new to forum & looking for some advise.
I'm in the process of fitting a new shower tray.
The old one has been ripped out & whilst removing the tiles
the plasterboard came away with them.
I've fitted new plasterboard & now want to fit the shower tray.
The tray is going into the corner up against 2 new pieces of plasterboard
so I want to know if I can just use silicone sealant in between the tray
and plasterboard or if the plasterboard needs some kind of sealer (e.g. PVA) applied first.
Don't know what KB has said because his post is waiting approval. In the meantime I'd recommend the following for a shower.
By all means initially silicone the gap between the tray and the board to fill the void if nothing else. Did it myself today and I'm going to suggest you cover it up in a moment anyway.
BTW Did you notice that the slides of the tray are probably sloping? That's to make it easy to remove from the mould (its called the release angle) but it's a PITA because with the bottom of the tray flush against the wall there will be most likely a large gap at the top. You want the gap to be smaller than the depth of tiles + adhesive otherwise you'll have a nice additional drain that's difficult to seal! The angle of the walls (assuming it's in a corner) won't be the same as the nice right angled corner of the shower tray either. You may need to cut the wallboards back at the bottom to allow the bottom edge of the tray to slide underneath to get the optimum fit.
Whether the tray has a tiling upstand or not you now need (don't think I can't afford to - I say can you afford not to) to tank at least the first metre above the tray. I recommend the BAL WP1 Tanking Kit, Dunlop (same company actually) do a cheaper branded one but I think that's being phased out. BAL is superior IMHO.
Prime with BAL APD or similar (please, please DON'T use PVA for reasons I've explained elsewhere on this site) and follow the instructions on the tin to apply the tape and waterproofing stuff! Wait 24 hours for it to dry and then tile over it directly. The tape and waterproofer should also cover the edge of the shower tray (and therefore also the silicone we talked about earlier)
By all means prime other areas with APD as well likely to get splashed (eg round the bath) before tiling but not PVA.
Other dry areas can be tiled on directly without priming - although direct on plasterboard gives the next guy who wants to retile a serious headache but that will most likely not be your problem.
An unsolicited plea though. Don't use combined adhesive and grout from the sheds. It's pants. BAL Whitestar or Greenstar for the adhesive and BAL Superflex for the Grout. No I'm NOT a BAL employee. I just believe in using systems designed for use with one another - I'll only use Dulux Undercoat with Dulux Gloss for the same reason. Then there's only one company to kick if it all goes wrong on you and Murphy says that one day it will.
Having built hundreds of houses for over 30 years we are amazed at the lengths people go to to protect a wall that, if tiled properly should never get wet. Plaese study tiling techniques and definately seal between board and tray but as to tanking the wall and all the other stuff, its madness.
Wall tiling, done properly, is a complete and total waterproof skin. If the grout is pushed into every joint well and thye tiles are not cracked, it will not leak. They are made to do this job, they are not just secondary decoration.
If water does get through the tiles because they have not been laid properly it will descend, gravity makes sure of that. It will find the tiniest gap no matter what you have put on the walls, and it will find its way to the lowest point (usually the ceiling of the room below) where it will eventually show itself. The longer it takes to get there ( And it ALWAYS gets there) the more damage it will do in hanging around and rotting joists etc. Tile properly and you will have no problems. If you spend time and a fortune waterproofing walls that have no business getting wet then you are less likely to take the care required to tile properly.
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