Floor screeding is a key stage in the construction of any new building. It ensures the concrete base is level and allows floor coverings to be laid later on in the project. There are different types of floor screed available including unbonded, bonded and self-leveling. It is important to make sure the correct type of floor screed is specified for each building project and that it meets architecturally specified requirements for construction tolerances, surface finishes and structural action with the concrete flooring below.

It is also essential to ensure the area to be floor screeded is correctly prepared. The concrete should be clean, dry and free from dust. The area should then be covered using polythene sheets, or another form of membrane to keep the concrete flooring separate from the screed. These should overlap by 20-30cm and be taped together. The sheets should also go up the walls of the room by around 10cm. This prevents any leakage from the screed layer into the concrete subfloor as it dries and prevents any damage to the wall during this process.

All About Floor Screeding: Techniques, Materials, and Benefits

Some manufacturers produce pumpable flowing screeds that are suitable for a range of finishing materials, such as anhydrite or calcium sulphate compounds. These are quicker to lay than traditional sand and cement screeds and can be laid to a minimum thickness of 25mm for bonded and 30mm for unbonded finishes.

Once the floor screed is laid, it needs to be cured. This is a process that takes seven days and involves placing the floor under a polyethylene sheet with the edges sealed. This helps the floor to avoid shrinkage, and it is particularly important for areas where underfloor heating will be used. Once the curing period has been completed, the floor should be bull floated and any flaws or bubbles should be removed before installing the final finish.