I disagree completely!
Wait...what was the question?
Oh...never mind. I'm still suffering the trauma of the Red Sox returning Julio Lugo to the lineup for last night's game against Cleveland.
Ditra can indeed go over the heating mats. No worries.
With your guy having attended Schluter Shkool, he sounds conscientious. But I'll throw the following out anyway:
The only other thing I'll add regarding your installation is that code requires that a shower pan hold 2" of water depth should the drain become plugged. We normally refer to this as you need 2" of elevation between the top of the curb and the top of the drain.
Now the curb can be a traditional one, like a raised one at the shower door. Or the curb can be a gradual roll-over hump that I've done fr ADA bathrooms. Or the curb can be non-traditional like yours, and the 2" of drop can be made up of sloping floor.
Regardless, if you plug the shower drain and fill the shower so that you have 2" of standing water depth at the drain, water should not be able to leak out of the bathroom. Anywhere in the bathroom.
As an aside, to make your Ditra floor waterproof, a strip of Kerdi should be run over the seams in the Ditra. To seal the Kerdi/Ditra joint on the floor at the shower door, the shower floor Kerdi should overlap the bathroom floor Ditra by a couple of inches.
To seal the floor-meets-wall areas, I've taken a 5" wide strip of Kerdi, creased it lengthwise and run 2-1/2" of it on the floor and the other 2-1/2" of it up the wall, behind the baseboard.
Don't forget the toilet, the flange will need to be sealed.
These tidbits may or may not be applicable to you. Your installer might have already addressed them. But I'm in a blabby mood today so I typed too much.
Q
