what sanitary silicone sealant to use in a bathroom

[maxim naumov]

hello everyone

I am looking for recommendations on what sanitary sealant to use to seal around a plastic bath and also a tiled corner formed by a brick wall and and a dry wall. this area will be used for the shower.

I looked at the screwfix catalogue and found:

1. dow corning sanitary seal (not sure how well it prevents mould growth)
2. dow corning 786 (again, not sure about mould and modulus unknown)
3. dow corning 785 (high modulus)
4. uni-bond anti-mould (ice white?)
5. evo-stik sanitary (water-based!?)
6. some other unknown brands from the same catalogue

I'd be grateful for any recommendations and experience shared. I don't care much how expensive it is, as long as it lasts and doesn't turn dark or cream. the bath is quite expensive and I don't want to ruin it by re-sealing it every few months. AFAIU, for the bath I need low modulus (high movement) and for the wall it shouldn't matter much.

also, I tiled from the bath upwards and the walls are covered with moisture-resistant plasterboard. I was planning to put a bead of sealant between the bath's side and the plasterboard wall, and also fill the cavity formed by the bath, tiles and the wall. how do I make the silicone stick to plasterboard? paint/prime it first? how?

thanks very much in advance.

/max

[DIY]

My experience with acrylic baths is that if there is flexing between the bath rim and the wall surface then whatever type of sealant you use will fail eventually due to the movement caused each time the bath is used. However, if your bath has been mounted on a wooden supporting frame, especially under the rims against the wall(s), so that flexing is minimal or even absent, then a high movement silicone sealant might last. An alternative is to use a Teleseal;

. Mould growth can be inhibited; I assume that's what they mean when they claim it can be prevented!

Regarding your last paragraph, which I don't fully understand, if this is out of sight then you could use a clear silicone sanitary sealant - it will stick to anything.

[John Rumm]

For some background and application tips have a look at:

I looked at the screwfix catalogue and found:

That's what the sanitary bit is all about.

As long as you don't expect the bead to accommodate movement of more than about 10% of its size it ought to be fine. Leaving enough gap between tiles and bath to get a good key helps as well.

It will stick anyway, you could give it a coat of 1:1 PVA and water and then let that go off to give the plasterboard a moisture seal.