Silicone not bonding

[Steven Campbell]

Hi guys I recently had a shower tray installed (Bathstore, low profile, plastic I presume) and had new tiles fitted round about it. The floor it all sits on was particle board. On top of this was some sheet ply and underfloor heating insulation boards The under floor heating element and then the floor tiles. The shower tray has been sealed with silicone round the outside but it only seems to bond for a few weeks and then seems to peel off the try at certain points.

I think maybe either the tray moves slightly when in the shower or the tiles move slightly and it is enough to break the bond of the silicone.

Is there anything I can use or trick to make the silicone stay bonded?

Thanks.

[Tim Watts]

Steven Campbell ( [e-mail]) wibbled on Wednesday 26 January 2011 12:27:

Silicone's "peel strenght" is relative weak as the material bends so easily

- but if it is virtuall falling off by itself you my have a poroblem.

How well was the tray cleaned before siliconing? And is the particle board moisture resistant - I thought someone mentioned that such board was sometimes waxed to achieve this - which would make for a poor bond.

Or is the silicon bonded to the tiles?

In the worst case, scrape it off, clean with a degreaser (I use IPA which is usually strong enough and rarely a risk to plastics) and reseal with a quality silicone (Mapei, Siroflex or Dow Corning for example - I have had excellent results with all of these).

[Steven Campbell]

When I say falling off, I mean if you look along the silicones line you can see a handful of sections maybe a couple of inches in length where it has peeled away from the shower tray. The builder has done it twice now although come to think of it he used some sort of wipes to remove the old silicone and only left it a few minutes so maybe it had some of the residue on the tray and that's why it hasn't stuck well. It seems to have stuck to the tiles ok but then they are on the floor so I wouldn't notice it as much.

Sheet ply was put over the particle board for the tiles to go onto but then I changed my mind and wanted underfloor heating hence all the different layers.

I'll try a decent silicone.

Cheers.

[Mr Pounder]

Try scraping the old stuff out then putting the weight of a person on the tray ---- hmm. Then reseal. Sealing a bath is supposed to be done with the bath 3/4 full of water.

[Steven Campbell]

I thought of this but would it not have the opposite effect to filling a bath 3/4 full?

[John]

Try a product that sticks and seals. I think No Nails do a combination product. It's intended for sticking stuff in wet environments. Worked quite well sticking quadrant tiles around our bath.

John