How to add roof insulation?

[richiemunnelly7]

hi, any advice appreciated, as you can see from the photo my roof has no insulation under the tiles and the up stairs of my house gets very hot and I'm guessing this is the reason, also it gets very noisy from the traffic on the road outside. Was thinking something like polystyrene sheets might help with both noise and heat or what would you guys recommend, budget is small as we've just purchased the property but I also don't want to waste my time on something that won't work.

Thanks.

[JacobZ]

Hi @richiemunnelly7,

Thank you for your question and welcome to the Bunnings Workshop community, it is great to have you with us.

I'll start by saying to take caution when in your ceiling cavity as there is a potential that asbestos containing materials are present. If homes were built or renovated before the 1990s, it's crucial to be wary of asbestos. Asbestos was commonly used in construction materials until the late 1980s and was not fully banned in Australia until December 2003. If you have any concern of this, you should contact a licenced asbestos testing company prior to conducting any work.  

There are options for polystyrene insulation such as this Bastion 1200 x 600 x 30mm XPS Multi Use Foam Board, but the price per square metre far exceeds traditional fibreglass insulation batts, so if your budget is small, I wouldn't suggest it's use.

Traditional fibreglass insulation batts such as these Earthwool R4.0 195 x 430 x 1160mm 7.5m² Insulation Ceiling Batts are a far more cost-effective option. They come in a variety of thicknesses and R values to suit your space. You might like to check out What Does R-Value Mean? for some guidance on selecting an insulation that works for you.

If you plan to install them yourself, I'd suggest you wear gloves, long sleeved shirt, long pants, enclosed shoes and a mask, as the fibreglass can be be extremely itchy and in a ceiling cavity you have a tendency to sweat causing it to stick to you.

Let me know if you have any further questions.

Jacob

[JacobZ]

Hi @richiemunnelly7,

To clarify, the insulation that has been installed previously may have compressed over time and be of a low R value so it would be worth having assessed by an insulation installer to determine whether it needs to be replaced and is the likely cause of the hot temperatures upstairs.

Some heat in the roof cavity is expected and it can be managed with the use of roof ventilation but if it is transferring through the ceiling into the upper level of the house, the current insulations viability should be assessed.

Noise-wise, it is far more likely that the sound is transferring through your walls and windows. You might like to check out this handy article on How to soundproof your home.

Let me know if you have further questions.

Jacob

[MitchellMc]

Hi @richiemunnelly7,

I see @JacobZ has provided some good information on potential reasons for the high temps and noise. I just wanted to let you know that insulation isn't normally installed under roof tiles, and you'd only typically see a thin metal sarking. If you do not see acceptable temperatures in the room beneath the attic with your current insulation, then it is likely inadequate and needs to be replaced.

Adding additional foam insulation could be an answer, or you might find it more cost-effective to increase the R-value of the current insulation by swapping it out.

Mitchell