What are the different types of floor screed?
There are several types of floor screed available and each has its own set of properties and benefits. The main types of floor screed are:
Traditional Sand and Cement Screed: This is the most commonly used type of screed, and it consists of a mixture of sand, cement and water. It requires a skilled team of workers to mix the sand and cement in the correct proportions, and then lay the screed manually using tools such as trowels and straight edges to achieve a level and even surface. The process also involves a significant amount of physical labour, including mixing and transporting the materials, spreading the screed, and smoothing it out. It has a number of drawbacks including inconsistent quality, it’s time consuming, greater risk of cracking, poor thermal conductivity.
Flowing Screed: Also known as liquid screed, can be broadly split into two categories, anhydrite liquid screeds and cement based liquid screeds. Both types, as their names suggest, are in liquid form, and are transported to site via mixer trucks. On site, the material is transferred to screed pumps and with the use of hoses is distributed to where it is needed. One of the key advantages of flowing screed is that it can be applied quickly and efficiently, creating a smooth and level surface without the need for extensive manual levelling. This makes it particularly popular for use on large projects such as commercial buildings, as well as in residential properties.
Self-levelling Screed: Also know as self-levelling compound, typically consists of a mixture of cement, sand, and additives such as polymers and flow agents, which give it its self-levelling properties. It is typically mixed with water to form a fluid consistency that can be poured onto the existing floor and will then self-level to create a smooth and even surface. Self-levelling compounds are generally bagged products which are mixed onsite, whereas liquid screeds are mixed at specialised batching plants.
The choice of floor screed will depend on various factors such as the purpose of the floor, the type of final flooring covering, the installation method and the time available for installation and drying. Liquid screeds are better suited when greater depths are required, for instance where minimum coverage is needed over underfloor heating systems. Self-levelling compounds on the other hand are perfect for thinner sections and when superior finishes are required for specific floor coverings.
