Ceiling insulation

It is now recommended to have ceiling insulation with a total R value 4 or greater for Tasmanian conditions.

If you already have bulky insulation you can estimate the R value by measuring the thickness of the layer. A rough guide is that every 1 cm of insulation is equivalent to R ~0.2 (eg. insulation thickness 10 cm equivalent to R value ~2, insulation thickness 20 cm equivalent to R value~4).

Alternatively there are often half empty bags or wrappings left in the roof cavity which will have the R value printed on the bag.

Sisalation, sarking, roof blankets and building materials all add additional insulation to a building. Apart from insulation blankets, they only add neglibibly to the total Rvalue.

If insulation is inadequate then it can be supplemented by adding another layer of batts or a blanket to boost the total Rvalue to R4 or greater. Ceiling insulation can be made from cellulose, glasswool (fibreglass), rockwool (mineral wool), polyester or wool.