De-coupling Mat? What is there purpose please?

[The Famous Forry]

Is the decoupling mat laid on the top of the concrete base? Thanks

 

[Tile Marble Granite]

It can be installed on top of plywood or concrete no matter.

 

[The Famous Forry]

What is its purpose. Is it necessary? Thanks

 

[Tile Marble Granite]

It is used as a subfloor, it's anti crack and waterproof 100%. If your floor is timber, then it is highly recommended to install the Ditra matting membrane. If the floor is concrete you don't have to unless it's cracked.

 

[The Famous Forry]

It is used as a subfloor, it's anti crack and waterproof 100%. If your floor is timber, then it is highly recommended to install the Ditra matting membrane. If the floor is concrete you don't have to unless it's cracked.

Thank you for the advice detroitMi

 

[Hobnob]

A decoupling membrane is used to eliminate lateral movement.
I use a decoupler when tiling onto heated screeds to allow the tiles to move independently to the screed so as to avoid expansion cracks.
If tiling onto timber substrates I would use 6mm cement boards as they act as a decoupler but also enable a more suitable and sustainable substrate.