Movement in Bathroom Tiled Floor

[randymch]

Just two days after Mr Bathroom Installation Chappy completed his work (and got paid) I notice grout coming up from in between my lovely new bathroom floor tiles.

Closer inspection confirms there is movement when you walk from tile to tile so I took up the hallway carpet to see was base layer was applied between the tiles and the floorboards:

As the photo shows, he's used a three-ply of approximately 6-8mm. Now, I'm no expert in these things but thought you'd want something more substantial between the tiles and floor boards?

Can anyone please advise as to the minimum type of layer you would lay on top of the floor boards?

Should I ask that he re-lay the entire floor (which is gonna be a pain in the backside as his lowest wall tiles are cut to sit on top of the edge of the floor).

In fact, any advice is very much appreciated.

Cheers in advance.

 

[Richard C]

The must be no perceivable movement in the floor & the sad news is that your tiling is going to fail very shortly I’m afraid. British Standards & tile adhesive manufacturers specify 15mm WBP for ply overboard; in most cases & depending on the floor joist size/pitchy/span, it’s generally recognised 12mm is sufficient for light use/traffic areas such as bath/shower rooms but kitchens/hallways etc are classed as heavy use/traffic area & 15mm is advisable.

Using a 6mm ply over board is just a joke & it’s doomed to early failure I’m afraid. Do you know what the original floor is made of? Chipboard is about the worse base you can get & thicker ply would be necessary. Personally, I won’t over board it & would replace it, thickness depending on the joist & floor rigidity.

I can also see a gap under the tile edge; floor tiles must be laid on a solid bed thick bed adhesive using the correct trowel, there should be no gaps under the tiles or they will crack. By not observing BS & adhesive manufacturers recommendations, your “chappy” will have voided any warranty on the adhesive/grout.

IMO, your man is not a tiler but a chancer; does he have a horse by any chance? If he’s done the initial job like that, you’ve got to ask yourself do you really want him back but he certainly couldn’t make it any worse I suppose