Installing foil bac...
 

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Installing foil backed plasterboard

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Ideally want to avoid mechanical fix as the space is already small and not sure about putting holes through the foil.

Soudel do a spray on adhesive but not sure it'll stick to foil, it's not mentioned on the spec.

Any tips welcome, thanks


 
Posted : 05/07/2024 11:08 am
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Did my cellar years ago with foil back and just dabbed.

edit. But I guess you’re fixing to studding?  Sorry


 
Posted : 05/07/2024 1:14 pm
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You can get adhesive foil tape on a roll to go over the holes if you do decide to screw


 
Posted : 05/07/2024 1:58 pm
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Just remember that the foil is glued to the board, so if you glue the board to the studding then plaster over it, then that's a lot of weight on some glue.

Screw it on. A few small holes won't affect it much.


 
Posted : 05/07/2024 5:17 pm
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Ah sorry, it's going direct into a new extension on blockwork, it's in the kitchen so assumed foil backed was recommended here due to potential moisture.

The older half of the kitchen is 1920s brick with very limited damp course, I'm going to drill and rod that area, was thinking of going foil backed throughout, maybe overkill?


 
Posted : 05/07/2024 5:38 pm
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So not going on to any studding, was just thinking dab wouldn't hold on foil


 
Posted : 05/07/2024 5:39 pm
 Ewan
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Low expansion adhesive foam is what I used last time I installed some. Worked fine. Stick some mechanical fixings in too if you're worried.


 
Posted : 05/07/2024 7:25 pm
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Don't dab foil backed board, your relying on the foil adhesive.

Is this in an extension you say? You have cavity walls surely? Just stick standard board on with dry wall adhesive


 
Posted : 05/07/2024 10:55 pm
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Soudal spray adhesive is crap.
If your worried about loss of space, then mechanical would be fixed to 25mm battens, standard dot and dab would end up about 10-15mm thick once levelled, so hardly any difference in depth


 
Posted : 05/07/2024 10:57 pm
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Not quite the same thing but when I did my garage conversion I put celotex onto studs with mechanical fixings then used everbuild pink foam adhesive to stick plasterboard to the foil covered celotex. It was super easy to use and has not caused any issues in the 4 years since it went up. So I’m sure it would work in your application


 
Posted : 05/07/2024 11:34 pm
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Thanks, probs me over thinking it as per, It is a block cavity wall with no damp issues, I'll use std PB and dab on that, then use foil on the older side that has damp issues, that sides already set up for fixing onto battens.


 
Posted : 06/07/2024 7:58 am
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always thought the foil face of the board faced into the room, the foil is meant as a  vapour barrier not  waterproofing layer


 
Posted : 06/07/2024 8:05 am
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British Gypsum’s data sheet says foil backed (clue in the title) should be paper face out and mechanically fixed, not suitable for adhesive based fixing methods (board adhesive or foam).


 
Posted : 06/07/2024 9:33 am
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When I did a kitchen with damp walls, I used roofing latts to give a little air gap.

It also allowed me to put spacers behind the latts in order to get a perfectly flat and square wall.

Forgot to add, I also put visquine behind the latts on the bottom half.


 
Posted : 06/07/2024 9:39 am
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Forgot to add, I also put visquine behind the latts on the bottom half.

Just to be sure it couldn't breath ?


 
Posted : 06/07/2024 9:51 am
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I never said I knew what I was doing ?

But I had injected the walls with damp proof fluid and basically tanked the whole concrete flooded kitchen before lifting the outside door and raising the floor.

It was my one and only rental property and I got a bit carried away ?


 
Posted : 06/07/2024 11:57 am
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I used a Cerasit foam adhesive when I internally insulated with K118 boards, they are very heavy so fixings were required but this is because they need to hold the board in case of fire and them coming off the wall and blocking the escape route, only 3 fixings per board which is less than required for dot and dab.

would definitely use foam over dot dab adhesive as its quick and easy to use, there’s a roughneck gun that’s worth getting  if you close the gun and  wipe the end with white spirit the Teflon lined nozzle doesn’t need cleaning between use.


 
Posted : 06/07/2024 3:50 pm
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But you still used mechanical fixings which is what the OP doesn't want to do, but he has no choice if he wants the board to stay on the wall.


 
Posted : 06/07/2024 5:55 pm
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Thanks all, really helpful, I'll go down the half half route, dab the std PB and mech fix the foil sided area


 
Posted : 07/07/2024 8:23 am
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On the one side that's old brick there's no damp course so I'll inject/rod that - I had used roofing patterns and spacers to get flat, I put 25mm board insulation between the batterns, then 30mm over the top before fixing pb to the batterns. I was hoping the minimal air gap between the insulation and wall would help it breath but taking it all off after 18months it's still wet - injection damp course is the only option I think, the foils was to help make sure the moisture and damp smell stayed on the brick side and didn't permiate through.


 
Posted : 07/07/2024 8:32 am
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Foil backed plaster board unfortunately won’t help with damp and in most cases it will make it worse as any moisture in the area will condense on the foil side of the plasterboard. Foil backed plasterboard can only be mechanically fixed.
Foil backed plasterboard is not a Vapor control layer.
Try to treat your damp either by tanking the inner wall or find a way to allow a passage of air to travel behind your plaster board. If you have damp issues you are better off using moisture resistant plasterboard.
Avoid using drylining dabs as the plaster will draw moisture into the dabs, use a foam board adhesive such as Sodal board adhesive. Best way is to counter battern insulate the screw fix moisture resistant plasterboard over the top. Always use 12mm board.
Hope that helps.


 
Posted : 07/07/2024 8:20 pm