Alum, a patch capable of spreading cement-based material. PVC, rubber floor coverings, carpets and parquet floor coverings, such as resilient applications need a very smooth surface. This surface should be used necessarily in alum. If not in use on the ground that all artefacts, will be reflected on the surface of the coating material of disorders, which makes it look bad on both the material and the material may shorten its lifetime. It is important to use because it will be used on the screed flooring material no matter how much quality, lower surface must be smooth and absolutely necessarily the be all this. It is highly recommended to use alum. This is necessary to make your application experts.