All that said my dyir s understanding.
Tile decoupling membrane.
Crack isolation membranes are different altogether.
Schluter ditra membranes provide uncoupling through free space which allows for in plane movement that effectively neutralizes the differential movement stresses between the substrate and.
The membrane must overlap the joint by at least 50mm.
Coupling membranes are similar to crack isolation membranes but they re not the same thing.
These products must be load bearing and bonded to the substrate in order to function properly.
Some decoupling membranes like the ones that tile fix direct stock can be also used with electric underfloor heating systems.
I used the same tile s but did not use ditra on my basement floors.
The uncoupling membrane helps to prevent stress cracks from transferring through to the finished tiled surface.
So this means that they will have their own tests.
So they want all floor prep and leveling along with heat systems to be done first and the uncoupling membrane directly under the tile.
Schluter ditra or at this point any other uncoupling membrane do not fall under the category of crack isolation membranes as defined by ansi a118 12.
The powers that be in the tile industry want uncoupling membranes to be their own classification separate from the cis membranes.
Tile has been successfully installed for thousands of years by incorporating an uncoupling layer or forgiving shear interface within the tile assembly.
Uncoupling membranes seem like they would prevent cracks also.
Waterproof decoupling membranes are designed to neutralise tensions between the substrate and the tiles.
Spread a thin layer of weberset spf across the joints and then bed a flexible layer of membrane into the adhesive.
That process was thin set directly on the cement floor back butter tiles and then grout.
Decoupling membranes are often used in newly built dwellings as the foundation structure moves slightly as it settles into the ground the membrane acts as a decoupling layer to absorb the lateral movements and so prevent the tiled floor from cracking and breaking up.
Crack isolation membranes are stretchy membranes designed to prevent cracks that originate in the substrate from causing the porcelain or ceramic tile above to crack.
Because they re stretchy crack isolation membranes dissipate the crack s force into the material preventing it from moving upward.
If the membrane is also to be used as a waterproofing layer the joints between sheets perimeter joints and movement joints need to be sealed.