Tanking Floors
Waterproof floor tanking membrane systems differ slightly from tanking walls due to the nature of the subtrates. Chipboard wood floors are not suitable for tiling directly they require over boarding or replacing with ply wood before fixing uncoupling mat then tiles.
Uncoupling mat or decoupling membrane prevents expansion / contraction movement in wood floors being transferred to tiles so prevent cracks. This only works on movement across the surface of the floor it does not apply to vertical deflection (up and down movement) floors must be solidly fixed before you begin. Separation layers such as Dura-wp and Dura-ci can be used over ply wood flooring and act as an uncoupling mat and a waterproof floor tanking membrane.
Waterproof floor tanking membranes are not essential over concrete floors as these (unless Bison beam upper floors) are generally ground floors where water ingress to other rooms is less likely. Although a tanking membrane is not essential new floors, new screeds and floors with wet under floor heating (in screed heating) will benefit from an uncoupling membrane. As new floors and screeds dry out they move considerably as do heated screeds during the heating and cooling process. In these cases an uncoupling membrane will again serve to prevent tiles cracking and are recommended.
Further details on the how's and why's of waterproof floor tanking systems are covered in the How to section on tanking
