If, in an effort to get a perfectly level floor, would self leveling material be put down before the ditra is applied or after? PJB

Before.

Then what are you going to do? How about the subfloor, is it suitable for tile?

Jaz

Jaz, I have 3/4 particle T& G subfloor with 1/2 plywood screwed 4-6" square on top of that. The plywood is quik trac with pex tubing dados in it, hydronic radiant heat. The floor is pretty tight, 1 1/4" total thickness on 2x10 joists. I want to use ditra because of the temperature changes from the heat and because it is a great product. There are however some level issues that I may address with a self leveling float. It makes sense to put that down first, then the Ditra membrane. My only worry is the float -where it gets very thin and potentially not a great bond. PJB

PJB, looks like thems boys left ya hangin'
DITRAS always the last step in most all multi sandwithed floor senarios,i'd not recommend any self levelor over ditra,and dont believe i've seen it in any spec.
just prime the warm brd and staple the hell outta the lathe,allow for PLENTY of perimiter expansion,due to nature of the slu and the hydronic expansion/contraction. keep your pour to at least 1/2''minimum in high points of floor.
Adding crack iso over the slu'hot pocket is a wise choice and DITRA would be good or LATICRETES new 125 crack /sound control thiset if ya could get your paws on a bag, good luck