Can I fix tile backer board with adhesive foam?

[JP_]

I've used everbuild foam for fixing insulation and plasterboard to brick, so happy with this product.

I now need to board a slightly uneven old brick wall for a bathroom. I can't decide whether to use hardiebacker again (which I found a bit of a nightmare in the previous shower room, but got the job done) or go for a waterproof, lightweight tilebacker board, like Wickes' STS Professional Tile Backer Board (can't seem to find Marmox, Jackoboard locally or with sensible delivery rates).

My concern is ensuring the board sticks to the wall evenly, without the foam forcing it out of shape - are these boards too flexible? I once used very thin 10mm insulation with foam and the foam expanded and made them unlevel.

If these boards (STS etc) are not suitable for foam, could I get away with just using the fixings? Or maybe lots of gun adhesive (recommendations?) and then fixing.

Talking of fixings - do you think these will be suitable? Stainless Steel Easy Fix Washers
Or is there a better option?

If this is not really suitable, then maybe I could just use the solid 6mm Hardiebacker boards again - but, if they are not totally level, could I have them skimmed to make level? Or is this a big no?

The wall is probably not as bad as I make it out to be ....

 

[^woody^]

Get panel adhesive foam that is made specifically for fixing boards, or low expansion foam. Either way you'll need some fixings too.

 

[JP_]

Yeah, found to use fixings. I think the everbuild foam is low expansion?.

What product would you use?

 

[Mr Chibs]

Why not buy one sheet and try with foam?

It also needs some screws.

I have used sts board For something different, I used puraflex from Toolstation to bond to wood and fibreglass. It’s very strong. But will cost a fortune to do a room.

I think you may be able to use Board adhesive, as from memory sts board is a cement based Covering. Again test a bit first to be sure.

 

[mrrusty]

you certainly can with solid boards like hardie. I've done it and it is no problem. As woody says use a foam adhesive not just foam - instastik or the pink equivalent. It's low expansion and contains adhesives. The foam allows you to position the boards accurately on a rough wall.

I suggest use just one or two additional fixings initially to aid positioning and stop the foam pushing the boards out of position. Once solid, follow up with additional fixings. I wouldn't personally rely on just foam if I was fixing heavy tiles, although I suspect it would be OK. I fixed using screws and plugs at ~300 centres.

I have never used the lightweight boards - just find the cement based backer boards solid, flat, easy to use. Never considered anything else. NOt sure what the advantages would be. Cement boards can be fixed just with regular screws and plugs.

 

[noseall]

you certainly can with solid boards like hardie. I've done it and it is no problem. As woody says use a foam adhesive not just foam - instastik or the pink equivalent. It's low expansion and contains adhesives

Lol, all foam has adhesive qualities, it sticks to everyone and everything! The specific adhesive/fixing foam (as opposed to gap filling foam) has a lower expansion rate.

 

[JP_]

I have Everbuild DryFix foam, I know that is super sticky as I have used it for all the insulation and plasterboard I've put up, and nothing has fallen down in the last 3 years, touch wood!

I plan to position the boards and drill the holes for fixings, then apply foam and press to wall, and while maintaining pressure with a prop, screw it in place. So it should be solid.

I used Hardiebacker in my shower and although it worked, it was hard to work with, and as not waterproof I had to tank the whole area. For this I hope to get the boards up much faster, and then just use tanking tape and solution on the joints and screw holes. The boards are really light, which is nice - I don't seem to be getting any stronger these days!

 

[JP_]

also, these boards are a perfect fit! The left hand wall is being insulation so that gap will be covered.

 

[mrrusty]

Lol, all foam has adhesive qualities

True, but if you compare the safety data sheets between just expanding foam and the adhesive type you will find they are different with higher concentrations of the adhesive compounds in the foams sold as adhesives.

 

[mrrusty]

Always used hardie or similar, but must say I do like the look of those sheets. I'll give them a go next time. https://s7g10.scene7.com/is/content...oard-1200-x-600-x-10mm~GPID_1100488308_TECH_0

 

[dermu]

Hi, I've recently started googling for the very same reason and come across this thread. I've started doing my shower room and wanted to go over existing tiles which are all in tact on a solid wall, but they are thin tiles 5mm so I didn't want to make a mess and remove them. They are tiled onto a plastered wall. I had decided to overlay them with a tile backer board 10mm. Why make a mess and more work to save 5mm of space, was my thinking. I used thermopanel which I got cheap online at around 8 quid a board 1250x600 and also some left over sts 10mm tile backer board from a previous job. I stuck the boards on with CT1 power grab and bond, trust me this stuff is brutally strong and creates a instant grab. I went on with 12 mechanical fixing per baord all stainless steel washers and screws. It's now

rock solid and not going anywhere. In fact to remove the boards it would mean knocking down the wall
I tanked all joints and have peace of mind it's job well done. The boards are really good as they take out imperfections by a few mills off the wall for a nice flat and clean surface.
Now all left to do of get a tiler in, which is beyond my skill set