• The Difference Between Liquid Screed and Concrete Screed


    In the past, the screed market was dominated by the use of concrete and liquid screed. Screed installation was a time consuming and labour-intensitive task that many contractors dreaded.

    However, as we will discuss in this article, the development of the liquid screed industry has solved many of the problems that contractors used to face. But it’s not just beneficial for them. Liquid screed can be a quick and efficient solution to your flooring or construction projects. Let’s explore why:

    Concrete Screed

    Concrete screed is used to form a thin, top layer over a structural substrate such as concrete subfloors. It is traditionally made up of a  1:3 or 1:4.5 ratio of cement to sharp sand. Its purpose is to provide a flat and smooth surface so that finishing materials like carpet, tile or wood boards can be laid on top of.

    The screed is laid on the surface by manually mixing and shovelling the screed mix across the intended area. Then a screed bar is used to level out the screed. It takes a lot of effort to achieve a smooth and high-quality finish with this method. The problem with cement is that as the material dries, it starts to shrink. The amount of shrinkage can be hard to estimate and compensate for. From the thickness, ratio to the temperature and humidity, all of the above can adversely affect shrinkage rate.

    Liquid screed

    Liquid screed, also called self-levelling or flowing screed, is a calcium sulphate composition combined with water to produce gypsum or even anhydrite screed. Anhydrite screed refers to the mineral – anhydrous calcium sulphate – which is used, but its properties are similar to gypsum.

    Flowing screed is used for both commercial and domestic building projects to apply floor finishes. It can be either bonded directly to the surface substrate (i.e concrete) or remain unbonded using a membrane between the screed and the substrate. It’s often used in combination with under-floor heating systems for the reasons we will discuss below, but for the time being, all you need to know is that liquid screed can create incredibly level and durable surfaces for flooring.

    Benefits of liquid screed

    1. Speed: Liquid screed has a faster drying time than traditional concrete screed.  Typically, it takes only 24-48 hours for the screed to dry enough to walk on. The process itself is also much quicker than traditional screed and far less labour intensive. The reason is that once set up; the liquid screed is very quick to pour. A 25m2 area will only take around 20 minutes to cover from start to finish. This means you save costs on time and labour. In addition, this takes off a lot of the physical strain involved in the traditional screeding process from a health and safety perspective.
    2. Reduced Risk of cracking and shrinkage: One of the biggest setbacks when using concrete screed is the cracking introduced during the drying and shrinking process. In comparison, the calcium sulphate mix in liquid screed is far less prone to shrinking, which means less cracking. The material is also more malleable and spreads much easier, meaning that hidden cracks won’t show up later on down the line.
    3. Smoothness: As mentioned, it is pretty challenging to get a smooth surface with a traditional concrete screed. First, the surface has to be levelled with a wooden screed or leveller. Then a magnesium float compound is applied to remove excess moisture. This is followed by a concrete edger, concrete groover and more float. As you can see, it is quite a process and, even when applied, doesn’t necessarily guarantee a smooth surface. On the other hand, Liquid screed is said to be self-levelling because the liquidity of the mixture means it spreads itself evenly over the surface. This, as you can imagine, speeds up installation considerably and provides far better smoothness and evenness over the surface.
    4. Under-floor heating: One of the enormous advantages of liquid screed is its use for underfloor heating systems. Not only is the coverage better over any pipeworks, but the density of the liquid ensures that no bubbles or gaps are contained inside. These can slow down the transference of heat from the system to the room. As a result, the heating system will be far more effective for occupants. To this end, liquid screed can be applied with a thinner layer than traditional screed. This benefits heat efficiency but also contributes to a lower material cost.


    In summary, liquid screed is a far superior option for flooring in commercial and domestic buildings. As we covered, it is faster, more heat efficient and smoother than traditional screed options. Nevertheless, if you want the best flooring outcome from your project, you need an experienced contractor for the job. UK Screed LTD provides Liquid Screed, Underfloor Heating, Floor Sanding, and Pump Hire Specialists to cater to all your questions and screeding needs. So whether you need liquid screed in Bristol or flowing screed in Gloucestershire or anywhere within our 200-mile catchment radius, with 15years of experience in the industry, UK Screed LTD is here for you.

    Post Tagged with ,
Comments are closed.