Its primary function is to help neutralize stresses in movement between the substrate in my case the subfloor but it can also work with osb or plywood and the tile.
Ditra mat on concrete slab.
We recommend using schluter ditra heat duo uncoupling membrane.
Ditra is 1 8 3 mm thick which minimizes tile assembly thickness and reduces transitions to lower surface coverings e g carpet engineered wood and vinyl.
Ditra is essentially a molded plastic sheet with fleece backing.
Again i think this is a bad idea.
A seasoned floor that never sees moisture you could skip the ditra.
Megabond from lowes or kerabond are good un modified thin sets.
The schluter ditra uncoupling membrane is specifically designed to allow the installation of ceramic and stone tile over any even and load bearing substrate.
Don t install tile the same day over the ditra heat mat schluter says this is ok.
Ditra heat tb has additional insulation for going over concrete floors.
This will reduce heat loss to the concrete substrate and improve the floor warming response time.
Un modified under and over the ditra.