An uncoupling membrane, also called anti-crack matting, is a thin layer laid between the floor and your tiles. It's always worth using if you're tiling over:
- timber floorboards or plywood
- new screed that may still be drying
- floors with small cracks
- underfloor heating
Floors naturally move slightly over time as they expand, contract and dry out. The membrane absorbs this movement so it isn't passed up to your tiles, reducing the chance of them cracking.