By Steve, Director · Ascend Roofing Group · August 2026 · 7 min read
If your upstairs rooms are unbearable by late afternoon, the roof is usually where the problem starts. But "add insulation" covers several different products that solve different parts of it, and they are not interchangeable.
Sarking: the moisture and draught layer
Sarking is a thin reflective membrane laid over the battens before the sheeting. Its main jobs are managing condensation and wind-driven moisture, and adding a reflective barrier.
It is thin, so on its own it contributes relatively little thermal resistance. What it does contribute is control over water that gets past the sheeting — in driving rain, or as condensation on the underside of cold metal.
Anticon: the blanket that does the thermal work
Anticon is a glass-wool blanket bonded to a reflective foil facing, laid over the battens under the sheeting. It combines the reflective layer with genuine thickness, so it does real thermal work and dampens rain noise noticeably.
It comes in different thicknesses with correspondingly different R-values. For a Queensland roof the trade-off is usually between the thermal performance you want and the thickness the roof detail will accommodate.
Ceiling batts: the layer most homes already have
Batts sit on the ceiling, not under the roof. They slow heat moving between the roof space and your rooms, and they are the cheapest way to improve comfort in an existing home because they need no roof access.
They also do nothing to stop the roof space itself becoming an oven, which is why batts alone often disappoint in summer.
What to use together
For a Queensland re-roof, a common and sensible combination is Anticon under the sheeting plus adequate ceiling batts, with ventilation to move hot air out of the roof space.
Anticon slows heat entering the roof space. Batts slow what remains from entering your rooms. Ventilation removes what builds up anyway. Each covers a gap the others leave.
Ventilation is a genuine part of this, not an upsell — see our comparison of whirlybirds and solar roof vents.
Timing: why it matters at replacement
Anticon and sarking go under the sheeting, so the only cheap moment to install them is while the roof is off. Retrofitting later means paying for roof access twice.
If you are already replacing the roof, this is the decision worth spending an extra ten minutes on with your roofer.
A caution on R-values
R-value is a useful comparison number but it describes the product, not your house. Gaps, compression, poor coverage around penetrations and an unventilated roof space will all undercut the number on the packaging.
Installation quality matters as much as the specification.
Common questions
Will Anticon make my roof quieter in rain?
Yes, noticeably. The blanket dampens impact noise, which is the main reason people who move from tile to metal are surprised by how quiet it is.
Can I add Anticon without replacing the roof?
It is installed under the sheeting, so it means lifting the roof. If a replacement is not imminent, ceiling insulation and ventilation are the practical improvements.
Is sarking enough on its own?
For moisture management, often. For summer heat, usually not — it is thin, so it adds little thermal resistance compared with a blanket.
Talk to a licensed Brisbane roofer
Ascend Roofing Group is a family-owned, QBCC-licensed roofing business working across Brisbane, the Gold Coast, Logan, Ipswich and Moreton Bay. Free inspection, written quote, no obligation.
Get a free quote or call 0419 098 049.