Screed

Screed

A screed is a concrete layer with fine-grained aggregate, which we apply to the raw concrete layer for leveling. Depends on requirements, which the floor is to fulfill, The screed is made directly on the raw floor or on a layer made of heat and sound insulation material. The screed is the base for the floor covering, on it, tiles or carpet are laid. The screed must therefore be sufficiently smooth and even.
Screed, laid directly on the raw substrate is called a connecting screed. It is only used then, when heat and noise insulation is unnecessary, e.g. in a free-standing garage without a basement. The screed is often separated from the raw substrate (ceiling) with foil or tar paper and is then not permanently connected to it. The screed on top of the insulating layer is defined as a non-bonded screed. Screed layer (30-45 mm) must be self-supporting. The loose screed does not have a direct connection with the substrate and the wall; the insulating layer separates its entire surface from them. The insulating layer for non-subsoil-free loft consists of materials specially approved for this purpose, boards suitable only for thermal insulation must not be used. As an insulating material, synthetic materials such as polystyrene are used (PS) or polyethylene (ON), fiberglass or mineral mesh, cork crumbs and other insulating materials. The insulating material compresses under the weight of the screed, it therefore becomes thinner than previously assumed. Its final thickness should be taken into account when calculating the thickness of the layer. The size is indicated on the package, by which the insulation material is compressed, e.g. 35/25, which means, that the insulation material of the original thickness 35 mm after installation it compresses to 25 mm. In order to achieve a good effect, the insulating material should be laid seamlessly. We cover the layer of insulating material with oil paper or plastic foil, which we pull up above the screed surface by the wall. Before applying the screed concrete, a strip of insulating material with a thickness of 10 mm. After the screed has hardened, use a sharp knife to cut off the protruding edge of this strip.