cracking grout

[andy_t_uk]

A little advice would be greatly appreciated....

I recently started my first DIY tiling job - doing my dining room floor with standard ceramic floor tiles.

It seemed to all go smoothly, good cuts and an even lay but after I had grouted it a couple of days later I realised that some of the tiles were loose and that the grout was cracking.

The surface that I was laying onto was thick weyrock floor board on a cement foundation and the adhesive that I used was recommended by the tile stockict - flexible due to the wooden floor boards.

I have had enough at looking at my failed attempt and would now like to redo the entire job - but am stuck as to what I did wrong in the first place??

 

[Andy Allen]

how solid was the floor when you tiled it ......if you jump on the floor is there much bounce .....and what make was the adhesive

 

[Stewart]

Did you tile directly onto the floor...? What prep did you do?

 

[Ian]

As above and was the adhesive ready mixed, or a powdered one that you add water to and mix yourself? Welcome along to the forum.

 

[CJ CERAMICS]

sounds like movement in the floor .

 

[kevin67]

sounds like a floating floor. the adhesive should have been a 2 part flexible, although most tilers wouldn't tile on a floating floor as there is far too much flex in it, also the floor should have been overboarded as tiling directly on chipboard is a 'no-no'

 

[The Legend; Phil Hobson RIP]

As above, to much deflection imo:yikes:sorry.

 

[andy_t_uk]

Thanks for the quick responses lads - greatly appreciated - I sealed the floor with tilers primer then tiled directly onto the weyrock.

Forgotten the name of the adhesive but it was a powdered version that I mixed myself.

In terms of the bounce of the floor - the dining room is a newly built extension with a concrete floor and large floor board sections set on top to bring it in line with the rest of the house.

Can't remember any flex in it - my first thought was that I mixed the adhesive wrong so I went out and bought some B&Q ready made stuff. Lifted the tiles that were loose and re-fixed them. But time has gone by and all of the tiles that are in the main walk way that is used on a daily basis have had the grout around them crack.

 

[Andy Allen]

was the primer P.V.A........the B&Q ready mixed stuff is pants

 

[nybor62]

floating floor or not weyroc boards are not suitable to tile on

 

[andy_t_uk]

I think it was P.V.A based - I mixed a couple of parts of it with water and painted it over the area - I purchased it from a discount tiles store after I quizzed them as to what I needed.

 

[Stewart]

Firstly, weyroc is unsuitable to tile directly to.
Pva based primers are unsuitable for tiling.
It also sounds like you have a floating floor, which the majority of pro tilers will refuse to tile on.

You need to strip floor to start with, then find out if the floor is floating or not.

 

[andy_t_uk]

I can remember the builder fixing the boards straight to the cement foundations ??

 

[White Room]

To a screed floor or concrete, could be absorbing moisture from the floor.

 

[andy_t_uk]

I think it was a solid concrete foundation and he put a membrane down and screed it - then placed the boards over it. Do you think it would be best boarding out the whole area? If so that boarding / thickness would you suggest? And what adhesive & grout?