June 3Jun 3 Good evening my friends. As the football is over and my working year comes to a close (university) it means I can get down to business so I'm ordering my supplies. My shower will be pressed against the only external wall in the room, it's currently back to brick so I was going to backer board that wall, the type with the foam core. I'll just MR board the rest of the room. The room is very small, any centimetre gained is a bonus. What are my options at the shower area, tile adhesive, foam directly to the wall followed by screws and washers? Cut my space loses, batten the wall out with 20mm deep battens and go against that? If so, insulation between said battens? Sack off all of the above, MR pasteboard and tank? Opinions welcome. Edited June 3Jun 3 by Super_Paulie
June 3Jun 3 Never seen a need to tank a shower room and in my 60 plus years and never seen an issue. Only ever used moisture resistant plasterboard around the shower and normal elsewhere. Tiles direct to the plasterboard. If you foam the plasterboard on or batten and screw it's not going anywhere quickly.
June 4Jun 4 Where’s the pipework, that might dictate what you do, are you going to chop into that wall or build a stud wall in front of it.
June 4Jun 4 My 10 pence worth is if the wall has not got EWI I would use XBS bonded and screwed back to the whole wall. It's not going to add a lot of insulation but it will reduce condensate and in turn mould. You can tile and plaster XBS boards
June 4Jun 4 I really like the XPS backer boards. Lots of thicknesses, lightweight, easy to cut and fix, waterproof. Fix with adhesive foam or screws and washers.
June 4Jun 4 Author There is no EWI, it's a cavity wall though. So direct connection to the wall with say 12mm XPS backer board is my best option here?
June 5Jun 5 On 03/06/2026 at 22:37, JohnMo said: Never seen a need to tank a shower room and in my 60 plus years and never seen an issue. Only ever used moisture resistant plasterboard around the shower and normal elsewhere. Tiles direct to the plasterboard. If you foam the plasterboard on or batten and screw it's not going anywhere quickly. This is pretty crap advice? I've done a LOT of insurance work over the 30+ years of me doing 'this kinda thing' and tanking would have saved so many homes from very significant, long term erosive water damage; all caused by leaking tiles / grout / sealant / shifted baths and shower trays etc etc. Tank the FECK out of it and you'll never look back.
June 5Jun 5 On 04/06/2026 at 19:18, Super_Paulie said: There is no EWI, it's a cavity wall though. So direct connection to the wall with say 12mm XPS backer board is my best option here? This is best, if you don't want to lose GIA with insulated stud walls. Dab the boards on and apply the dab to the boards. Poke a hole through the centre of each dab before applying to the wall, as markers, and when the dab is dry you drill back through and mechanically fix with corrosion-resistant fixings and washers. Foam at the footer, header, and sides. Leave a 3-5mm gap between the boards to inject foam in the gaps as dab must NOT be allowed to come through these gaps. That would bridge both cold and moisture, in the worst case.
June 6Jun 6 10 hours ago, Nickfromwales said: This is pretty crap advice? I've done a LOT of insurance work over the 30+ years of me doing 'this kinda thing' and tanking would have saved so many homes from very significant, long term erosive water damage; all caused by leaking tiles / grout / sealant / shifted baths and shower trays etc etc. Tank the FECK out of it and you'll never look back. Whatever, I'll keep doing what I do, as I said never had an issue.
June 6Jun 6 1 minute ago, JohnMo said: Whatever, I'll keep doing what I do, as I said never had an issue. Indeed. Don’t ever change! If we couldn't bicker over these things the forum would be a whole lot duller .
June 8Jun 8 Author On 05/06/2026 at 22:31, Nickfromwales said: This is best, if you don't want to lose GIA with insulated stud walls. Dab the boards on and apply the dab to the boards. Poke a hole through the centre of each dab before applying to the wall, as markers, and when the dab is dry you drill back through and mechanically fix with corrosion-resistant fixings and washers. Foam at the footer, header, and sides. Leave a 3-5mm gap between the boards to inject foam in the gaps as dab must NOT be allowed to come through these gaps. That would bridge both cold and moisture, in the worst case. Seems quite faffy, especially with the small size of the individual backer boards... Should I just batten it out with 2x1 and be done with it? No pipes or anything else on that wall, it's back to brick and just needs to be tile-able and not eat into the already tiny room.
