Sealing plastic shower tray

[zeroseven]

I have two plastic shower trays. On both I have water getting between the tray and the base of the bottom tile. Once it starts the syphon effect draws water through and it pours through the ceiling below. I have replaced the silicone sealant several times, but after a few weeks at best, holes appear in the sealant and / or the sealant parts company from the tiles and the water goes through again.

I have put wooden blocks under the tray to stop bodyweight from flexing the tray. Each time I reapply the sealant I clean the surfaces to a fanatical extent, I've even used strong solvents.

Nothing seems to work. It seems incredible that there is no lip that goes up behind the bottom tile to prevent the water getting through.

Short of switching to porcelain bases, is there anything else I can try??

 

[breezer]

as you say it is the weight of the person standing in the shower that is causing it to move, i had a similar problem with a bath. I solved it by putting loads of silicone down the gap, waiting for it to cure, then putting a decorative layer on top.

You could also try a kitchen "sealant strip" and silcone that into place at an angle (a bathroom stip for me was too narrow) Also I would recomend genuine silicon not an "own brand"

 

[curtly]

I had a similar problem with both a bath (sealant coming away) and a shower cubicle with a leak, both were plastic and suffered from flexing, more from myself than the wife as she liked to tell me !!!!!. I solved it by using a PROPER silicon sealant (£6 - £8)...see breezers post....... but the most important bit is getting the area clean, my bath was new so the only thing i did with that was to tighten the support as much as possible and fill the bath with water, seal it, smooth it and let it set, empty the water. The shower was an a**e to get clean, everytime i sealed, it leaked because of the natural white scum that settles on the surface, in the end it took sugar soap and a lot of elbow grease to sort it but it was worth it because the finished surface was alot better for silicon adhesion, if you've got a big 'flexing' problem then ideally you could do with some weight in the pan while its settling but for obvious reasons this is pretty impracticle, unless your missus has got a long bordom tolerance !!!