Tanking

[samohtom]

Hi. I wondered if anyone's had this issue with tanking before? After applying a certain tanking kit featured on a youtube ultimate handyman video, I peeled off the masking tape I'd put along the edge of the bath...to find in places the tanking membrane peeled off the wall too (see below).
I followed the instructions - two coats of the tanking primer with drying in between, 2 coats of tanking with drying in between. Wall is bare plaster that was wiped down with a damp cloth before I started. I've now ripped the lot off, which was depressingly quick as it came off in large sheets:-

Untitled

• samohtom
• 18 May 2015
• 1

Untitled

• samohtom
• 18 May 2015
• 1

I'm pretty sure tanking should stick to the wall better than this? I think the primer's come away with the tanking, as the suction is back/the wall looks like it hasn't been touched once peeled off.

Thanks

 

[ree]

Remarkable. I've never seen that before. Then again i've very little knowledge of such liquid tankings. You are lucky in a way, what if the tanking had peeled off with a full load of tile?

Check the use by dates on your containers.
Did you follow instructions?
Was all suction taken up before any primer? Or would that be against instructions?
Why tape the bath tub rim when the tanking can be wiped off?

Maybe contact the maker of the tanking and see what they have to say.

How do you intend to proceed?

 

[rarara]

also tanked recently - on top of newly plastered/SBR'd wall and have found that the tanking membrane is very prone to nicks/holes with the likes of masking tape or the edge of a tile offered up if i'm careless never attempted to see if i could peel the whole lot off, perhaps mine would have done that too if i tried how long had you left the plaster to dry?

i think its just the nature of it - to be flexible enough it means it isn't very tough. never really considered how this would relate to its strength to hang tiles off

 

[samohtom]

I sent a sample to the manufacturer and got this reply:-

'The back of the sample looks very dusty which has obviously affected the adhesion.

This could be for one of 2 reasons:

The primer has been applied to a dusty surface thus preventing it from penetrating the surface, or the wall is so porous that the primer has been sucked straight into the wall leaving a dusty surface preventing the membrane from adhering.

Re priming should remedy the problem, but it may be wise to carry out a water test before applying the membrane to ensure the wall is sufficiently primed.'

I don't think it's the former as I wiped down the wall with a damp cloth before priming...I could believe the suction thing though. The wall was plastered maybe a couple of years back but I've only now got around to doing the bathroom, so it's had a long time to dry. Manufacture dates are only a couple of months ago so fine there, followed instructions as far as I know. I've sent them another e-mail to check what they mean by the water test, and I'll try repriming and testing a small area with several coats and then tanking it to check I can get it to stick properly before I do the whole wall...fingers crossed!