What Is Floor Screed & How Is It Used In Underfloor Heating?

Person working on underfloor heating structure

If you’ve not heard of floor screed before then you’re certainly not the only one. At Pipelife Eco we often get asked what screed is, which is exactly why we’ve put together this quick guide explaining everything you need to know. Before we go into more detail on what floor screed is used for, let’s take a minute to define what exactly it is. 

What is floor screed?

Screed is a thin layer of mortar that provides a smooth, even surface for flooring to be laid on top of. Floor screed is usually made from fine grains of sand and is typically placed above a concrete base for the final layer of flooring to be placed on top. 

There are two main types of floor screed that are commonly used. These are: 

Semi-dry screed: Made from a mixture of sand and cement, semi-dry screed is mixed with water to create a smooth consistency before being applied with a flat-edged tool and levelling boards. This is the most traditional type of screed that is used. 

Liquid screed: Sometimes referred to as ‘self-leveling’ or ‘flowing’ screed, this type of floor screed creates a flat surface itself without the need for levelling boards or flat-edged instruments. Liquid screed isn’t prepared on site but instead is poured directly onto the concrete base. This allows it to be applied a lot more quickly than semi-dry screed and in addition to this, it is also fast drying. 

Why is floor screed important? 

As we’ve mentioned, floor screed is used to level out a concrete sub base in order to help the application of floor finishes. However, floor screed is also commonly installed alongside underfloor heating to cover and bury the pipes, creating an even surface but also helping the transportation of heat. 

What’s the best floor screed for underfloor heating?  

Semi-dry screed is most commonly used for screeding underfloor heating, however liquid screeds are often a better choice. Ultimately, determining the best option depends on the individual requirements of the project. Semi-dry screeds are usually better for smaller projects where tools can be used to smooth the surface manually. However, liquid screeds are faster to apply. They also dry more quickly and are less likely to crack, meaning the underfloor heating system can be used more swiftly. 

The importance of floor screed depth 

Aside from creating a level surface, floor screed plays an important role in conducting heat evenly and efficiently across the surface of the floor. That’s why it’s important to ensure that the floor screed is the right thickness to allow the heat from the underfloor heating system to conduct efficiently. The professional who is screeding your underfloor heating system will be able to advise you on the right screed to use for the project, taking into account these important considerations. 

For more information on the best screed to use for underfloor heating, or to learn more about installing underfloor heating in your home, please don’t hesitate to get in touch with our knowledgeable team who will be able to advise you on the options available. 

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