of advising you the insulation in your roof is defective or non-existent.

Many of you experienced the heavy rains of La Nina’ and found out the hard way what can happen without a properly built and ventilated roof. Moisture enters the timber, causing it to expand and contrast when heated and cooled each day and night, because the laws of physics demand that they will. Most roofs in this country after enough years look noticeably warped and do not resemble anything remotely close to being flush, especially in tiled roofs, and moisture damage to the wood is the cause of this common feature of Australian roofs. The more this process happens the faster it will happen.

End of the day; moisture must be vented out and away from the roof and home, and should never be given opportunity to enter the home freely, this is why other countries wisely air-seal the entire home from the outside atmosphere and ensure all internal moisture finds its way out. If your roof is so hot you want to put holes in it, you need new Earthwool insulation.

How Do I Assess My Roof Insulation Needs?

If it’s not Earthwool, and its not newer than 20 years, it belongs in a landfill. If its not Earthwool and its brand new, it still belongs in a landfill. Earthwool is the highest performing Batt by a significant margin in high temperatures and extreme lows, and then there’s a big gap where the rest battle for the title of first loser.

If you have no insulation, you need Earthwool insulation.

How Do I Assess My Underfloor Insulation Needs?

If you’re living on a raised home with a subfloor cavity, you will never get the full value of ceiling insulation without protection from subfloor radiation & convection. Carpet or no carpet the home will never retain heat without Underfloor Insulation. Period. Underfloor insulation also will not work without good ceiling insulation, so for those living off the ground you need both applications to be efficient. They work in tandem.

Walls are obviously important, but scroll back up to our wall recommendations and see if that option is even viable without demolition of the walls for your style of build.

How Do I Get A Quote?

Our “Get Quote” page has a form where you can provide us with your personal details and as much information as can be provided about your project, including photos of spaces to be inspected. In most cases once an address is provided, the measurements can be accurately obtained from the internet via satellite imagery, building software and other programs can also help verify the measurements.

• If measurements and photos can be obtained upfront, we can generate an accurate quotation without leaving the office. If not, then we schedule you into the next “quote day”, where we will dedicate the entire day to visiting as many of you as we can manage.

All we need for underfloor quotations is measurements and photos of the access, as we only use one product for all underfloor applications and so there is no need to size the joists for material orders. As long as there is 500mm clearance at a minimum, we can help you.

Thank you, we hope you found this helpful and look forward to working with you.