tiling over kitchen floor tiles - latex or not?

[diamondrobbins]

Hi all,

Wonder if anyone could give me a bit of guidance. I'm tiling over an existing kitchen floor, about 20% of the previous tiles were cracked and sounded hollow, so I've removed them and filled in with a sand/cement mixture.

I intend leaving this to dry thoroughly (will 3-4 days be OK- fill depth is about 10mm), but on checking the levels of the floor, I've got about 3-4 mm of deflection within the tiled area. Would it be best to use a latex self-leveller, would this be OK over existing tiles?

Also, I have some Wickes acrylic floor primer - would this be beneficial before and after the latex?

Many Thanks

Dave Robbins

 

[kilty55]

hi diamond,just a few questions what is the type of tile currently down

also what is the substrate

the 20 percent tiles you removed were they randomly broken or were they in larger areas?

 

[nybor62]

this dont sound good pal , 1st thing why were that amount of tiles cracked, is this a timber floor and also is it a floating floor , i would remove all the tiles 1st
and check the soundness of the floor if its floating floor then its a no brainer imho

 

[kilty55]

sorry just read your floor has deflection as well time to remove exisitng floor me thinks

 

[diamondrobbins]

The original floor is concrete.

The tiles that have been removed were in the most used areas, they sounded hollow and when I removed them they didn't appear to be very well bedded down, the adhesive ridges on the back of the tiles were quite deep with lots of air in between them. (I could be wrong, but I suspect there should have been more of a flat face to the adhesive where the tile should have been pressed down into the cement bed)

Either way, I'm pretty sure the tiles are now firmly fixed.

Sorry, I think I've confused people where I said the was a deflection, what I meant was 3-4 mm of level difference (dips and bumps).

Many Thanks,

Dave Robbins

 

[diamondrobbins]

Also, the original tiles were ceramic.

 

[SJPurdy]

What do you mean by deflection? Most of us would take that to mean the floor is moving up and down as you walk over it eg a poorly supported wood floor that is unsuitable for tiling. Or do you mean that the floor is deviating from level by a few mm?

I'm puzzled by why if 20%of the floor was loose and been taken up you didn't take up the rest - i think most tilers would have to get back to a flat substrate rather than filling in with sand and cement which i wouldn't advise as it will be to thin to bond/set properly in my opinion.
You can use levelling compounds over existing sound tiling but you will need to at least use a suitable primer (eg epoxy - check with manufacturer as to suitability for purpose) and maybe abrade the surface of the old tiles to provide a key.
I think that you may still be best (assuming you have a solid-not deflecting floor) to remove the old tiles and your sand/cement patches back to the original substrate; level this up with SLC, and then retile.

 

[DHTiling]

Hi Dave, your best job is to remove ALL the tiles and start with a clean substrate.. SLC to make it flat and then tile with new tiles onto that...

 

[diamondrobbins]

Thanks everyone for all the advice.

Dave