Insulation batts are pre-cut blankets of glasswool, polyester or rockwool that fit between ceiling joists, wall studs or under floors to slow heat flow. They suit homeowners re-roofing, renovating or fixing a hot, noisy or cold room, and the price depends on the material, the thickness and how hard the roof space is to reach (indicative — get itemised quotes).
This guide compares the main types, explains where each one goes, lists what drives cost and shows how to choose and install insulation batts without costly mistakes.
Key points
- The best insulation is the one that suits the location: batts for ceilings and walls, rigid panels for roofs and sheds, and reflective foil for radiant heat.
- Compare products by their stated R-value, fire behaviour and moisture performance on the manufacturer’s data sheet, not by thickness or brand alone.
- Gaps, compressed batts and covered downlights waste more performance than choosing a slightly cheaper product.
- Old or unknown insulation can contain asbestos, so stop and get it tested before you disturb it.
What are insulation batts?
Insulation batts are flexible, pre-cut sections of fibre insulation sold in widths that match standard joist and stud spacing. They trap air in the fibres, which slows the movement of heat.
Walk into any Sydney roof space in January and you can feel what a missing or patchy layer costs you. A properly fitted layer keeps the house cooler in summer and warmer in winter.
- Material: glasswool, polyester, rockwool, cotton or wool blends, each with different fire, moisture and itch characteristics.
- Thermal rating: shown as an R-value on the pack, where a higher value means better resistance to heat flow.
- Form: batts for ceilings, floors and walls, rolls for loose spans, and rigid boards or panels for roofs, slabs and cladding.
- Colour: pink, yellow, grey or white; colour is a branding choice and says nothing about performance, so ignore white insulation claims.
- Fire and moisture data: check the manufacturer’s data sheet, because noncombustibility and water behaviour differ between products.
- Minimum requirements: the National Construction Code sets minimum thermal performance by climate zone, so confirm what applies to your project.
Types of insulation batts
Different types of insulation suit different jobs, so match the product to the location before you compare prices.
| Type | Best for | Strength / performance | Price band |
|---|---|---|---|
| Glasswool batts (including Bradford Glasswool HD) | Ceilings and walls in most homes | Good thermal value, light and widely available | $$ |
| Polyester batts | Allergy-sensitive households and DIY | Non-itchy and easy to cut, with good acoustic value | $$$ |
| Rockwool / stone wool | Fire-sensitive and noise-sensitive areas | Strong fire and sound performance | $$$ |
| Cotton and wool batts | Eco-focused renovations | Natural fibres with treatments for pests and fire | $$$$ |
| Foil-faced or reflective insulation | Under roof sheets and in sheds | Reflects radiant heat, needs an air gap to work | $–$$ |
| Rigid foam boards and sandwich panels | Roofs, slabs, sheds and wall cladding | High value per thickness and structural options | $$$–$$$$ |
Prices are bands only, so ask for itemised quotes once you know your areas (indicative — get itemised quotes).
Rockwool insulation batts
Rockwool is a dense stone-based batt with strong fire and sound performance. See our Rockwool insulation guide for where it earns its higher price.
Bradford insulation batts
Bradford is one of the best-known Australian ranges, covering ceiling, wall and floor products. Our Bradford insulation guide lays out the line-up, including Bradford ceiling insulation.
Knauf insulation batts
Knauf makes glasswool and other products for roofs and walls. Compare the range in our Knauf insulation guide.
Bradford Gold batts
Bradford Gold is a premium glasswool range aimed at thermal and acoustic performance. Read the Bradford Gold guide before you pay for the upgrade.
Insulation panels for walls, roofs and sandwich panel systems
Rigid panels do jobs that batts can’t, such as forming a roof, lining a slab or insulating a shed without a stud frame.
| Product | Where it goes | Notes |
|---|---|---|
| Expol insulation (expanded polystyrene) | Under slabs, behind cladding, in walls and roofs | Lightweight and low cost, so check fire rating and termite treatment requirements |
| Insulated sandwich panels | Patios, extensions, sheds and cool rooms | Roof and insulation in one product, with steel skins |
| Colorbond insulated wall panels | Garages, workshops and outbuildings | Quick to install, with a steel face and a foam core |
| Roof insulation panels | Between rafters or over purlins | Ideal for cathedral ceilings where batts don’t fit |
| Lightweight insulated ceiling panels | Renovated ceilings and sheds | Finished surface and insulation together |
| Polystyrene wall cladding | External wall systems with a render finish | Specialised installation, so use a licensed applicator |
- Insulated slab: rigid boards or edge insulation under and around a slab cut heat loss from the floor, but need to be designed in before the concrete is poured.
