Leaky shower in new house - how to troubleshoot?

machofairy

We just bought a house with a shower cubicle in the upstairs bathroom. It is tiled with a basin and we discovered some damp towels underneath it. Some of the seal is also very mouldy. So far, I have attempted to remove all the seal with a pen knife but been proving difficult. We plan to simply reseal it with normal silicone. Any remaining seal that we cant remove, we will just reseal over it. Can anyone suggest what else we can lookout for to ensure it does not leak at all?
Thanks in advance.

HugoSP

DON'T even think about resealing over old silicone. You will end up with a complete mess.

Clean the old off completely using silicone sealent eater. Available from Plumbase etc. I can receomment this product. You remove as much as you can then apply this over the really stubborn stuff.

JML do a product that includes a specially designed tool to remove this. IIRC it's around £10 for the whole kit an includes silicone profiles for resealing.

TBH there are several places that shower cubicle can leak from. Do you know what the tiles are fixed onto? If it's pasterboard then this can cause problems.

If it were my house I suspect I would be tempted to rip the whole lot out and rebuild it completely.

The tiles should be fixed onto Aquapanel or similar that should itself be sealed with silicone at the joints. I often put this over the back edge of the shower tray so that water dripping down the tiles runs straight onto the tray.

The cubicle, assuming it's a glass one, is usually sealed between the fixing brackets and the tiles, and along the outside of the join between the base of the screen and the top of the tray. Cubicles are designed to train internally so anyone sealing the screen/tray interface on the inside will simply ensure that the water trickling down the profiles will run down the outside of the tray and onto the bathroom floor.

Special attention should be paid to the shower trap and the plumbing underneath. Just make sure these are dry.

This may seem a bit belt and braces but the above should give you a few ideas as to where the leaks my be coming from. Perhaps the best wasy to test the shower is to point the rose at certain areas and see if you get trickles of water...

PROFESSIONAL_LANDLORD

Tip when applying silicone =

Apply masking tape to the shower tray /bath ( 5mm out from wall )

Apply masking tape to the tiles ( 5mm up from the tray / bath )

Keep the tape straight

Apply silicone, run your finger along the silicone to smooth off

Remove tape immediately

MUCH NEATER

Mutton_Geoff

To add to PL's tip, dip finger in soapy water first, makes a smooth finish. Remove tape within 5 minutes if not immediately. It'll be a mess if the silicone sets on the taped edges.

ozskin

unlikely to be just silicone esp on new house ,have seen so many of these, if its new house and nhbc registered get them back take it all out and start again

machofairy

Thanks all for the advice.
The shower has 3 sides tiles, and the door is glass. I have so far stripped as much of the seal as I can with a penkinfe. I will look for that seal eater tomorrow. I am unsure how the tiles are attached to the wall. Looks like they are just stuck straight on. Could it be possible that it is leaking through the grouting? If so, does simply putting a new layer of grouting over the existing grouting help? Plumbing underneath looks dry. It a 50 year old house. The shower is on an elevated platform above wooden floorboards which appears to have been plastered over. I dont understand fully about the masking tape bit. Do you mean .... apply the tape, not between the tiles, but just above where the tiles meet so that the silicone is neat and does not over-run into the tiles too much? If so, is this purely for cosmetic value?
Thanks in advance.

HugoSP

It is quite possible that the water is getting through the grout.

The way I would cure this is to rake out and regrout, remove the tiles and retile, or you my consider tiling over the old tiles. Don't just regrout over old grouting. You can get tiles so cheap these days it's hardly worth salvaging the old unless they are something special.

Tiling over old tiles is quite acceptable, and it can provide another layer of defence against water penetration.

PLs tip about the tape - I think you've understood it properly, and it is for cosmetic pursposes but it does give you a neat job.

Mutton_Geoff

In my (new build) house, the builders fitted the shower door before the tiler grouted, so the grout ran up to the edge of the shower door frame which was then siliconed. There was enough of a gap (not visible) in places to let water past which then ran through the ungrouted gaps in the tiles behind the door frame (about an inch) to then leak downstairs into the lounge. It was a b*gger to find, but easily sorted once traced.

machofairy

It appears that the problem may be quite serious ... I lifted the vinyl around the shower and there was a plasterboard on top of the floorboards. The plasterboard has black damp stains around the two corners of the shower, stretching up to over a foot wide. I have not lifted the plasterboard to see what the state of the floorboards are like. However, immediately outside the bathroom, on the other side of the shower, I can see very small traces of the black damp stain on the floorboard already. So far, there are no traces of any dampness or stains on the white ceiling downstairs.
Is this something that we can just let it air out to dry?
I am tempted to just get the shower cubicle ripped out and install one over the bath, before the problem gets any worse.