How to add insulation under rafters?

[samdyi]

Hello, I'm considering insulating under the tiled roof (rafters). Attached are some pictures of what I'm aiming to achieve.
1. The roof is insulated with Ceiling Batts, but the tiles are not completely sealed from cold air, dust, and pests from outside.  I'm hoping that Foilboard might be the solution. Please advise if there are other options or if anyone here has done something similar.

[EricL · Accepted solution]

Hello @samdyi 

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

Using Foilboard is a great way to insulate your tiled roof, the only other product that comes to mind is Ametalin 1500mm x 20m ThermalLiner Roof and Wall Shed Insulation. Both products provide insulation, but I believe that Foilboard is easier to install.

Here is a handy step-by-step guide: Foilboard Roof Insulation

Just a friendly note to our NZ members: The use of foil insulation products is prohibited.

If you have any other questions we can help with, please let us know.

Eric

[samdyi]

hello eric , this product has better R value , could i use this instead of others mentioned

https://www.bunnings.com.au/earthwool-space-blanket-r1-3-55mm-x-1200mm-x-15000mm-18m-insulation-meta...

[JacobZ]

Hi @samdyi,

I've been in touch with Knauf, the company who produce the space blanket, who've unfortunately told me that the space blanket is intended for use with metal roofs and is not suitable in a tiled roof application.

I've had a good look around and unfortunately the only product I can find that is suitable for this purpose is the aforementioned Foilboard or Ametalin ThermalLiner.

Let me know if you have any further questions.

Jacob

[nothandyman1960]

Does Bunnings know of a installer that could come out and do a quote for supply and install the foilboard ? Regards 

[JacobZ]

Hi @nothandyman1960,

Thank you for your question about insulation installers and welcome to the Bunnings Workshop community, it is fantastic to have you with us.

Unfortunately, we do not have recommendations for insulation installers. 

My suggestion is to use a service such as HiPages or True Local to find an insulation installer that operates near you.

Just a friendly note to our NZ members: The use of foil insulation products is prohibited.

Let me know if you have any further questions.

Jacob

[nothandyman1960]

Thanks Jacob

[happycoconut29]

I have similar sort of roof in my 1960s house  with terracotta tiles and i was wondering would sarking/foilboard fitted in the way shown in the pictures above lead to mould or mildew problems due to moisture not being able to escape and insufficient air flow to the attic?

[EricL]

Hello @happycoconut29 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thank you for sharing your questions regarding moisture entrapment in the roof cavity.

I agree with your concerns regarding moisture getting trapped in the roof cavity. I therefore suggest installing a Whirlybird/Natural roof vent to provide air circulation in your roof cavity. You can combine it with a Haron International 150mm Round Jet Diffuser Ceiling Vent to circulate air in your laundry and other parts of your house. They can be closed during wintertime and re-opened during summer.

If you have any other questions we can help with, please let us know.

Eric