Floor ScreedersFloor Screeders
Floor screeders are used to mix, spread or pump out a pre-mixed floor topping in an efficient and effective manner. They can be either traditional cement sand, free flowing or pumpable self-smoothing screeds. It is important to specify the correct depth and type of floor screed to achieve a successful flooring finish. It is also necessary to correctly specify construction tolerances and provide falls if a structural floor is to be constructed beneath the screed.
Levelling or self-smoothing screeds (traditionally a 1:3 or 1:4.5 ratio of Portland cement to sharp sand) are designed to give a defined layer in which the final floor finishes can be installed, such as tiles, wood, linoleum etc. They do not contribute to the structural performance of the floor.
Essential Guide: Understanding Floor Screeders and Their Role
Wearing screeds are typically more costly than levelling screeds and are designed to contribute to the overall structural integrity of the floor. It is recommended that they should be a minimum of 25mm, although BS 8204 Part 2 recommends a depth of 30mm for bonded and unbonded floors.
Pumpable flowing screeds (also known as liquid or pumped self-smoothing screeds) are becoming more common and are usually anhydrite-based compounds with a calcium sulphate binder. They are poured from a hose and can be laid in as little as an hour. They can be applied up to a thickness of 35mm for underfloor heating systems and are capable of achieving a very high standard of smooth finish (similar to that of a traditional sand/cement screed) with a tolerance of 10mm variation over two metres.
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