Tile grout blown, tiles easily lifted up. what's the problem?

[Brendan1]

Hi,
I have numerous problems with tiles laid about four months ago.
Problems include:Grout coming up; tiles moving up and down; hollow sound when you step on a tile.
I lifted a tile. It came up very easily - in one sharp blow of a hammer! Underneath is tons of grey stuff that has cracked - presumably the glue.
What has happened? Has the glue not worked ?
What should i do to rectify this problem?
Thank you for any advice.
Brendan

 

[Matt Bott]

Looks like the adhesive has failed is it damp at all ?

 

[WetSaw]

What is the floor under the tiles?

 

[One Day]

What is the floor under the tiles?

I'm guessing 6mm ply.

 

[Blunt Tool]

Looks like the adhesive was already too dry as it has not bonded onto tile or ply. Best to take up floor, if tiles all come up like that they can be used again just clean edges. Give sub floor a good coat of SBR bonding, and a bag of slow set flexible S1 cement based adhesive ( Mapei etc ) from your local tile shop. Grout with a flexible grout

 

[Bond]

As noted above. Adhesive failure! may also have dampness issues. Is this a ground floor entrance?, if so, I would check the structural integrity of the floor joists and for potential sub-floor dampness problems. Only way to know is ,take up the tiles, etc and have the area inspected.

 

[Time's Ran Out]

Your not having much luck are you.
That's 2 threads started both with tiles coming up. This hallway and a bathroom.
I'd get the tiler back!

 

[Glynn]

It could be that the adhesive has not been serrated out evenly and the tile not back buttered, also the adhesive looks dark like it is still damp. Could there be damp there? Is there any UFH?

 

[Brendan1]

Many thanks for your replies.

You could be correct about the possibility of damp. We are having to install a damp course into the adjacent walls in the front hallway. Dampness runs half way up the walls.

Saying that, the joists and noggins weren’t damp when the tiles were installed.

Plus, the builder used cheap plywood. Some of it (6mm) went onto floor boards. The remainder was 18mm ply where they were no floorboards.

Is it just damp that would cause the adhesive not to bond to the tile or ply?

Some recommend I don’t use plywood. Do you agree?

What does SBR bonding do (in layman’s simple terms!)?

 

[One Day]

I Win! 6mm ply. That square crazing on the adhesive bed gave it away.

 

[One Day]

To answer your original question though, how to rectify it. It all needs taking up. Replace the ply with something stronger that's not 6mm ply. if you've damp issues, I'd suggest overboard the floor with 10mm wedi board. Or ditra membrane.
And most important, get a tiler in who knows how to prepare properly!

 

[Brendan1]

Thank you!
So, 6mm is too thin?
if so, what material and mm width do you recommend? I heard backer board is the best.

 

[Brendan1]

is wedi board the same as backer board?

 

[Brendan1]

another issue is that the tiles slope downwards as they approach the front door!
how would i straighten this? is screed the correct material?
Thank you!

 

[Bond]

Many thanks for your replies.

You could be correct about the possibility of damp. We are having to install a damp course into the adjacent walls in the front hallway. Dampness runs half way up the walls.

Saying that, the joists and noggins weren’t damp when the tiles were installed.

Plus, the builder used cheap plywood. Some of it (6mm) went onto floor boards. The remainder was 18mm ply where they were no floorboards.

Is it just damp that would cause the adhesive not to bond to the tile or ply?

Some recommend I don’t use plywood. Do you agree?

What does SBR bonding do (in layman’s simple terms!)?

SBR, is a primer and admixture , which increases bond strength and flexibility.