Silicon Sealing A Shower Tray

[WSB]

I know when sealing a bath, you must fill with water before applying the sealant but does the same apply for a shower tray?

Of course, can't fill the tray full of water but was thinking of putting some weights on it before the sealing.

Mind you, my situation is slightly different as fitting multi boards which will sit within upstands on the tray and i guess to a certain extent, I move with the tray? Or maybe not as they'll be stuck to the surrounding walls.

On another note, how much of a gap should I leave between the top of the multi board and ceiling?

Thanks all

 

[Mr diy a lot.]

If you shower gray is acrylic stone resin then it’s pretty heavy so the whole weighting it down thing is not really necessary. If it’s a light weight tray - then you might want to stick it down with a scribble of no more nails for belt and braces and put a couple breeze blocks on the top until she is all set. Although I’m not a believer in those light weight shower trays - I think they can sometimes feel flimsy and cheap and like they won’t last as long and or could be prone to movement. I have always taken the view with installed shower trays that it’s there for life so should be robustly installed and you want zero movement. Nothing should be moving or expanding - it’s not a road bridge you are building. Movement in bathroom installs is the enemy of longevity.

Then silicone it fully in around all the edges - really pushing the silicone down into any gaps between the tray and the wall(plasterboard or brick work) is all helps to act like a glue to hold everything firmly in place. Then once all that has set in hard you can glue or screw in your multi board sub layer ready for you final layer(tiles etc?). It’s also fine to put the multiboard on the wall all the way to floor level before the shower tray and install the shower try hard up against the multiboard but depends how you have measured it up - might be too late for that option.

Multiboard should go all the way the the ceiling as it’s purpose is to create a smooth and solid sub layer to stick all the tiles too.

 

[Madrab]

Depends on whether the tray is liable to movement or not and that depends on what it's sitting on and the type of tray.

As far as Multiboards are concerned then normally they would form part of the wall substrate, like plasterboard or backer board. The would be fitted to the wall - floor to ceiling - then the tray would be fitted up to that wall and sealed. Then final wall surface would then run down to the tray edge, over any upstand and then sealed again.

 

[WSB]

Many thanks. Some great advice there