June 8Jun 8 1 hour ago, Super_Paulie said: Seems quite faffy, especially with the small size of the individual backer boards... Should I just batten it out with 2x1 and be done with it? No pipes or anything else on that wall, it's back to brick and just needs to be tile-able and not eat into the already tiny room. Quite ‘faffy’? It’s a brush….. Or go buy battens, and plasterboard, and cut them, and make mess, and shape that lot to fit the space. Faffy?????? 🤷♂️🤷♂️🤷♂️🤦♂️🤦♂️🤦♂️🤦♂️
June 8Jun 8 Author 16 minutes ago, Nickfromwales said: Quite ‘faffy’? It’s a brush….. Or go buy battens, and plasterboard, and cut them, and make mess, and shape that lot to fit the space. Faffy?????? 🤷♂️🤷♂️🤷♂️🤦♂️🤦♂️🤦♂️🤦♂️ apologies 🤣 So i have this straight, XPS board, dabs on the board as opposed to the wall, dab about the back but away from the edges. Push that plumb, when its gone off drill through the dabs in various places. Sound about right?
June 8Jun 8 42 minutes ago, Super_Paulie said: apologies 🤣 So i have this straight, XPS board, dabs on the board as opposed to the wall, dab about the back but away from the edges. Push that plumb, when its gone off drill through the dabs in various places. Sound about right? Ya 👍
June 18Jun 18 Author Tile adhesive or traditional plasterboard adhesive? The wall is brick with cavity. On 05/06/2026 at 22:31, Nickfromwales said: Dab the boards on and apply the dab to the boards. Poke a hole through the centre of each dab before applying to the wall, as markers, and when the dab is dry you drill back through and mechanically fix with corrosion-resistant fixings and washers. Foam at the footer, header, and sides. Leave a 3-5mm gap between the boards to inject foam in the gaps as dab must NOT be allowed to come through these gaps. That would bridge both cold and moisture, in the worst case.
July 20Jul 20 Author On 05/06/2026 at 22:31, Nickfromwales said: Dab the boards on and apply the dab to the boards. Poke a hole through the centre of each dab before applying to the wall, as markers, and when the dab is dry you drill back through and mechanically fix with corrosion-resistant fixings and washers. How many you reckon is needed on a 1200x600 WEDI panel into the brick? Searched the entire internet and can't find the answer...
July 20Jul 20 5, if the same as jackoboards, their instructions suggest one in each of the corners and 1 to the middle. Edited July 20Jul 20 by crispy_wafer
July 20Jul 20 Author 13 minutes ago, crispy_wafer said: 5, if the same as jackoboards, their instructions suggest one in each of the corners and 1 to the middle. Great find, cheers Crispy. I was planning on dabbing rather than full fix but I guess it won't be far off once it's compressed anyways.
July 21Jul 21 Author On 05/06/2026 at 22:31, Nickfromwales said: Leave a 3-5mm gap between the boards to inject foam in the gaps as dab must NOT be allowed to come through these gaps. Ok, boards are on. Just need to do the mechanical fix and foam the gaps as above. Two questions have arisen though. 1. Does it matter if the screws are stainless, they'll be getting tanked over anyways? 2. I've got FM330 in the gun, but I'm thinking I should be maybe using something more sticky between the gaps like Insta Stick?
July 21Jul 21 Author On 18/06/2026 at 18:32, Nickfromwales said: Traditional dab is fine And adding number 3 to this! When I went to remove the spacers between the boards they just came straight off... The boards just didn't take to the knauff plasterboard adhesive. I guess I'll go tile adhesive and try again.
July 21Jul 21 SBR or acrylic primer on the dry boards is best practice. Leave to dry before installing. Yes, I could have said sooner, I just have way too many plates spinning atm, sorry!
July 21Jul 21 Author Just about to get some tile adhesive instead, sure it'll be stickier! I'll SBR the boards as well when I'm back in. No biggy, learning curve innit, appreciate all the help.
July 21Jul 21 Author Much better this time. Used some rapid set and did 2 boards at a time, seems solid now fingers crossed.
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