What insulation to use under new corrugated patio roof?

Hi, removed damaged laserlite roof on patio and replacing with corrugated instead. Looking at insulating between the battens and new corro. I was looking at this insulation - Ametalin Thermal Liner Roof and Wall Shed Insulation.-but there will not be an air barrier between the insulation and the corro except the gaps in the corro profile. Will this do the job without causing moisture issues please? Thanks for your help.

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Comments

JacobZ

Hi @Karoshep,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Have you got any photos of your patio roof that you can share? The description helps but seeing it is really invaluable in determining the best product and methods for your specific situation.

I note in the ThermalLiner Installation Guide that -

"Installation can be above the battens, but performance may be reduced, and problems may arise under certain environmental conditions. Specifically, condensation forming under the roof may pool behind battens. Condensation may also form on the underside of this product where contact is made with the roofing material."

If you are unable to create an air gap, then condensation can occur where the liner is in direct contact with the roofing material.

If the circumstances of your installation do not allow for an airgap, you may need to look at alternatives such as those shown in some of these similar discussions that you might like to check out:

How to insulate Colorbond patio? by @tanmaried

How to stop condensation on a patio roof? by @condruss

How to add insulation to a sunroom with Colorbond roof by @GaryWeiley

How to insulate a patio roof? by @dingo22

Once you can upload some images, we can look at the situation and see if there is an alternative option that could be better in your situation.

Let me know if you need a hand uploading images.

Jacob

A note for our New Zealand readers - The use of foil-faced insulation products is banned in New Zealand.

Karoshep

https://www.workshop.bunnings.com.au/discussion/comment/61472#Comment_61472

with the laserlite-this has been removedawaiting the new colourbondnew batons

Karoshep

https://www.workshop.bunnings.com.au/discussion/comment/93213#Comment_93213

Hi Jacob, thanks for the advice. I have attached pictures with and now without the laserlite. The new roof is colourbond. I did see that advice on the thermal blanket hence my questions. Thanks.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/112831#Comment_112831

Hi @Karoshep,

As the roofing is off and you have access to the top side of the battens, I suspect a product like Earthwool Space Blanket, would be the best way to go.

Earthwool Space Blanket is made from fibreglass bulk insulation with a foil facing attached. The fibreglass traps air and slows heat movement, which helps stop the roof sheeting from getting much colder than the air underneath it, reducing the conditions that cause condensation.

The foil layer acts as a vapour barrier and reflects radiant heat. This limits moist air reaching the underside of the roof and helps keep temperatures more stable, which together reduces condensation forming on the roof sheets.

You'll just have to let me get in touch with Knauf when they reopen tomorrow to ensure that it can be used in this semi-exterior situation.

Please bear with me and I will get back to you when I have been able to speak with the team at Knauf.

Jacob

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/123959#Comment_123959

Hi @Karoshep,

I've spoken with the team at Knauf, who have confirmed that it could be used in your situation, as long as the outside edge of your insulation is protected from any water rounding the edge of the corrugated sheeting.

Typically, when it is installed inside a home, it would be protected by the fascia and gutter.

In your situation, you may have to install an additional batten on the end of the rafters to lock the outer edge in place and then tape the insulation to the underside of the corrugations with insulation tape.

Let me know if you have any further questions.

Jacob

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