Looking for advice on the best method of fastening plywood to concrete. I'm reluctant to drill into the concrete, so recommendations for suitable adhesives please. This is for the inside of a concrete sectional garage and will be non-loadbearing. TIA Iain
Depends a bit on the size of sheet of ply. For large sheets you will need something like a PU foam adhesive - you can get "board fix" adhesives in cans similar to normal expanding foam.
Smaller bits of wood with a close fitting gap, you may be able to fix with contact adhesive.
I would strongly (geddit?) recommend this stuff
alternatively look at various tests done by this chap
Car body filler
There are specialist adhesives at a price. Usually people don't want the be st, they want something that does the job & ideally they already have. PU, epoxy, car body filler, hilti gun, etc. Not PVA, it doesn't do gaps. Silico ne could work if you use a lot of it. If it's a damp floor most adhesives w ill fail.
NT
When fitting out my 20' x 10' concrete sectional garage / workshop I cut many 6" lengths of 4x2" sawn timber and glued each of them with the real Gripfill to the inside of each panel (so top, middle and bottom).
I then hung 8 x 4 sheets of 1/2" ply on top of each of the blocks and then added slotted racking uprights at each position and loaded the shelves ... and they have all been there 20+ years now. ;-)
After sticking the blocks on one panel and leaving them to cure overnight, I was able to stand on the bottom one and hang off the other two and noting moved (so I carried on with the rest). ;-)
After applying the Gripfill and pushing them into place, I just rested some lengths of wood up against them to stop them moving whilst they cured.
Cheers, T i m
Personally I'd glue battens to the concrete which is a lot easier and cheaper and would provide an air gap which would provide insulation in itself or could be filled. This would also make removal easier as well if this ever became necessary. Then screw the plywood onto the battens.
michael adams
....
So, eventually, will the plywood if it's not marine ply or otherwise waterproof.
Best building adhesive I've found for sticking wood to walls is gun-grade expanding foam (low expansion stuff)
I've used it for skirting boards, sticking un-supported insulation into the cavities under window openings etc. Couple of tips. give the 2 substances to be joined a quick misting with plant sprayer etc to speed up curing and give foam a few minutes to start expanding slightly before pressing boards into place. Bit like contact adhesive, I found it best to allow slight expansion and thickening of the foam as just pressing the 2 components together right away doesn't give enough foam substance to make an effective joint also keeping pressure on the boards once positioned reduces further outward expansion of the foam. I wouldn't try it with anything other than low expansion/volume foam though as it will almost certainly push the boards away from the wall.
e best, they want something that does the job & ideally they already have. PU, epoxy, car body filler, hilti gun, etc. Not PVA, it doesn't do gaps. Si licone could work if you use a lot of it. If it's a damp floor most adhesiv es will fail.
yes, but rather large difference in timescale. PU can turn to gloop in a mo nth on a wet floor.
NT
Not had much luck with that, concrete surface just comes away on the glue after a while I find. Brian
What PU are we talking about here? I only ask because I have some marine ply roofing over a wood store, and it has had 3 coats of PU varnish to waterproof it. I'm not convinced that the varnish is completely waterproofing the ply as sometimes a few small damp patches appear when it rains. Would it be the same or a different PU from the glue?
the best, they want something that does the job & ideally they already have . PU, epoxy, car body filler, hilti gun, etc. Not PVA, it doesn't do gaps. Silicone could work if you use a lot of it. If it's a damp floor most adhes ives will fail.
a month on a wet floor.
It was PU glue from screwfix or toolsatan. Might have been gorilla brand, n ot sure. I glued vinyl tiles to a slab - a month later the glue was just gl oop. PU is not fully waterproof, it's fine if it dries out but if it stays wet for a couple of weeks it's had it.
Your situation may be due to condensation.
NT
Gentlemen, I must apologise for lack of response to your suggestions. I did reply to most of you but, using Thunderbird, I hit reply instead of Reply All.
For clarity, the concrete in question is Sectional Garage with recesses in the panels. I wish to put some insulation in the cavities and plywood on top. Unfortunately space is tight and there is no room for a framework. Cheers, Iain
I did wonder if that was intentional, or not.
Can I suggest that you right click the small toolbar at the top/right of the message page, choose "customise" and then drag the "smart reply" button off the toolbar, and drag the "reply" button on in its place, the behaviour is more what people expect ...
Exactly like mine then.
Exactly as I did then.
Which is exactly why (20 years ago) I glued 6" lengths of 4x2" into each panel with Gripfill, put the insulation around and the ply over the top.
Because my panels were 2' wide and the play 8x4', placing the blocks in the middle of each panel gave me 2' increments and using H section ally sections between the panels, a very nice and sealed finish.
Cheers, T i m
I did something similar 4 years ago; I used plasterboard with foam backing (Knauf, which had about 15mm of foam in one side so there was some insulation plus a vapour barrier) . Stuck it directly on the raised parts of the concrete sections using 'no more nails' type of adhesive. Worked well.
snip
That's slightly reassuring - my main concern with gluing buildings together is the life of the glue.
I think my house will pretty much fall down if the expanding foam loses its stick :-)
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