advice on concrete to timber floor joint - TilersForums.com

[rich.]

Hi all, we are preping a kitchen floor for porcelain tiles,
the floor is made up of 1/3 original 1930s concrete slab (3m x3m) no dpm and sat on earth, this was originally quarry tiled and seems sound and dry, although the original adhesive (sand/cement?) Is well adhered to the slab and won't be easy to remove, the rest is a new timber beamed extension (3m x6m).

The new 18mm chipboard subfloor has had 12mm ply glued and close screwed. This has left roughly 12mm to make up on the slab, our question is :- do we screed the slab and use an expansion strip where the subfloors join, or is it better to bridge the join in the subfloors with ply and screw/glue to the slab?

The join has a dog leg in it where the original back door step was.

There are units along the two side walls so a 2.5m expansion strip would suffice, although a floor without any strip would be preferable if possible.

Thanks for looking any advice would be appreciated.

 

[jimthetiler]

the concrete may be dry now but what will it be like in winter.
what ever you decide to do you will need to decouple where the tiles cross from the wood to the concrete or bond out each side
of the join so there is no tile touching 2 mediums

 

[rich.]

Thanks for the reply Jim, yes the slab will get a liquid dpm