Sealing shower tray

[kev16097]

I'm refitting the ensuite shower. Always had leaks with it and figured best option was to rip it out and start again. One issue I have is that the tray is 750mm square (walls on three sides), but the enclosure was 800mm across before fitting the new boards. I've used aquapanel (12.5mm) on the walls, so that take the space down to 775mm, so still a 25 mm gap. My plan is as follows, but want to be sure I'm not doing something dumb before proceeding! The tray is a solid one (not plastic), which has no flex in it, the floor is solid (I've fitted a piece of 18mm marine ply for the tray area to sit on) and the tray itself is mounted on a fixed metal tray support

1. Fill the gaps around the edges of tray with spare aquapanel to prevent lateral movement of the tray. Take this up to just below the edge of the tray
2. Seal over the filler panels to the level of the tray
3. Use a PVC L shaped profile, mitred at the two corners, sealed to the aquapanel and the lip of the shower tray
4. Tile to this edge with a bead of sealant between the bottom of the tiles and the strip

The profile I'm looking at is 1mm thick. There will be 20mm height behind the tiles and about 10 mm overlap around the tray (which will have sealant between it and the tray). The tiles are 300mm by 600mm so I don't think the bit with the profile behind it will have much impact on adhesion.

I'm thinking this should be pretty leak proof, and since a lot of the sealant is covered by the profile, and also protected from mould and what have you. I believe there will be little or no movement of the tray to put pressure on the sealant.

So am I missing anything? Is this a stupid idea?

Thanks,
Kev

 

[footprints]

i would tile directly down onto the shower base myself, the exposed mitred plastic will always be a weak point.
A mastic bead along the joint should finish it OK.

 

[kev16097]

i would tile directly down onto the shower base myself, the exposed mitred plastic will always be a weak point.
A mastic bead along the joint should finish it OK.

Thanks footprints. The problem with that is the gap between the boards and the tray, about 12.5mm on each side. I did consider adding shims behind the boards, but decided against it in the end, due to the thickness involved. How would you see the plastic being weak? I've seen similar products designed specifically for tiling, though they tend to have a lip for the tile to sit in

 

[footprints]

You need to pack out the walls so that the tiles overlap the tray.

 

[chappers]

yep just reboard the walls with 12.5mm backerboards

 

[kev16097]

Thanks both. Given I've already put the new boards up, is my original plan sufficiently worse than what you've suggested to make it worth taking them down and doing that? I respect your experience, but I'm not sure how much of a difference it will make, if you see what I mean?

 

[footprints]

The main cause of shower tray leakage is incorrect installation eg: tiles taken down the side and the tray fitted afterwards you are totally reliant on the silicone which will fail.
If the tiles overhang the tray even without silicone water will tend to run off the ledge into the tray as opposed to under and down the side. The mastic then just helps to direct the water instead of forming a gully for it to collect.

 

[footprints]

Just double up on your boarding.

 

[kev16097]

Thanks. Would I be okay using standard plasterboard as the back layer, and would I need longer screws to support the aquapanel?

 

[footprints]

I would not use plasterboard or chipboard/MDF as with the slightest amount of moisture it turns to mush.
Aquapanel or Marmox board is the way to go.
And yes some longer screws.

 

[chappers]

to be honest there are many ways to skin this cat, you might as well batten out the wall if you are going to take off what you have already put up.

 

[footprints]

to be honest there are many ways to skin this cat, you might as well batten out the wall if you are going to take off what you have already put up.

You have to be careful about what you say these days regarding the treatment of cats mate!
http://www.dailymail.co.uk/news/article-4788666/Cat-s-eyes-renamed-complaints-tourists.html