Firestone EPDM onto foil backed boards

[Keiron]

Good morning all,

I've been asked to help a friend out with a roof and before I agree I'm trying to find an answer to this teaser

He has a warm roof construction, with joists below, then firrings, OSB3, 150mm foil backed Celotex. Now, he wants to adhere the EPDM directly to the foil backed boards with the contact adhesive, and all the information I can find says that it should be laid onto boards, ply - osb, etc.

Now, the contact adhesive does say it will adhere to pretty much anything, wood, metal, brick so I can see his point - but I'm just not able to get a proper answer out of anyone. I have asked Avenir and Permaroof and they both say bond onto board.

Has anyone a similar experience, or can offer a definitive answer please? I've done all the research I can think of.

Kind regards

 

[ree]

Call Celotex.

 

[Keiron]

I've got a technical query into Firestone, just thought I would ask the collected expertise of people who have real world experience!

 

[cotswoldbuilders]

Use the insulated boards with ply already glued to them, or fit t&g osb3 over the insulation.

 

[catlad]

Well on a practical point if you bond directly to the insulation then it will be very soft and prone to be damaged easily, probably before you have even finished the roof.

 

[Mw Roofline]

Even if you did bond onto foil there would be no warranty and it would look like a patchwork quilt. You will need to screw new ply onto the insulation and bond the rubber to the new ply. 18mm seems overkill but you will need this because you'll need to countersink the long screws deep into the ply. Not much room for countersink on a thin ply.