Fixing NoMorePly on brick wall

[powernun]

I have taken my bathroom back to brick and have purchased the NoMorePly 12mm fibre cement boards to install. On some walls, the bricks are laid with the stretcher face showing, allowing a maximum fixing depth of 115 mm, while on another internal wall, the frog face is showing, allowing a maximum fixing depth of 80 mm. I am going to use adhesive foam and mechanical fixings, allowing 10-20mm of adhesive foam bed between the board and the brick.

The plan is:

1. Prep the wall surface, use SBR on both wall and cement boards
2. Damp with water both surfaces
3. Apply SOUDAL Plasterboard adhesive foam on cement board and let it get stringy
4. Press the board to the wall, level, let it set for ~20min
5. Drill 6mm holes through cement board to the brick at the depth of 40mm for each corner of cement board
6. Push in Fischer DuoPower 6 x 30mm plugs into the brick
7. Use SPAX Stainless Steel 5 x 80mm screws to secure the boards
8. Repeat the process above and use NoMorePly adhesive between the joints

Have a few questions about the above plan:

- Are the screws and plugs enough to hold the cement boards and the weight of the tile adhesive and tiles? Each plug should hold 50kg of force on solid brick (so 200kg total per board). This in combination with the plasterboard expanding foam adhesive feels like should be plenty strong.
- Are stainless steel screws necessary, or would regular SPAX Wirox screws work? I am going to tank most of the walls for tiling, however some will be painted and need to be plastered. The stainless steel variety are hard to find in 5 x 80mm.
- Some bricks are sticking out way further than others (2-5cm). Can I grind them with a masonry grinder disc? It is only few brick per wall, rest are fairly even. I don't think the structural integrity would be a concern.
- Should the boards be staggered?

 

[endecotp]

Is there insulation in the wall?

Installation instructions here:

https://nomoreply.co.uk/wp-content/uploads/2025/10/12mm-NoMorePly-Installation-C-Fold-Flyer.pdf

 

[cdbe]

You're massively overthinking and over engineering this.

 

[mrrusty]

10-20mm of adhesive foam bed

If you need 10-20mm use a dab adhesive and pop a few screws and plugs through once it's solid if you want. Unless you fit some sort of timber packer to get the levels, you'll never use foam at that thickness. It's best used pushed tight to the wall.

 

[powernun]

Is there insulation in the wall?

Installation instructions here:

https://nomoreply.co.uk/wp-content/uploads/2025/10/12mm-NoMorePly-Installation-C-Fold-Flyer.pdf

Apologies I should have mentioned that I have gone through the NoMorePly instructions already and have also contacted them and they OK'd using expanding foam with 8 mechanical fixings.

You're massively overthinking and over engineering this.

Story of my life , any way I could simplify things?

If you need 10-20mm use a dab adhesive and pop a few screws and plugs through once it's solid if you want. Unless you fit some sort of timber packer to get the levels, you'll never use foam at that thickness. It's best used pushed tight to the wall.

I was worried about that too, that the wall might be too uneven for foam. But I chatted with a builder mate who told me he has used foam for up to 30mm beds with ease and even up to 50mm beds but by layering the foam (add a layer, let it dry completely, add another layer, let it get stringy and push to the wall). He said the panel was rock solid and not going anywhere (even without mechanical fixings).

I will definitely test the more uneven part of the wall first to see how it goes before fully committing to the foam.

 

[mrrusty]

I was worried about that too, that the wall might be too uneven for foam. But I chatted with a builder mate who told me he has used foam for up to 30mm beds with ease and even up to 50mm beds but by layering the foam (add a layer, let it dry completely, add another layer, let it get stringy and push to the wall). He said the panel was rock solid and not going anywhere (even without mechanical fixings).

I will definitely test the more uneven part of the wall first to see how it goes before fully committing to the foam.

Yes, you could, but foam when initially applied has no body, so when you push the panel in place the foam will compress to almost nothing. If you want it 10-20mm off the surface, as your builder says you either have to build up even layers of foam, or use some wood blocks to stand the panel off while the foam expands and dries. That's a right faff.

As I suggested, use board dab adhesive, place the board and knock in to position with a heavy block of wood. With dab adhesive the board will stay in position while it dries, whereas with foam, if there is a thick bead it will be expanding and pushing that board outwards. Foam has it's place, but not really for a 10-20mm stand-off.

The other problem with foam is that if you let the surface skin off before you position, it won't stick properly. When fixing boards with foam its easier to foam the board not the wall, because trying to squirt it on a vertical wall without some of it rolling off under gravity is a lot harder than laying a board flat and applying even beads

And welcome to the black hand gang (you'll see )