Skillion roof/cathedral ceiling

Insulating a home with no ceiling space is not as straightforward as in other homes, but it is possible to do. A lot of heat is lost through an uninsulated ceiling so, if you have a skillion roof or cathedral ceiling, it's worth considering your insulation options.

Ceilings with exposed rafters

If your skillion roof has exposed rafters you can simply fit insulation between the rafters and line with plasterboard or similar on battens.

Use bulk insulation of the same thickness as the depth of the cavity, if space permits, with an R-value of R3.6 or higher. R-value is the measure of insulation effectiveness - the higher the better.

If the rafter depth is less than 190mm consider making more room for insulation by fixing additional spacer battens to the underside of the rafters as required.

EECA recommends that you consult a qualified builder and/or roofer before commencing any work.

Ceilings with hidden rafters

If your skillion roof has hidden rafters and you are planning on re-roofing or renovating this will be the time to fit insulation into the roof cavity.

When re-roofing, fit in insulation of a thickness that ensures a 25 mm gap between the insulation and the flexible roof underlay is maintained.

When renovating, remove the ceiling lining to fit in insulation from underneath. If the rafter depth is less than 190mm you may need to fix additional spacer battens to the underside of the rafters in order to be able to fit in insulation with a recommended R-value of R3.6 or higher. Again, make sure a 25mm gap between the insulation and flexible roof underlay is maintained. Afterwards, line with plasterboard or similar on battens.

EECA recommends that you consult a qualified builder and/or roofer before commencing any work.

Loose-fill insulation

While it may seem like a good idea to pump loose-fill insulation into skillion roofs, it can be difficult to assess whether the existing roof and roof underlay are in adequate condition for insulating. Maintaining the gap required between the insulation and the roof underlay is also very difficult.

Funding for insulation

If you have a skillion roof and your home was built before 2000, you are eligible for funding towards having your insulation installed. Note that the funding goes towards the cost of the materials and installation, not any other related building work.

>> Find out more about ENERGYWISE funding for insulation.