Cavity Wall Insulation Brisbane
Cavity wall insulation in Brisbane slows the heat that soaks through brick and block walls on hot afternoons. Insulation Extract injects Knauf Supafil glasswool into suitable existing wall cavities, without demolishing walls or replacing linings.
Extraction & Batts
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Most people think about the roof first, and in Brisbane that is the right starting point. But once the ceiling is insulated, walls become the next big pathway for heat. A west-facing brick wall can absorb sun all afternoon and keep releasing that heat into bedrooms and living rooms well into the night. Filling the empty cavity inside a suitable wall can make those rooms noticeably more comfortable.
What is cavity wall insulation?
Many masonry walls are built with two layers separated by an air gap, or cavity. In older homes that cavity is usually empty. Cavity wall insulation fills it with loose glasswool fibres, blown in through small holes drilled in the mortar joints or internal linings. The fibres settle into a continuous layer that resists heat flow between the outer and inner skins.
Knauf Supafil cavity wall insulation
We install Knauf Supafil, a blown glasswool product designed for existing and new masonry cavity walls.
- Glasswool insulation that is non-combustible to AS1530.1
- Treated to repel water, helping protect against moisture moving across the cavity
- Injected from outside or inside the home, depending on the wall
- Improves thermal and acoustic performance of the wall
- Small injection holes are patched and finished on completion
Because it is blown in, Supafil can fill a cavity around wall ties and minor obstructions that would stop rigid boards or batts from being fitted after construction.
Why wall insulation matters in Brisbane
Afternoon sun on western walls
In Brisbane's climate zone 2, summer afternoons are long and hot. West-facing walls take the brunt of that sun. Masonry stores heat, so without insulation in the cavity, the inner wall heats up and radiates into the room for hours.
Cooling efficiency
When walls and ceilings are both insulated, the air conditioner has less incoming heat to fight. Rooms cool down faster and stay cool longer once the system is turned off.
Cooler winters inland
Winters in Brisbane are mild, but further inland the story changes. Ipswich and the western suburbs can have chilly mornings, and Toowoomba on the Range gets genuinely cold winter nights. In those areas, insulated walls also help keep heating inside the home rather than leaking out through cold masonry.
Noise from busy roads
Insulated cavities can also reduce noise transfer, which can help homes near busy roads, flight paths or railway lines.
Is my Brisbane home suitable?
Brisbane has a wide mix of wall types, and not every wall can take cavity insulation. That is why every job starts with a free on-site assessment.
Masonry walls with a cavity
Walls with a brick or block outer skin and an accessible cavity are the main candidates. We check the cavity width, look for blockages and confirm the construction before recommending an install.
Brick veneer homes
Brick veneer is very common in Brisbane suburbs built from the 1970s onwards. Whether a brick veneer wall is suitable for injected insulation depends on how it was built and what sits in the cavity, so we assess each home individually and explain the options.
Queenslanders and timber homes
Traditional Queenslanders often have single-skin timber walls, with exposed framing on one side and no cavity to fill. Other timber-framed homes are usually insulated with batts when walls are opened during a renovation or re-cladding. For these homes, the roof and subfloor usually offer the best improvements, and we will tell you straight if cavity insulation is not the right fit.
Moisture and condition checks
Before any install, we check for signs of rising damp, leaks, cracked render or damaged mortar. Problems like these should be fixed before a cavity is filled.
How we install cavity wall insulation
- 1
Free assessment
Our specialist inspects your walls, checks construction and cavity condition, and confirms which walls are suitable.
- 2
Drilling
Small holes are drilled in a set pattern, typically in the mortar joints outside or in the internal linings, depending on the wall.
- 3
Injection
Supafil is blown into the cavity under pressure, filling it from bottom to top so there are no voids.
- 4
Patching and finishing
Holes are filled and finished to blend with the surrounding wall as closely as possible.
- 5
Quality check
We check that each wall section has been filled and walk you through the finished job.
Start with the ceiling, then the walls
For the best result in a Brisbane home, we usually recommend making sure the ceiling is well insulated first, since the roof is the largest source of heat gain. We install Knauf Earthwool® ceiling batts, made with up to 80% recycled glass and ECOSE® Technology, a bio-based binder with no added formaldehyde, and backed by a 50-year manufacturer warranty. If your old ceiling insulation is tired, we remove it with our 25HP vacuum straight into sealed truck hoppers first.
Cavity wall insulation across South East Queensland
From our branch at Hemmant, we service Greater Brisbane, Moreton Bay, Logan, the Redland Coast, the Gold Coast, the Sunshine Coast, Ipswich and Toowoomba. Insulation Extract has been operating since 2014, is part of the Energy Efficiency Group and works to ISO 9001, 45001 and 14001 certified systems. Call (07) 3088 6933 to book your free wall assessment.