- Insulated sheets: sold under many names, so always check the core type, skin and the data sheet.
- Insulation wall panels: good for garages and studios; interior wall batts suit stud frames and are covered further below.
- Termite and moisture: in some situations foam needs a termite barrier or management plan, so ask your builder or certifier.
- Fire performance: rigid foam and panel cores vary widely; request fire test information for your building class.
- Roof panels: for patios and extensions, see our guide on Anticon roof blanket as one alternative under metal roofing.
Insulation batts cost
Costs are driven by material, thickness, area and access, so use this table to see where money goes, not as a quote.
| Item | Materials only | Installed |
|---|---|---|
| Glasswool ceiling batts | Lowest cost per m² (indicative — get itemised quotes) | Low to mid cost per m² (indicative — get itemised quotes) |
| Polyester ceiling batts | Mid cost per m² (indicative — get itemised quotes) | Mid to high cost per m² (indicative — get itemised quotes) |
| Rockwool batts | Mid to high per m² (indicative — get itemised quotes) | High cost per m² (indicative — get itemised quotes) |
| Wall batts in an existing house | Mid cost per m² (indicative — get itemised quotes) | Often impractical without opening the wall (indicative — get itemised quotes) |
| Floor insulation batts (subfloor) | Mid cost per m² (indicative — get itemised quotes) | Rises with tight crawl spaces (indicative — get itemised quotes) |
| Rigid panels for roofs and sheds | Mid to high per m² (indicative — get itemised quotes) | High cost per m² (indicative — get itemised quotes) |
- Roof space access: a tight cavity or a low-pitch roof slows the job and raises labour.
- Old insulation removal: stripping dusty or damaged material adds labour and disposal, and anything that might be asbestos stops the job until it’s tested.
- Existing wiring and downlights: a licensed electrician may need to move or cover recessed lights with rated covers first.
- Area and layers: a bigger area lowers the unit rate, but a second layer to reach higher ratings adds materials.
- Cheap roof insulation: low-cost rolls often lack proper ratings, so check the label and data sheet before you buy.
- Rebates and programs: state energy-saving schemes change often, so check current NSW offers before you commit.
Pros and cons of insulation batts
| Pros | Cons |
|---|---|
| Fits standard joist and stud spacing without special framing | Gaps and squashed sections cut performance sharply |
| Lower cost than rigid panels for ceilings | Glasswool can irritate skin, eyes and lungs during installation |
| Helps with winter warmth and summer comfort | Not much use against radiant heat from the roof alone |
| Some types reduce noise between rooms and floors | Can hold moisture if the roof leaks or condensation builds |
| Easy to top up with a second layer in most roof spaces | Hard to retrofit into existing walls without opening them up |
| Wide range of brands, including Bradford and Fletcher Pink Batts | Ratings and fire data vary between products, so each one needs checking |
How to choose insulation batts
- Define the location: ceiling, wall, floor, roof or shed all need different products, and the wrong one fails.
- Check your climate zone and the National Construction Code minimum for new work, then aim for at least that level.
- Compare R-values from data sheets, not marketing labels, and consider the installed thickness your space allows.
- Weigh fire and moisture performance, especially in bushfire-prone areas or roof spaces with a history of leaks.
- Think about noise: polyester and rockwool help if you share walls or have a busy road outside.
- Consider who will install it, since DIY suits simple ceilings but not roofs with downlights, flues or wiring.
- Get itemised quotes that list product, rating, area and labour so you can compare like with like.
Installing insulation batts safely
A tidy installation often matters more than the product, and the roof space is hot and awkward.
