Underfloor Insulation Brisbane
Underfloor insulation in Brisbane keeps Queenslanders and other raised timber homes warmer on winter mornings and blocks the draughts that whistle up between the floorboards. Insulation Extract fits Knauf Earthwool® batts, closed-cell spray foam and other underfloor systems to suit your subfloor.
Extraction & Batts
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Raised homes are part of Brisbane's character. Queenslanders on timber stumps, post-war highset homes and many hillside houses all sit above open air. That design helps air move under the house in summer, but it also means the floor is exposed on its underside. With nothing beneath the boards, warmth escapes on cool nights and cold air leaks in through every gap. Insulating underneath is one of the simplest comfort upgrades for an older timber home.
Why underfloor insulation suits Brisbane homes
Queenslanders and highset homes
A classic Queenslander has timber floorboards laid over joists and bearers, sitting on stumps with an open or partly enclosed space underneath. Older boards shrink and gaps open over time. On a July morning in suburbs like Ashgrove, Bardon or Coorparoo, the floor can feel noticeably cold underfoot, and draughts make heating less effective.
Mild winters, but real ones
Brisbane is in climate zone 2, so winters are mild compared with the southern states. Even so, overnight temperatures in the cooler months can drop low enough to make an uninsulated timber floor uncomfortable, especially in western suburbs and around Ipswich, and much more so in Toowoomba.
Year-round benefits
Underfloor insulation is mainly about winter comfort and draught control, but sealing gaps and adding insulation also helps an air-conditioned home hold its temperature in summer, particularly where the space under the house has been partly built in or gets hot.
Underfloor insulation options
Knauf Earthwool® underfloor batts
Batts are fitted snugly between the floor joists and held in place with a support system so they do not sag or fall over time. Earthwool® is made with up to 80% recycled glass and ECOSE® Technology, a bio-based binder with no added formaldehyde, and carries a 50-year manufacturer warranty.
Closed-cell spray foam
Closed-cell polyurethane spray foam is sprayed directly onto the underside of the floor. It expands to seal gaps between boards and around penetrations, providing both insulation and an air seal. It is especially useful where draughts are the main complaint or where joist spacing is irregular.
Panels and polyester rolls
For some subfloors, rigid underfloor panels or polyester rolls are a practical choice. We recommend the product after seeing your subfloor, rather than using a one-size-fits-all approach.
Is my home suitable for underfloor insulation?
Most raised timber homes can be insulated from underneath, as long as there is safe access. We check:
- Crawl space height: we generally need more than 600mm of clearance to work safely and do the job properly, and highset homes usually have plenty
- Access throughout the subfloor, including areas behind lattice, stairs or storage
- The condition of the floorboards, joists and bearers
- Ventilation under the house, which must be maintained to manage moisture
- Plumbing and electrical services running under the floor
Concrete slab homes are a different case, as there is no accessible space under the floor.
Moisture, termites and flood-affected homes
Ventilation and humidity
South East Queensland's humidity means subfloor ventilation is important. Underfloor insulation is installed so that air can still move under the house, and we will point out any moisture problems we see, such as poor drainage or leaking plumbing, before work begins.
Termite inspection access
Termites are a real concern in Brisbane. Before insulating under a raised home, we discuss keeping stumps, bearers and inspection zones accessible so your regular pest inspections can continue.
After floods
Parts of Brisbane, Ipswich and Logan were badly flooded in 2011 and again in 2022. If your subfloor has been inundated, existing insulation may need to be removed. Products and installation details can be chosen with future flood risk in mind, and we can talk you through the options.
Lifted, built-in and renovated Queenslanders
Many Brisbane Queenslanders have been raised and built in underneath to create a lower level of bedrooms, a rumpus room or a granny flat. In these homes the old floor now sits between two living levels. Insulating it is best done while the downstairs ceiling is open during a renovation, and it helps with both temperature and noise between floors. If you are planning a lift and build-in, talk to us early so insulation can be fitted before the new ceiling is lined.
Our underfloor insulation process
- 1
Free assessment
We inspect the subfloor, measure clearances, check the timber and ventilation and recommend the right product.
- 2
Preparation
The work area is cleared and any old, damaged or fallen insulation is removed.
- 3
Installation
Batts are fitted and supported between joists, or spray foam is applied evenly to the underside of the floor, sealing gaps as it goes.
- 4
Quality check
We inspect coverage, support and clearances around services and talk you through the finished result.
Underfloor insulation across South East Queensland
Our Brisbane branch at Hemmant services Greater Brisbane, Moreton Bay, Logan, the Redland Coast, the Gold Coast, the Sunshine Coast, Ipswich and Toowoomba. Insulation Extract has been operating since 2014 as part of the Energy Efficiency Group, with ISO 9001, 45001 and 14001 certified systems and more than 45,000 Australian homes retrofitted. Pair underfloor insulation with ceiling insulation for the biggest improvement. Call (07) 3088 6933 to book your free assessment.
