Loose floor tiling onto floorboards

jemball

A tiler has laid our 300x600 porcelain floor tiles onto interlocking 18mm waterproof floorboards (2400x600mm with glued joints), which sit on 60mm rigid polyurethane insulation boards(2400x1200mm). He primed with PVA glue solution, used a white 'flexible' adhesive from Wickes and then grouted with Mapei Ultracolour Plus coloured grout (which we provided). The grout bag says that it is flexible?

He walked on some of the freshly laid tiles after about 12 hours to access a particular spot. We suggested that this was too early but he said that it was 'OK then as he was carefully walking in the middle of each tile'. I think he also walked on some of the grouted tiles within 2 hours.

Now the grout has cracked at some of the joints and the tiles appear to be moving (it is hard to tell if the tiles are loose or just flexing with the floorboards) This seems to be mostly where he walked but may also be on non-walked on areas which we now traffic heavily.

Before we ask him back we would appreciate some advice as to what caused the problem. Brief research suggests the following:

Adhesive not thick or flexible enough.
Walking on tiles too early.
Grout not flexible enough and should have used a latex additive.

Any advice especially on remedial measures will be greatly appreciated.

Canucklehead

Hi

I'm sure someone with greater knowledge will come along, but my first thought was the 60mm insulation.It's a floating floor and it will never be rigid enough to tile on.Just my opinion though.

Corgi Guy.

ormus

i thought it was 24 hrs minimum before any foot traffic?
think id replace the grout and leave as long as possible. ive used wickes flexible adhesive and grout on wooden floors, with no real problems.

jemball

Have you any suggestions for removing the grout, it seems to have stuck to some of the tile edges like 'you-know-what'.

tile_guru

cement based adhesive even 2 part flexi is not really suitable for ins boards on t&G... A single part flexi grout which is what i think has been used is also not flexible enough.

The PVA should never have been used... Never us PVA when tiling. An advanced polymer priming agent should be used. PVA breaks down with the water in the adhesive.

So to rectify....

Clean excess grout off with sealer and coating remover made by aquamix.

remove the grout to at least 6mm deep....

replace the grout with an epoxy grout made be BAL....

GURU

jemball

Thanks GURU. Is there a good way to remove the grout as we tend to chip the tile? Also is it OK to add BAL admix GT1 to our Mapei grout to give it more flexibility?

The loose tiles have a very slight rocking movement (less than 0.5 mm) so will replacing the grout minimise the movement apart from the grout not loosening?

Jem

tile_guru

no unfortunatly not....

you can hire a machine from hss tool hire called a fein multimaster. this will remove the grout quickly and without chipping the tiles.

i would stongly recommend you go with epoxy for the grout...

Guru

jemball

Thanks again Guru. If we have to replace any of the porcelain tiles, do we need to treat the underside of the tiles before laying them on the adhesive?

tile_guru

no treatment required..

Guru

jemball

Thanks Guru. One final question. Is there a machine to remove adhesive from the floorboards, apart from the human one with an old chisel and hammer?

BobProperty

Canucklehead wrote: »

Hi

I'm sure someone with greater knowledge will come along, but my first thought was the 60mm insulation.It's a floating floor and it will never be rigid enough to tile on.Just my opinion though.

Corgi Guy.

Given that these are 300 x 600 Porcelain tiles I'm with you on this one.

If you do go the route suggested by Tile Guru be aware that epoxy grout is an absolute pain to work with (so I'm told) in terms of cleaning off and it getting on everything and then being difficult to remove.