What is a Screed?
A screed is a construction element laid in a range of thicknesses, and its purpose is to bring the installation surface for the flooring to the design height and to provide a surface suitable for installing the specified flooring. Screeds are usually made from pre-blended mortar mixed with cementitious binders or anhydrite-based binders. Depending on whether it is laid directly on a supporting structure (for example a reinforced concrete floor slab), on an isolating layer (for example a vapour barrier) or on a layer of thermal insulation and/or soundproofing material, it is known as a “bonded”, “unbonded” or “floating” screed. A screed may also have an underfloor heating/cooling system incorporated within its structure and, in such cases, is known as a “heated” screed. When a screed is laid, it must mainly guarantee the following:
- that it forms a substrate suitable for installing the specified flooring;
- that it is laid on schedule;
- that its durability under various service conditions (laid internally or externally, for civil, commercial or industrial flooring, etc.) is not compromised.
The durability of flooring, therefore, is influenced by the characteristics of its substrate, which means the type of product selected to make the substrate, the quality of preparation work, how it is laid and the compactness and curing of the mix. To sum up, when choosing which product to use to make the screed, be it a special binder, a pre-blended mortar or traditional site-prepared mortar, you must take into consideration the final use of the screed, site
conditions (internal or external, the thickness to be laid, etc.), the type of flooring to be installed, the time to wait before installing the flooring and the time required before putting the flooring into service.
What is self leveling compound?
Self-leveling compound is polymer-modified cement that has high flow characteristics and, in contrast to traditional concrete, does not require the addition of excessive amounts of water for placement. Self-leveling concrete is typically used to create a flat and smooth surface with a compressive strength similar to or higher than that of traditional concrete prior to installing interior floor coverings. Self-leveling concrete has increased in popularity as the degree of flatness and smoothness required for floor covering products has increased, with vinyl goods becoming thinner and floor tiles becoming larger, for example.