# Forum Home Renovation Tiling  Tile adhesive over waterproofing

## Prospector

Hi all
So the last of the glue I used for most of the floor went hard and I rushed out and bought 'Davco Grey Pot' to finish the last part. I bought premixed cause I had bad experiences trying to mix powder glue. 
So now I'm up to the walls in the shower recess, and I find this tiny writing right down the bottom on the back that says 'Do not use over impervious surfaces, ie. waterproofing membranes'. :Doh:  :Doh:  :Doh:  :Doh:  :Doh:  :Doh:  :Cry:  :Cry:  
Naturally, I don't have waterproofing in the shower - not. So is this a blanket disclaimer statement they all make? Or should I really not use the 95% full unreturnable bucket? :Annoyed:  :Annoyed:  :Doh:  :Annoyed:  It's crap and annoying but I do want to do it right.
Thanks for your thoughts....

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## Batpig

Dear Prospector, 
I just had a read of Grey-One-Pot's "technical data sheet" over at the Davco website (http://www.davco.com.au/images/produ...0One%20Pot.pdf), and it not only looks like you're not really allowed to use it over Waterproofing Membranes, but it also sounds like you're not supposed to use it in Shower Bases (just in case that's what you've done with it prior to now... :Frown: ). Since the stuff is a curing-chemical type of product, as opposed to a setting-concrete sort, I guess the problem could be either the inability of the solvent in it to evaporate away when used on non-porous surfaces, or perhaps a chemical reaction with the Membrane itself. Unfortunately I couldn't see any reference to using a Davco additive of any sort to get you out of jail in such a situation. 
I wouldn't consider all to be lost, however. Have a read of this other Thread from a few years back that tackles the very same issue, without arriving at an altogether negative consensus: http://www.renovateforum.com/f205/sh...ghtmare-53880/
(How's my memory?... Not bad, hey?... :Wink: ) 
You'll obviously have to weigh up the risks yourself, but your main problem might lie with the effects of moisture if you've used the stuff in the Shower's Base. Davco's Technical-Helpline (Ph. 1800 653 347) is manned by real people who are pretty helpful when it comes to this sort of thing... 
Good Luck with it,
Batpig.

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## Oldsaltoz

Two weeks after I waterproofed an upstairs bathroom the tiler called me and what was in my waterproofing that prevented it curing based on the fact that the tiles in the bathroom were still moving but the ones in the toilet were fine. 
I met him on site ti inspect the problem, sure enough he had used pre mix glue and because it was trapped between tile and membrane it could not breath, just the same condition that stops it going in the drum. 
Ah he said, it that is right why has worked perfectly in the toilet. I had to remind him that I advised him to waterproof the toilet but he advised me not to. I asked if had sheeted over the timber floor, he replied no. He was not a happy chappy when I advised him to take the tiles up, sheet the floor and re lay them before thay started falling off because of the timber swelling and shrinking with humidity and moisture. 
I would like to advise that having got yourself into a position of pre mix glue under tines on a membrane, do not add a highly waterproof grout, this will only improve the seal and not allow the retardant in the glue to escape. 
Blame the supplier if you specifically asked for a suitable glue over a waterproofing, or blame the tiler, he should know and would know if was ever properly trained, this does not include 'Parrot fashion'. 
You pay peanuts you get monkeys. 
Good luck. :Smilie:

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## Prospector

Well that's good to know. Thanks Batpig for that link, dig as I may I didn't find that! I have used the premix for the few tiles under the toilet (over the waterproofing), and it took it's sweet time to go off. Instructions said 24hrs, and it was still a bit soft. All good. 
I will get some new stuff for the shower then. But all is not lost, I still have the vanity, laundry tub, skirting, and even a kitchen down the track if it's still usable by then - none of which have the waterproofing issue. 
Thankyou once again for your unending guidence forum members!

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## Prospector

Just came back from Bunnings, I had a look at some of the other premixed adhesives out of curiosity, and they said 'Caution: Not to be used on low absorbtion surfaces or waterproofing membranes due to prolonged drying times.'

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## LordBug

How intriguing. I used the Dunlop stuff (I knew a rep who was working for them at the time so I was able to get it far cheaper than what Bunnings charges), and didn't read anything along those lines on their adhesive, and it set fine on the waterproofing membrane. I might have a look at one of the empty tubs to double check. 
Otherwise, no problems two years down the track from using stuff from the same company.

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