Silicon sealant not sticking

tkimages · 15 Jun 2009

Hi all,

I've recently refurbed our ensuite and fitted a new shower. It's just started leaking, and the leak appears to be due to the tray dropping about 1-2mm when the heaviest person uses it. I used a large silicon bead (10mm) but it appears to have lost its adhesion to the shower tray and thus leaks. The tray is a glossy low profile Just 40 tray which sits directly on the floor. The shower walls are Grant Westfield Aquapanels and the silicon used was B & Q Kitchen/Bathroom.

Are there any special tips or techniques when sealing to a glossy tray? I can literally slide my finger nail between the tray and sealant and prise it up!

Any help welcome.

Tillman

seco services · 15 Jun 2009

tkimages said:
tray dropping about 1-2mm when the heaviest person uses it.

whats the tray sitting on ? what type of floor.
the tray shouldn't be moving at all

I used a large silicon bead (10mm) but it appears to have lost its adhesion to the shower tray and thus leaks. The tray is a glossy low profile

was the tray clean of any grease etc, was the silicone out of date ?
no reason why it shouldn't bond.

keighern · 15 Jun 2009

I would recommend:

1, Remove all the existing sealant
2, Clean the surfaces as best as poss with metholated spririts
3, Simulate the weight of the heaviest person by adding weight to the tray (if this was a bath I'd be saying fill the bath with water, but as its a tray, you'll need to use something else)
4, try and keep the silicone joint to the smallest possible (10mm bead not ideal but should be OK)
5, Buy a decent brand of purpose made shower silicone. B&Q is cheap for a reason and tends not to have the same adhesive and flexibility quality as better known brands (screwfix has good selection of decent gear)

In order to achieve a decent finish, I always use masking tape along the 2 edges. Apply the silicone, smooth with damp finger, then remove the tape. Leaves a nice neat, even bead.

mickyg · 15 Jun 2009

keighern said:
3, Simulate the weight of the heaviest person by adding weight to the tray

or just stand in it while you do it

get some dow corning silicone from screwfix, best stuff. Shouldn't really move but hey ho prob not much ur gonna do about that now

glasgowgas · 15 Jun 2009

clean all surfaces with meths, allow to dry thoroughly

make sure you use SILICON sealant

tkimages · 15 Jun 2009

The tray is sitting on a laminated floor, laid on top of chipboard T&G flooring.

I thought the elasticity of the silicon could cope with 1-2 mm of movement.

Wouls that telescopic sealer, Teleseal, be any better in this situation?

Thanks for the replies so far.

Tillman

dpsservices · 15 Jun 2009

had a similar problem and used evo stick serious silicon sealant problem solved

Agile · 16 Jun 2009

mickyg said:
or just stand in it while you do it

And remain standing in it for two hours until the silicone has set !

muggles · 16 Jun 2009

tkimages said:
The tray is sitting on a laminated floor, laid on top of chipboard T&G flooring.

I thought the elasticity of the silicon could cope with 1-2 mm of movement.

Wouls that telescopic sealer, Teleseal, be any better in this situation?

Thanks for the replies so far.

Tillman

Is there an insulation layer between the laminate and the chipboard? I would suspect that there is, in which case your problem is probably that the laminate/insulation combo is compressing, causing the drop. The 'proper' solution in this instance would be to remove the laminate flooring from under the tray, but I understand that this is slightly impractical (although not impossible) after you've fitted it.

A good quality silicone sealant on clean, dry surfaces will stick like poo on a spade. I use Dow Corning 785, it's never given any trouble. A 10mm bead is huge as well, try to keep that down a bit if possible, you may find that it's actually not curing fully before you use it. Smaller bead and a good 24 hours from application to use should see you through, but sort the floor as well!!

BingoBongo · 16 Jun 2009

make sure it is 1 squillion% dry

tkimages · 16 Jun 2009

The laminate floor is on 'insulation, but I'm not sure if I put the insulation under the tray area for that reason. Any way, it can't be removed. I've removed all the sealant, and scrubbed the areas where the sealant was with a good cleaner and toothbrush. I've also lightly rubbed the same areas with fine sandpaper to provide a key for adhesion. Tomorrow I'll give a degrease with isopropanol and when dry (Thursday?) I'll reseal with Dow Corning 785, if I can find it.

The bead is 10mm across the face, so about 7mm in contact with each surface.

Hope it works as it is delaying the refurb of the downstairs toilet which is directly underneath, and has no ceiling, due to leakage of the previous shower - not my fault - the builder.

BingoBongo · 16 Jun 2009

i would have a practice at smoothing the silicone if you havnt done it before

and have a few bog rolls standing by or wear old trousers

(feel free to quote and add joke along with smiley face)

or ask the builder to do it

seco services · 16 Jun 2009

BingoBongo said:
i would have a practice at smoothing the silicone if you havnt done it before

and putting shower trays in.

tkimages · 16 Jun 2009

i would have a practice at smoothing the silicone if you havnt done it before

I'm Ok at smoothing

and have a few bog rolls standing by or wear old trousers

I always do

or ask the builder to do it

No chance

and putting shower trays in.

I'll be ready next time

Cheers boys

tkimages · 16 Jun 2009

Must learn how to quote!

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Silicon sealant not sticking

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