The untrained eye may not be able both to identify and understand the difference between concrete and floor screeds. Even though both materials are made from the same basic ingredients, cement, aggregates, and water. Concrete and floor screed are both formed by mixing cement with water, forming a paste that coats the sand or aggregate surface and hardens by a process called hydration. However, the size and grade of aggregates used, as well as the consistency and finish of the mix, differ in the two materials due to their very different intended uses. Compared to screed, concrete contains larger, harder aggregates. These are the key elements that give concrete its strength and durability. In the construction industry, concrete is used for structural purposes such as floor slabs due to its high strength potential. Concrete is the most commonly used man-made material in the world. Concrete, on the other hand, is a rougher mix that contains significantly more aggregates than screed.
As a finishing layer, screed is generally applied on top of concrete slabs and is used as a finishing layer on internal floors or to level the surface prior to final floor coverings such as carpet, tiles, natural stone, linoleum, wood flooring, and resin coatings. A colourful or functional floor is preferred to bare concrete surfaces when a colourful or functional floor is required. In industrial or commercial settings, where traffic will be frequent, a more robust screed is required than in DIY or residential applications. In most cases, screeds are used only for internal purposes, such as to cover heating systems, acoustic or thermal insulation. Screeds modified with polymers can be installed in exterior locations because they are hard wearing, water-resistant and able to withstand harsh environments.
Traditionally, screeds are sand and cement mixtures, blended on site and applied. The factors described above, however, are unpredictable because the properties and ratios can’t be precisely predicted, creating a weak flooring layer prone to cracking, peeling, or collapsing without warning. The market offers a number of screeds and kits that offer enhanced strength and a faster application speed.