Recessed Shelves in Showers : Waterproofing The Joins?

[rideforever]

I have an internal shelf in the shower, all tiled over with mozaic, seems to leak a lot, also because it's flat rather than sloped.
I'd like to strip off the tiles and waterproof the joins in the plasterboard the tile over with a slight slope.
What's a good product or solution for waterproofing the joins in the plasterboards?
Cheers

 

[sircerebus666]

It's pointless waterproofing plasterboard joints as plasterboard itself is not waterproof

Properly grouted mosaic tiles should not leak , have you got a pic of this shelf?

A slight fall is not a bad idea though

 

[JaimieH]

Instead of using plasterboard, construction board should be used and all joints/corners (internal and external) taped with waterproof joining tape, or at the very least a thick continuous bead of silicone. A fall should be set on the shelf before tiling. Tiles should have 100% coverage beneath them and all internal joints/corners should be silicone, not grout.

 

[Toria J]

You can get premade recessed shelves that you set in the wall - that could be an option.

 

[rideforever]

Cheers yeah premade is ideal if a new shower, but I just want to modify the existing by stripping off the shelf tiles adding a slight fall and hopefully I have a few mills to put some thin joint tape over the seams or fibreglassing on the edges, without pulling off all the tiles from the other walls. And then just replace the shelf tiles.

 

[rideforever]

How to I make the drop ?
If I get some wood trim and drill it at the back, do I need to fill in the triangle with plaster or something and then tile over the top ? Or is there a better filler or way to fill in the triangle?

 

[sircerebus666]

Just use the tile adhesive to give you the fall it's only slight after all

 

[rideforever]

Cheers

 

[rideforever]

I ended up having to raise the shelf height by 1/2" so got some timber cut at the yard and I used Gorilla waterproofing tape on the old shelf and also on the joints on the new timber ... I also had some some 3mm birch ply so used that to make a solid incline so the water flows off nicely. Looks good all told.
The old shelf had definitely been leaking based on the darkened patches ... all due to the lack of an incline on the shelf.