- Test unknown or old insulation for asbestos before you touch it; loose-fill and old sprayed products may contain asbestos and need a licensed professional.
- Turn off the power at the switchboard if you must work near wiring, and use a licensed electrician for any electrical changes.
- Wear gloves, long sleeves, eye protection and a P2 respirator, as fibres irritate skin and lungs.
- Walk only on the joists or on boards, because stepping between them puts a foot through the ceiling.
- Cut batts to fit snugly without squashing them, and butt joints tight with no gaps.
- Keep batts clear of downlights, flues and exhaust fans unless the product and fitting are rated to be covered.
- Work early in the day in summer, since roof spaces can become dangerously hot.
Wall insulation and insulation battens
Walls lose a surprising amount of heat, but retrofitting is harder than a ceiling job. Our wall insulation guide covers what to expect.
- New builds and gutted rooms: wall batts fit between the studs and give both thermal and sound benefits.
- Existing walls: these usually need cavity work or a lining change, which belongs with a builder rather than a weekend DIY effort.
- Insulation battens: batten insulation is used where a gap is needed behind cladding, so check what a supplier means before you order.
- Moisture control: keep walls dry and vented as directed, since trapped moisture rots framing and grows mould.
- Wiring and plumbing: leave clearances around cables and pipes, and call a licensed electrician or plumber for any changes.
- Termites: keep insulation from bridging termite barriers, and ask your pest inspector before you fill any gap.
Garage door insulation and sheds
A garage door is a big uninsulated panel, and a shed is often a metal box that acts as an oven. Our garage door insulation guide goes through the door options.
- Garage doors: insulated panels or kits cut heat and noise, but they must suit your door’s weight limits and opener.
- Best way to insulate a shed: start with reflective foil under the roof sheets, then add rigid boards or sandwich panels on the walls and ceiling.
- Air gaps: reflective foil only works with an air space facing it, so don’t press it against the roof sheet.
- Ventilation: vent the roof space to limit condensation, which drips back onto stored tools and timber.
- Sealing: close gaps around doors and eaves, because air leaks undo good insulation quickly.
- Wiring: keep any power in conduit installed by a licensed electrician, never loose cable behind foil.
Insulation batts FAQs
What are the different types of insulation?
The main types are glasswool, polyester, rockwool and cotton batts, reflective foil, and rigid foam or sandwich panels. Batts suit ceilings and walls, foil suits radiant heat under metal roofs, and panels suit roofs, sheds and slabs. Pick the type that matches the location, then compare ratings on the data sheets.
What is the best way to insulate a shed?
Start with reflective foil under the roof sheets, then add rigid boards or sandwich panels to the walls and ceiling. Seal gaps, allow ventilation to limit condensation and keep wiring in conduit installed by a licensed electrician. A metal shed with no insulation gets very hot in a Sydney summer.
Are Fletcher Pink Batts better than other brands?
No brand is automatically better. Fletcher Pink Batts, Bradford and Knauf all make glasswool products with stated ratings. Compare the R-value, fire and moisture data and the warranty on each data sheet, then choose the one that fits your space and budget rather than by name.
Can you put insulation batts over old insulation?
Sometimes, if the old layer is dry, undamaged and free of asbestos. Test or inspect anything unknown first. Lay new batts across the old ones rather than in line, avoid compressing either layer and keep clear of downlights and wiring. If the old material is wet or contaminated, remove it first.
Do insulation batts help with noise?
Yes, to a degree. Dense products such as polyester and rockwool reduce sound travel through walls and floors more than basic glasswool. For real noise problems you also need to seal gaps and sometimes change the wall or ceiling lining, because insulation alone won’t stop airborne noise.
Is cotton insulation worth the extra cost?
Cotton and wool batts appeal to buyers who want natural fibres and they perform well when treated for fire and pests. They cost more than glasswool, so they make sense when you value the material, not when you only want the cheapest thermal upgrade.
Getting insulation batts installed in Sydney
A well-fitted layer of insulation batts pays off every summer and winter. TQN Construct’s licensed roofers assess your roof space, test unknown material and fit the right product, with itemised quotes and workmanship cover. Book a free roof inspection and quote.
