Screed Floor

[Ajax123]

hi guys

i have the same problem me 100m2 of classic travatine have also been laid on a gyvlon flow sreed floor by my tiler using a flexi rapid set adhesive we aloud the currect drying time and more, 1mm per day, my problem is that the floor was not primed before they were fitted and are now all coming loose after 6 weeks being down, i have come to terms with the fact they need to all come up and new ones relaid (my stairs and kitchen have been fitted on top of the tiles and i am hoping to take them up around them so with the adhesive already fixed on the back plus new adhsive the old ones i take up will be to proud when relaid) my problem is whos to blame, i told my tiler it was a screed flow floor and he asssumed that it was like any other concrete floor and that no primer would be needed,having read the previous posts i have gone back to the tiler saying it is good practice to prime first anyway and now he is trying to say he thought the floor had already been primed and that it was ready for him to tile on straight away, this is a mess, he is clearly trying to get out of this being his fault, i am a reasonable man and this sounds like an unfortunate mistake by a good tiler one that i have used many times before, he was not aware of the material that he was fixing too, i have not yet paid him for the work he has done, he is saying he will relay new ones free of charge and that i have to take up the old ones prime the floor and buy the new ones, is it me or does this sound like a bad deal if so can you tell me what a good one should sound like, i am trying to get a tilers perspective on this matter..

many thanks in advance

All screeds should be primed prior to fixing tiles. Anhydrite is no exception.Indeed it has a very absorbant surface so will as one previous poster said "suck the life out of the adhesive. If the screed has a laitance this should be sanded off and the dust removed to leave a clean dry dust free surface. If a cement tile adhesive is to be used then I would suggest a water based epoxy primer or at least 2 to 3 coats of good quality acrylic. This should be one that does not reqire diluting IMO. the epoxy will prevent the migration of sulphates through the primer thus preventing ettrignite reaction. Alternatively you could use a gypsu based tile adhesive although there are not many of these about in the UK yet. . there are several of these in France where much more anhydrite is used.

 

[TJ Smiler]

Hi all, i know this thread is old now but it's still very interesting. I viewed a job yesterday where i am slightly unsure what the substrate is. The customer had builders in to screed the floor but has since fallen out with them over money, i asked if it was sand and cement or anyhydrite but he has no idea and the builder refuses to talk to him. My initial feeling was that it was traditional sand/cement but it looked very smooth and if i'm honest like a job very well done by the builder (they fell out over money on the roof and nothing to do with the screed) i don't want to take any chances so is there anyway or little tests etc i can do to find out if it is Anhydrite? it was also only layed about 5 weeks ago and the lighting was very bad so it was hard to get a good look at.

Like i say it appeared smooth to both the eye and to touch and i couldn't feel too much dust on the surface. i couldn't really tell if it was light grey or dark grey either!!

Any advice please?

 

[Ajax123]

Hi all, i know this thread is old now but it's still very interesting. I viewed a job yesterday where i am slightly unsure what the substrate is. The customer had builders in to screed the floor but has since fallen out with them over money, i asked if it was sand and cement or anyhydrite but he has no idea and the builder refuses to talk to him. My initial feeling was that it was traditional sand/cement but it looked very smooth and if i'm honest like a job very well done by the builder (they fell out over money on the roof and nothing to do with the screed) i don't want to take any chances so is there anyway or little tests etc i can do to find out if it is Anhydrite? it was also only layed about 5 weeks ago and the lighting was very bad so it was hard to get a good look at.

Like i say it appeared smooth to both the eye and to touch and i couldn't feel too much dust on the surface. i couldn't really tell if it was light grey or dark grey either!!

Any advice please?

If you cannot find out then my advice is treat it as if it is anhydrite anyway. Everything that should be done with anhydrite should also be done with sand cement but often isn't. Therefore what you do with anhydrite works for other screeds. You could also use a neutral adhesive like kerakoll h40 ideal which will stick to either.

 

[TJ Smiler]

Kerakoll h40, never heard of it but will check it out. Thanks mate