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Waterproofing a shower over a bath

Postby simonkbike » Sat Jun 28, 2014 5:42 pm

Looked all around for this but can't seen a definitive answer.

How do I completely seal the join between the wall and the bath when I have a (pumped) shower over the bath?

I'm installing a new bathroom suite with a shower over a bath. To be absolutely certain of making it watertight I'm using a paint-on membrane on the walls and taping the vertical corner joints (nicobond system left over from a wet-room project). The tape has a rubber centre section with mesh on either side to bond into the paint-on membrane. The wet-room was also taped along the horizontal wall/floor joint before tiling. So in my bathroom:

Do I tape from the wall onto the edge of the bath - and if so How?
Or do I just membrane the wall and then silicone seal the bath to the wall.

Also, I know you should only silicone seal shower screens on on the outside, so the water can't get trapped behind the screen frame. Surely the same applies to the bath. If you silicone seal the bath to the wall, and then tile down to the bath seal between the tiles and the bath, you're creating a pocket for any seepage to fester inside.

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Simply Build It

Postby thedoctor » Sun Jun 29, 2014 8:20 am

Hi, the best product we have used for this is Aquaseal tanking tape. See link ... e-10m.html

The tape is usually applied before the membrane is painted on and overlaps the bath by just under the thickness of the tile. The tile is then cut down to the bath and this joint is the grouted, not sealed with sealant. Any water getting behind the tiles can then push its way through the grout back into the bath exactly as the shower screen principle. If you dont want to use the tape, seal the bath to the wall with sealant, then grout the tile joint as before. This is the correct way to tile all baths as it is vital the water is managed, especially in a shower situation where (if not grouted 100% correctly) water can get into the joints anywhere up the wall.

The downside to this methos is that (with movement in the bath) the grout line will need touching up every 3 or 4 months. However, this is infinately preferable to dealing with leak damage.

Funnily enough we are presenting exactly this at the Home Building and Renovation show at Sandown Prk, Esher, this weekend and the image below shows an example of what can happen if the tiles are sealed to the bath and water gets in behind them.....The damage shown is a result of an undetected faulty tile joint just under the shower head which remained undetected for 12 years !!
bathroom 1.JPG
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