A fine blue film in the shower... - TilersForums.co.uk | Tile Forums

Lorem Ipsum · 20-11-2007

Hi everyone. I need to tank and tile a skimmed gypsum showerbath recess and walk-in shower walls. I have Ardion 51 primer, Ardex WPC tanking kits and BAL single part flexi adhesive (with Ardex flexi grout) for the porcelain tiles. I know it is advised to stick to the same make, but this all seems good quality stuff (and I can't afford to keep spending as I am the client!).

I have had problems so far with anything sticking to the walls (previous post). Yes, they had been overtrowelled - not too shiny, but I still cleaned down, wire brushed over and primed with 3 coats of the Ardion 51, til it wouldn't soak in any more. When dry, I patched areas and corners with the stiff mix WPC and was ready to tank all with the thinner mix, when I found it peels off with the primer... Also, the dry primer can be teased up with a blade like a fine film. So I am worried if I tank the whole lot, it will do the same. Should I be priming under WPC or is it self priming?

Spoke to my builder and he said maybe the place was damp. It is part of a big openplan refurb and extension. The skim was done months ago - but the house has been closed unheated. As there was a big screed downstairs, maybe damp has got into the fabric.

So we have had industrial heaters and dehumidifiers running in the house for 10 days now. The air feels drier (been needing more tea!) and I can't put off the evil moment much longer...

Am I doing the right thing, with the right kit? Should I be priming then tanking, or tanking direct onto the walls? Will the addy work OK on the WPC? Appreciate any advice or reassurance please! Cheers.

**grumpygrouter** · 20-11-2007

Hello mate, you may have been a bit generous with the primer in my opinion. I don't recall the Ardex WPC literature mentioning priming the walls before it's use so that may be where the problem lies. Just used it myself on a job (plasterboard though) and I didn't prime the surface. Only minor problem I had was that the plasterboard had been recently taped and some of the taping filler was lifting when the wpc was being rolled on. I had better results with a large emulsion brush for application.

The rest of the materials are fine.

If you log onto www.ardex.com and search around the site you will find pdf literature for all their products. maybe do a "search" for WPC1 and it should bring up the data sheet.

Grumpy

Lorem Ipsum · 20-11-2007

Thanks for the feedback...

I had read the WPC data sheet and there was no mention of priming (or even self-priming), so as you suggested I have now contacted Ardex and spoken to their technical adviser:

WPC is designed to be self-priming. But it can still be applied to primed walls. If so it and the primer will stick together well, stronger than the sub-strait. So they will peel off together if you really try (I will resist the temptation).

The shower bath recess was primed like this, but I left the skim in the walk-in shower unprimed and will test a patch of WPC on there to see if it is stronger...

By the way, apologies to those here to see the Blue Film!

Lorem

**Dave** · 20-11-2007

Yes very true grumps mate..over priming can cause it to form a skin rather than soaking into the substrate....also some primers need to watered down on partcular substrates as well..usualy a 3-1 or 4-1 mix will do...

Lorem Ipsum · 21-11-2007

Yes, it was a 3-1 watered down mix. But working on a dry primed area last night, I still think it peels off quite easily, so I have used a roll of packing tape taking the loose off. My worry is how little encouragement it needs to peel off.

In the un-primed walk in shower, I have now wire brushed the surface. Phew. There was some PVA on there in places, which I have rubbed off too.

I wouldn't mind if I was just a slow tiler, but I haven't even got a good wall yet...