Grout coming out and crackling noise under some tiles

[Andy Allen]

No the adhesive was spread on the floor and the whole area of the tile was covered with reinforcements to the edges as needed.

So he spread adhesive on the floor using a notched trowel then put blobs of adhesive onto the back of the tile...?

 

[Flintstone]

This isn’t an error due to not back buttering. It’s a problem with the bond to anhydrite. It’s a solid floor so if there is any grout coming out or any movement at all in a tile then the tile has come loose.lift a tile and look what’s happening, I’m sure it will be adhesive stuck to tile but not the floor. What were the moisture readings? What did he use to sand the floor? 3 weeks before tiling one of these screeds is not a long time at all, they can take many months to dry out.

There’s some good gypsum based Adhesives out there, not sure why he didn’t use one!

 

[Flintstone]

I don’t use primer g but perhaps someone who does can confirm, on gypsum based surfaces you need a neat coat of primer to create a barrier between the gypsum and the cement based adhesive,

 

[Andy Allen]

Andy......re- Read the ops post..
This is the second time it's been tiled... .

 

[Flintstone]

Yeah I know!

 

[Andy Allen]

Yeah I know!

So how do you know it's not a bond problem due to not back skimming?
Also by the second time it was tiled I imagine the floor was drying for more than 3 weeks..... Plus with the heating being turned on it would force dry the floor......
Still could be wet though... Lol
Need to lift a tile really.....

 

[Flintstone]

I’ve known of screeds still being wet after 8 months even with ufh!
I would be very supprised if the tiles came up clean with the adhesive stuck to the floor, after all the failed anhydrite floors I’ve seen personally and online, always come up leaving the floor clean.

 

[Sachin Parab]

Hi Andy,

To answer your initial question yes he did put adhesive on the floor using a notched trowel but not sure about dabs at the back of the tile as I didnt see him do that.

 

[Sachin Parab]

Hi Localtiler,

Thanks for your input into this. As Andy has mentioned the screed has been left to upto 7 weeks to dry considering it was tiled the second time. The hygrometer reading was within normal limits (cant remember the exact readings, but I was there when the readings were taken). He took the reading from different areas downstairs.

When we lifted the tile the first time (when about 90% of the tiles were actually moving), the adhesive was stuck to the tile not the floor. Hence after discussion with technical team at Mapei the primer was used.

This time around about 15-17 tiles of the total 180 odd tiles are showing signs of grout loosing and crackling sound is being heard under 3-4 of them.

I am unsure why this should be happening if it was a bonding issue with the anhydrite. I would have expected all of them to have started moving by now. May be it will happen in due course I am not sure, but the first time it happened in a matter of a few days of turning the UFH on.

 

[Qwerty]

Got any photos with close ups?