Hi guys,
After recommending tanking in the showers, I went to start the job today and the builder, after getting a small balcony tanked, the guy offered to do all 3 wetroom floors as well.
I have included some pics below but it appears to be some sort of spray-on bitumen, apparently it took a week to dry and although not sticky now, if anything is left on it overnight it will be stuck in the morning.It is about 3mm thick but in the internal corners it could be about 8mm thick and a bit spongy. No reinforcement was used at the wall/floor junction,

Questions:
Anybody tackled anything similar?
Will this be okay to tile on and what prep would you recommend? Primer?Adhesive?
The floor screed is heated,but the heating is two weeks away,so I will be just doing the walls atm. Or could the floor be tiled as it is isolated I guess by the tanking?
Would it be okay to tank the walls in the shower and overlap the black stuff at the bottom?

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whats the name of the product if i were you id check out the specs on it as no tape or bond breaker in corners is a bit strange

tom i have never seen this one mate,but when i was younger i used to lay screed's on bitumen, the roofing guy's used to boil it up and use mop's to spread around the room's then we would lay on it when it was set!! you can buy a cold tined bitumen, maybe it is this stuff just put through a sprayer!!

sounds and looks odd,never come across it before

as JAY said be careful mate ,because you did not install it i would put -in a disclamer

i just dont see how it will be poss to tile onto that , you say the screed is heated surly it will soften the tanking, when its running

New one on me too

you mentioned the guy taanked the balcony 1st,,,sounds like hes used some sort of roof gear to do the lot

Looks like the underseal i used to spray in the bottom of cars!

I would have thought that there were suitable adhesives. Wonder how long the bitumen has to be left to cure? It probably takes a while. As for the effects of heat I don't know how much heat is produced. I know that new bitumen footpaths can get rather soft on a very hot summers day but they are black and do absorb a lot of heat. Older bitumen which has lost more of its volatile oils is more stable.

I really dont like the look of it. Its an exterior product not designed for the application its now being used. Im sure it will do the waterproofing job but is it suitable to tile on? Im not so sure.
Its OK the builder saying he will take responsibility or him even signing a disclaimer but all thet does is state you are happy to continue works on a job you think may well fail!

Who sorts out any de-bonding issues in the future, compensation in court etc etc. If it was me I'd walk, if you cant gurantee your work dont do it.

Tommy, that looks to me like Laticrete 9235 (Jay knows what the stuff is), and it would take days to dry if installed as thick as you are seeing it on your job.

There is another product that is widely used, brand name Merkrete, that looks the same.

Mer-Krete Systems

Assuming this is a tanking product made for use under tile, I'd be concerned about whether they prepped the substrate correctly before applying it, and about the lack of fabric in the corners and the load bearing surfaces.

Rob dont think its 9235 as the texture is lumpy even if 9235 was sprayed it wouldnt have that texture did cross my mind

Jay, I saw that, but thought maybe that's in the substrate.

Is Merkrete sold in OZ?

hi have tiled on to this tanking method before but only after i have screeded for floor tiles pretty much all true bitumen has some sort of oil in it so to use it on walls i wonder if the glue would stick. over here some tanking guys put a bit of wash sand in it for grip as in saying that i would put some sort of sealer over it for the walls if it will stick before tiling.hope this helps cheers

Originally Posted by Rob Z

Jay, I saw that, but thought maybe that's in the substrate.

Is Merkrete sold in OZ?

havent seen it yet any good

It's not suitable to tile directly too, the adhesive will not bond.. and possible de-lamination due to in screed heating... Bitumen isn't the best to tile to, solid asphalt floors of tiling grade are different to over coats like this.


This builder has totalled that floor.. dosey git.

All i can recommend is Impey tanking membrane, bitumen backed, so will stick bitumen to bitumen..

i have tiled on bitumen before but we tiled on it we put down a concerta screed that way we were able to get our fall for the drain i used it in san franscisco so just make sure you put a screed of a 15 mil Good luck if still not sure just put in how to tile on bitnmen on u tube

the roofing guys have messed this up for you. if you try to fix on this it will bleed through the stone or the grout. i would explain this to the contractor then walk till it relined . you will have problems if you try to do it as it is!!!

Originally Posted by Dave

It's not suitable to tile directly too, the adhesive will not bond.. and possible de-lamination due to in screed heating... Bitumen isn't the best to tile to, solid asphalt floors of tiling grade are different to over coats like this.


This builder has totalled that floor.. dosey git.

All i can recommend is Impey tanking membrane, bitumen backed, so will stick bitumen to bitumen..

Good thinking Dave, I would imagine that would be the only option. Apart from lifting the lot.

Originally Posted by gooner59

as JAY said be careful mate ,because you did not install it i would put -in a disclamer

Disclaimers are not worth a hoot,unless they have been drawn up by a solicitor who is experienced with them & witnessed.
Usually as you are supposed to be the tiling expert, ten you are responsible.If you know that something is not right then you should not tile it !

Originally Posted by jay

havent seen it yet any good

jay, they are a big player here in the market. They have a good reputation.


I've never used their stuff because I go Laticrete 99% of the time.