How should a roof in Sydney be insulated?

The most effective way to control the living space temperature is to place to place good insulation right on top of your ceiling. So, if you do not have ceiling insulation, this is the first step.

Then insulation directly under the roof is next. The pictures below best show how this is achieved:

How a roof should be insulated
Example of a typical insulation solution under a new colorbond metal roof

Step number 1 will to turn your home into a fridge. A fridge keeps its contents cool in the middle of a hot summers day. by having an insulated ‘skin’.
Step 2 just makes the temperature in the attic more bearable so that the ceiling insulation does not need to work as hard.
Combine the two and you will have the best combination.

If you have cathedral ceilings, then there is limited space to install ceiling insulation. In this case, the solution is to ‘super – insulate’ between the ceiling and the outer roof. Aircell insulation is an option here because it is thinner and has a higher R rating, but it comes at a price premium of about $3 per square metre. This type of insulation under the roof and a stuffing of ceiling batts at any available cavity is especially effective in cathedral ceilings and where there is no cavity to create an effective insulation layer.

0 0 votes
Article Rating
Notify of
Newest Most Voted
Inline Feedbacks
View all comments
9 years ago

I have a townhouse with a flat roof on the upper story. The ceiling space is negligible so cannot use batts etc. Is there en external insulation solution, eg gravel or similar?

9 years ago
Reply to  Peter

Gravel does not insulate. It is usually used on top or membrane roofs to protect the membrane from sun, bird and pedestrian damage. Gravel is also put on top of polystyrene insulation which can be laid on top of the membrane roof to insulate it. If you have a membrane roof, you can use this method.
If you have a metal roof, the polystyrene and gravel trick will not work too well.
The best option I can think of is to pull the roof sheeting off and install something like “Aircell glareshield” insulation- then put the roof sheeting back.