good practice for a shower cubicle install

[buttons129]

I have read many posts here and found the forum to be invaluable for an avid DIYer like myself who is an engineer by trade and looking for a professional opinion to see if I am taking the right options.

We moved into a brand new house 8 years ago but have recently found damp skirting boards in a bedroom on the other side of the shower wall. It seems that over time the flexing of the wallboards had loosened the grout etc. and… hey presto, a leaky shower (see photo). We decided to rip the lot out and replace the shower and floor tiles.

Anyway, here’s my method that I need advice on… im sure the pros will say it’s a bit overboard but where I lack in experience and water is concerned I would rather be safe than sorry. (I don’t have the pressure that a tradesman has, earning a crust from his materials and labour)



After the studwork was allowed to dry out…

Floor
1. 6mm Hardibacker secured to the existing 22mm floor grade chipboard with BAL Supercover Rapid flex (screwed down. 5mm staggered board joints)
2. Board joints taped and covered with BAL Supercover Rapid flex.
3. Fit tiles using BAL Supercover Rapid flex.

Shower area
1. Plastic membrane stapled to existing studwork
2. hardibacker500 screwed to studwork (5mm gaps between staggered board joints)
3. Board joints taped and covered with BAL Supercover Rapid flex.
4. Silicone seal wall, floor and ceiling joints before applying BAL WP1 tape.
5. Prime Hardibacker with BAL APD and apply BAL WP1 tanking coating.
7. install and seal shower tray
6. Fit tiles using BAL Supercover Rapid flex.

any help would be appreciated. a few posts say only tank if using plasterboard

thanks

 

[White Room]

Hi and welcome....5mm staggered board joints, they should staggered like a brick effect..

 

[buttons129]

Thanks and sorry for late reply, been on hols.
Boards are all fitted now and joints staggered where possible. About to get stuck in to rest of job this weekend and wondered if any other comments before I go past point of no return?

 

[bugs183]

Hiya.
I wouldn't silicon the joints on the hardibacker board as the WP1 tanking doesn't adhere to this, and in my mind creates weak spots and voids just where you really don't want them.
I prefer to get an expanding foam gun and a tube of 'instafix' from Screw fix. It's a proper adhesive and not some bodge foam!
This foam is really nice to use as it doesn't expand to much when applied, and the rate of flow from the gun will be adjustable.
Tape and protect the shower tray. Then fill all the joints with the foam. Give this an hour or so (tea an biscuit break), and then cut all this back flush with the boards. The whole enclosure will be solid and the WP1 will have a better surface to stick too.
I'll be honest i can't understand the plastic membrane part of the system as if water is getting to it then things are already too bad for the plastic to stop. Also is introduces an unbreathable barrier to water will condense on either side.
Once again i'd gun a line of instastik a;ong the stud work. Place the backer board on this and then screw. That really will give you a solid job.

 

[Spud]

Hiya.
I wouldn't silicon the joints on the hardibacker board as the WP1 tanking doesn't adhere to this, and in my mind creates weak spots and voids just where you really don't want them.
I prefer to get an expanding foam gun and a tube of 'instafix' from Screw fix. It's a proper adhesive and not some bodge foam!
This foam is really nice to use as it doesn't expand to much when applied, and the rate of flow from the gun will be adjustable.
Tape and protect the shower tray. Then fill all the joints with the foam. Give this an hour or so (tea an biscuit break), and then cut all this back flush with the boards. The whole enclosure will be solid and the WP1 will have a better surface to stick too.
I'll be honest i can't understand the plastic membrane part of the system as if water is getting to it then things are already too bad for the plastic to stop. Also is introduces an unbreathable barrier to water will condense on either side.
Once again i'd gun a line of instastik a;ong the stud work. Place the backer board on this and then screw. That really will give you a solid job.

putting in a vapour barrier is standard practice in the US Bugs and forms part of their regulations when tiling showers, the theory is to keep as much as the water vapour where it its created and to draw this off with a decent extraction fan this is supposed to prevent mildew spores contaminating others areas and protects wood stud from atomospheric changes there by making it more stable and less likely to move

 

[DHTiling]

if you want to use backer boards then IMO you will not go wrong with marmox boards.. totally waterproof and you can get all the joint glue and tapes and the boards from PHG wetrooms , link in my signature.

 

[bugs183]

I'd go with Marmox to, brilliant product, but it looks like he might have already bought them as he's starting today, so i'd presumed it would be to late.
I've seen this Gary on plenty of Youtube Vids, so i'm not going to argue with the U.S.government!!!!
It just seems odd, that if the vapour hits the plastic it will condense, and form water. Surely this will then be trapped inside the system and start causing problems elsewhere????
Up to you Buttons!!!!!

 

[buttons129]

I agree with the comments on the membrane, If the water gets that far then your already in trouble. Seemed good practice from many threads I have followed but may apply more to US installs as opposed to my UK project.

I have already fitted the membrane and the backerboard so the comments on the silicone waterproofing are good timing.

 

[Spud]

Marmox is top stuff a local supplier has started stocking it and have to say I am very impressed with what I have seen