Advice, losing faith in tiles..

[WetSaw]

What type of tile have you ordered? Porcelain would be by far the best choice.
I would also say that the cost of laying tiles will be more expensive than timber due to the preparation needed to the screed before you start laying tiles.

 

[macten]

Thanks for all the replies, in summary there is no reason tiles wouldn't stay down on this floor, if the tiler used the correct adhesive

Provided the laitance is removed first!

 

[Richard Nessbert]

Yeah, we ordered a Porcelain tile, they are a board shape approx 1m long and 20cm width. Made in Spain.. That's about all I know about them. The supplier said 100% suitable for UFH.

How can I ensure the tiler removes the laitance.. Honestly I've had 5 tilers here now and not one has mentioned sanding the floor.

Is the sanding somthing I could do?

 

[Flintstone]

As the others have said it sounds like the wrong adhesive has been used which is pretty bad if mapei have been and seen it and didn't make a point of that ? The laitance may have come off with the tiles either the first or second time, I would need to see some better photos of the surface of the screed to see that. There could also be contamination from the reaction between cement adhesive and gypsum floor. but either way if it is anhydrite it needs tiling idealy with a gypsum based adhesive. If none of the tilers have mentioned this sort of stuff then don't use them. Isn't @Adey1980 in your area ?

 

[Flintstone]

Just to add, sanding that screen now this far on will be a task it will be as immensely hard. I have sanded one recently that had been down years and even my diamond grinder barely touched it

 

[Richard Nessbert]

I'll try and lift more tiles tomorrow and take photos, it does seem that the adhesive has stuck solid to parts of the floor just not the hallway. Mapei came. Out about 6 years ago, I remember them saying that it was still a relative unkown and maybe concentrated to much on thr UFH rather than screen. I remember it was deff a Flexible Mapei Adhesive.

 

[Flintstone]

Mapei don't make a gypsum adhesive to my knowledge so the priming methods would have been critical.

 

[Richard Nessbert]

OK, feel like I getting somwhere thanks all.
I have 2 tilers who are taking a look next week, both have talked about sanding, priming and Gypsom based adhesive

 

[GoneGuy]

@Richard Nessbert im based in caerphilly, I won’t be able to get you and look at the floor until later in the week/weekend.
Let me know if you would like me to pop down

 

[Richard Nessbert]

Thanks @Adey1980, I, ll message you Wednesday to arrange somthing