How to insulate a skillion roof?

Welcome to the Bunnings Workshop community @needadvice. It's sensational to have you join us, and many thanks for your question about insulating a roof.

Any air gap is better than none at all. Typically, insulation batts offer the best thermal insulation out of the available options, and you'd only not use them if you didn't have the space to fit them. In your 90mm of height, you can easily fit 90mm thick insulation batts, which will generally give you an R2.5 rating.

Please let me know if you have any questions.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/49795#Comment_49795

Thank you I will.
Will thermal liner make any difference to stopping the radiant heat more than normal staking? Thanks

https://www.workshop.bunnings.com.au/discussion/comment/86975#Comment_86975

Yes, a thermal liner will typically provide a better break than sarking, @needadvice. Sarking is predominantly used to capture water that has leaked through your roof and divert it to your eaves and out of the roof space. It has very little insulation value.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/108929#Comment_108929

Thank you. There is an open veranda, needing a new roof . Would there be any point in using the thermal liner there also? As it’s open on 3 sides. Plus how durable is it if it’s not covered by a ceiling?

also how many rolls of Ametalin 50 m tape for a 80 sq meter house? Thanks

https://www.workshop.bunnings.com.au/discussion/comment/121787#Comment_121787

A thermal liner doesn't provide much insulation by itself. Insulation batts provide R2.5, whereas thermal liner provides R0.1. Enclosing the ceiling with Hardieflex would likely provide better insulation.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/129890#Comment_129890

Thanks . About the Ametalin 50m tape? I’d one roll enough?

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/135005#Comment_135005

As the tape will need to be used on each location where the liner overlaps, it will depend on the size and orientation of the thermal liner and the dimensions and style of the roof.

If you could provide a quick sketch with the width, length and style of the roof, I'm happy to check for you, but I would be surprised if one 50m roll would be enough. It is likely you would need more.

Let me know what you think.

Jacob

https://www.workshop.bunnings.com.au/discussion/comment/138383#Comment_138383

43 sq meters floor under skillion roof. 36 sq meters floor under normal roof.
I think I’ll need 3 rolls of the thermal liner. Would this be correct? Plus tape rolls?

thanks

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/140629#Comment_140629

Hi @needadvice,

I'd pick up four just to be on the safe side, you can always return full rolls that you don't use.

Let me know what you think.

Jacob

https://www.workshop.bunnings.com.au/discussion/comment/142277#Comment_142277

Thanks. Did you work out how many roles of tape?

also the sq mtrs of batts is that based on sq mtrs of floor area on a normal pitch roof?

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/143452#Comment_143452

We'd need to know the actual dimensions of the roof, not just the square meterage, in order to calculate how much tape you'd need.

You need a piece of tape for every overlap, so if there are for example, 5 overlaps that are 8 metres long, you'd need 40m.

We'd also need to know which specific rolls of thermal liner you were using as they come in different sizes which will affect how many overlaps there are.

The amount of insulation batts is relative to the square meterage of the ceiling space it is covering. The square meterage of the ground is going to be pretty close to this.

Jacob

https://www.workshop.bunnings.com.au/discussion/comment/143452#Comment_143452

Hi I’ll work out the tape today. Yes it is based on sq m of floor space.

https://www.workshop.bunnings.com.au/discussion/comment/144348#Comment_144348

Once you provide the dimensions of the space, we'll be able to assist you with product requirements more accurately.

Let us know if you need further assistance with your project.

Mitchell

https://www.workshop.bunnings.com.au/discussion/comment/144348#Comment_144348

hi how many boxes of these for 3 rolls of Ametalin thermal liner? Thanks

https://www.workshop.bunnings.com.au/discussion/comment/144348#Comment_144348

Thanks I got another roll of tape.

https://www.workshop.bunnings.com.au/discussion/comment/144994#Comment_144994

The Ametalin should be fixed no greater than ever 150mm along your ceiling joists. The number of required fixings would be dependent on the spacing of your ceiling joists and so it's difficult to give you an exact number. 250 in that box should get you most of the way there, but it would be handy to pickup a second box just so you have them on hand if you run short. You can always return the second box for a refund if you don't use them.

Here's the Ametalin thermal liner installation guide.

Mitchell