Flexible additive in adhesive

[frediaz]

Can a flexible additive be used in any cementitious tile adhesive?

The supplier of the adhesive I bought told me that the adhesive is for "rigid" substrates only not for "flexible" substrates like plasterboard, which is where I am installing the tiles.

I have heard that wooden floors are regarded as flexible but have not heard this about plasterboard on studs.

The plasterboard is in a bathroom on stud walls. Yes, if I push the plasterboard with my hand, where there is no stud, it moves a little. It's 12.5mm thick. I have a wall mounted cabinet with basin but it will be screwed directly into the stud members with local reinforcement for it.

The tiles are heavy, though: ceramic 11mm thick 300x600mm.

The NHBC manual says to put a lot of reinforcement in the stud walls: noggings at 600mm distance instead of the standard distance of 900mm or so, is it really necessary to put a lot of reinforcement?

Do I need to worry?

 

[Softus]

Can a flexible additive be used in any cementitious tile adhesive?

You need to ask the additive manufacturer and the adhesive manufacturer.

Alternatively, just buy a flexible adhesive.

The NHBC manual says to put a lot of reinforcement in the stud walls: noggings at 600mm distance instead of the standard distance of 900mm or so, is it really necessary to put a lot of reinforcement?

Yes. You'll regret it if the grout keeps cracking.

Do I need to worry?

You haven't said very much about the application. Is this just a tiled wall in a bathroom, or is it over a bath, or in a shower area, or what?

 

[frediaz]

It's in a bathroom where the tiling is above a bath and there is a shower above the bath but it is not a power shower, just a mixer type. The rest is on walls where there are the basin and toilet.

The thing is, I already built the stud wall and covered it with plasterboard, before I heard about needing so much reinforcement. I did add reinforcement to the stud walls but not as much as noggings every 600mm. If the main concern about the movement of the plasterboard is the grouting cracking, will using flexible grouting help solve the problem?