Re: Seal between tiles and bath?

GB wibbled on Sunday 25 October 2009 22:43

Have you got > 3-4mm gap and less than perhaps 10mm? If so, why not just use silicone (a decent one not cheap rubbish)? That's what I've done - I made sure to leave about 5mm gap +/- so I can get a decent plug of silicone in that won't (hopefully) fall off the first time the bath flexes.

Yup, works well - we've had that stuff in use for over 10 years now.

Alas I'd have to say it's called utter rubbish. Sorry to disagree with the two respected advisors, but IME it's completely useless. I've replaced loads of it.

Best solution IMO is an 'L' shaped plastic profile - B&Q sell it. Two types available, one fits under new tiles to provide a seal & the other fits over existing tiles & is best fixed with something like Evostick Nail & Seal.

On Mon, 26 Oct 2009 00:44:33 GMT, "The Medway Handyman" had this to say:

Isn't that a Good Thing?

Yes, if someone else has installed it & I get paid to replace it. No if I install it & get called back because it leaks.

The answer to that is to supprt the bath properly. One, with a batten around the wall and two, by reinforcing the usually inadequate baseboard.

Andy C

I agree - preventing movement has to be the first step. My bath has had a bead of sealant for about 12 years and it is still like new, Strips seem to attract mould and trap any damp that gets in.

Having found dry rot when pulling out the old bath due to leakage at this join (fortunately not serious in this case), I was rather concerned to make sure that couldn't happen again. I put a wide strip of silicone along the two bath edges which butt against the wall and slid the bath into place. 7 years later, nothing has leaked through the join. On the visible surface, the join is simply grouted, along with all the tiles.

Mind you, I dread the day I have to remove the bath...

Andy Cap wibbled on Monday 26 October 2009 08:27

In my case, already done - 3x3" and 4x2" all round except the front - and that has its own 2x2" frame bracing it to the floor and to carry the bath panel.

There is still a tiny bit of flexing here and there - it's impossible to completely eliminate it with plastic.

I did similar. Waterproofed the wall. Put a bead of silicone on that before putting the bath in place. Then a bead of sealant into the gap. Then tiled. Then applied the final bead of sealant. I have just redone that after about 10 years.

Andy C

I always fill the bath at least half full before I start and leave for for 48 hours after.

I did that. BAL WP1 on wall, and the 3 stage silicone approach. I thought "no chance any water will get past all that"! Also, loads of timber under the bath to support it. Simon.

sm_jamieson wibbled on Monday 26 October 2009 10:08

I used SBR diliuted 4:1 - which was on the BAL Greenstar data sheet as an alternative to WP1.

Oh, I go a lot further than that with a cheap bath. Slabs of MDF stuck on with car body filler and a full 2x2 frame. And a bit more wood backing up the base if there is any sign of flex.

expanding foam is also useful.

I didn't waterproof the wall (bare new plaster). However, I did use a waterproofing grout additive, BAL admix GT1, IIRC. Very expensive, but a little goes a long way. (Gave the rest of it to my dad, and he's done another very large shower enclosure with it, and still had plenty left over, although it's now well past its use-by date.)

So far, there's no water staining on the bare plaster under the bath. The bath is actually mainly used with the fitted show over it, so loads of water runs down the tiles into it. Also, there's no staining of the grout at all, which is what I hoped the waterproofing grout additive would prevent. I would certainly use that again.

I filled the space under the chipboard base of the bath with expanding foam, as suggested on here a couple of years ago. The bath is still as firm and stable as it was when the foam set.

I used a suitable sized cardboard box (sides only) to contain the foam, and used Visqueen over the floor to ensure that removal of the bath won't be any more difficult.

The secret to any bath / wall sealant is to have absolutely no flexture between the bath and wall, from when the bath's empty to when it has

I think it is made by 3M.

The Medway Handyman pretended :

It is, if you do not apply pressure to it with a roller. I tried various ways to get it to stay stuck, but the only thing which worked was one of those decorating rollers - a small wooden roller with a handle. It needs enough pressure placed onto it, that it forces the sealant out then it stays put. I installed it over 15 years ago and its fine.