HI there, Ok here it goes,, I am planning on laying quarry tiles on my kitchen and hall floor. I have underfloor heating, (water underfloor heating , not the coil stuff) and at the minute i have put 6 mm, plywood down this has been nailed down,and nails about every 6 inches. But the floor seems to squeek. Does there need to be a gap between the plywood as my husband has butted them next to each other. Also under the plywood is big panels of chipboard flooring,

What do you recommend, or will the tiles and adhesive stop this,, or will it cause the adhesive to come away in years to come.

What adhesive would you recommend to use?

Any advice would be great , thanks

Hi kerosene welcome along.Would you tell us the type of tile you are using?that way we can find the right adhesive to match your needs

HI, Will be using a quarry tile, Possibly Ruabon quarry tiles form CTD in newcastle.

First thing to do would be to sort the floor out, the sub-floor that is, it needs to be solid, screwed down, not nailed as the nails will work free...ish. then the overboard want to be at least 12mm wpb, primed on the underside and edges, these want to be laid with a 2mm gap between them for expansion, these also need to be screwed not nailed down at 200 - 300 mm centre's.
What were you planning on covering your pipes with ?

Hi Alan, thanks ,, The underfloor heating runs the the joists under the floor. and then the chipboard flooring,, is runing across the joists, and then the ply is ontop of that.. not sure how the floor was put down, but i know the plywood has been nailed down,, and there no expansion gaps. So really it needs to be ripped up and put back down.

Are you sure you have underfloor heating and your not just feeling warmth off the heating pipes

The way you have it, your not going to get any heat through the tile, the way to do it would be, chipboard floor screwed down, wpb on top screwed down, underfloor heating, pipes / electric. Then a slc over the pipes then tile.

HI Again, I got in touch with husband, and this is what he told me.

It is polyplum underfloor heating.

So the way it is on the floor,, you have the joists, and insulation between them, then looks as there is the tin joist mounted trays, then Wayrock flooring, and then the ply that has been nailed down. He forgot to mention how the wayrock flooring was put down.

So hopefully this will help,, as still trying to figure out how to get rid of the squeek before the tiles are put down.

Alan..new method on me for wet heating.....

Kerosene...you need a thicker sub-floor to cope with moisture/thermal expansion...or if the sub-floor is solid then you can use an isolation membrane....

I have tile a few wet heat floors in-situed within timber floors....And i have used an isolation membrane each time but making sure that the floor was solid first...

The heat from the UFH will transfer no probs.....polypipe is a well used system...

Adgesive wise then you can use keraquick with latex plus to adhere the isolation membrane and just kera quick on top....or if you go the ply route( thicker ply) then keraquick and latex plus....and flexi grout for both methods..

Thanks Dave,

Does he have to lift the ply he has nailed down , or can he apply ply on top of what he has down already?

Where can you get the membrane from,,and you are saying that can go on top of the ply that is already down, and it is put down with the adhesive you mentioned, then tiled on that with the other adhesive and flexi grout.

The ply you have put down is not thick enough or stable enough to tile to and fixed incorrectly anyway...

The uncoupling membrane is used to isolate the floor tiling from the substrate thus stopping any laterall stress from delaminating your tiles...

If you contact wetdecs he can do you are very good deal on the membrane he sells...

I think that will be the safest option , but your sub floor must be rigid first..