Tiling

[balmont]

should I seal a concrete floor before tiling?

 

[lancenotalot]

I normally give it coat of acrylic primer mainly to stop it absorbing all the moisture from the adhesive.

 

[tictic]

if its "gypsum" based you will need to sand it first, to remove any laitence, then at least 2 coats of a suitable primer.

 

[PaulTheTiler]

I have never sealed a sound concrete floor prior to tiling - only if it's very dusty / sandy

 

[tictic]

I have never sealed a sound concrete floor prior to tiling - only if it's very dusty / sandy

hi paul
i have seen a few failures in the last 18months with tile fixing straight onto screeds,without proper prep..
they have all been gypsum "anhydrite" screed, tiles just "blowing" off,

just about every house builder out there now are using this type.
its only 40mm thick to the 75mm sand/cement one, so curing time is a lot quicker.
so i always ask what type of screed it is,then sand it down to remove laitance then a good few coats of recommended primer.

just to cover my a@@e mate..

 

[Richard C]

I have never sealed a sound concrete floor prior to tiling - only if it's very dusty / sandy

tictic’s right Paul; Gypsum & Anhydrite screed contains calcium sulphate as does Gypsum wall finish plasters & most base plasters. Cement power adhesives will react with an unsealed Gypsum base & can blow the tiles so be sure & check in future.