Having failed to pay proper attention during earlier discussions I
wonder if someone can kindly highlight the conclusions?

Early next week I hope to be laying polypipe under floor heating and
will shortly thereafter be badgered by my builder for a decision on
flooring so he can lay screed.

I doubt there is sufficient space to use battens or plywood and yet
match existing floor levels so gluing direct seems the obvious route.
This also reduces the *insulation* effect of the flooring.

Flooring seems to come in a huge range of thickness and a variety of
substrate materials to say nothing of the fixing options! Entrance, hall
and shower room are likely to be in 300 x 300mm ceramic tiles which,
having measured some existing, are about 13mm thick: including fixing.

I suppose minor variations can be taken care of at thresholds but is
sub-15mm engineered wood going to do the job?

What happens to expansion/contraction with glued fixing?

Can you still get that very thin door matting to drop in a 13mm deep
well?

regards
--
Tim Lamb