What is liquid screed?

At One Guarantee we like to keep our finger on the pulse of new and popular building developments. In this article, join us as we focus on liquid screed and explore its finer details. Find out what it is, how it works and why should you use it in your next building development project.

What is liquid screed?

Liquid (or flow) screed has overtaken classic sand and cement screed to become a fairly standard flooring product.

It’s a thick liquid mix that’s applied by pouring or pumping from a mixing truck straight onto the area of (usually) concrete to be covered. It’s then dappled using a dappling bar to ensure it finds its level without leaving any air bubbles or faults. Some products are even self-levelling.

Once dried, the final flooring (lino, tiles, carpet, wood or laminate) can be laid on top.

What is it made of?

Usually screed is made of a sand and cement mixture. There are two main types of liquid screed: cement-based screed and a calcium sulphate mixture, or anhydrite screed.

It tends to be fine so it can pour easily and set smoothly. It’s possible to add other things either for decorative purposes (shingle, stone or coloured glass) or to make the screed stronger or more durable.

Why use liquid screed?

Liquid screed floors have gained popularity in tandem with underfloor heating. They’re also strong and durable. Liquid screed is a relatively easy and cost-effective way to create a quality floor surface that’s level and even. It easily fits any size, leaving it ready for laying the final flooring on top. It offers the benefit of low shrinkage and has minimal risk of cracking.

Where can it be used?

Almost anywhere indoors. Liquid screed can be found in domestic or commercial renovations or developments. It’s also good in environments subject to high temperatures.

In residential buildings, it’s particularly good if you’re laying new floors on top of existing ones. The liquid screed will fill any gaps or cracks and spread to the edge of the space.

It’s important to note that a screed floor left uncovered is not ideal for areas of extreme damp, such as wet rooms or bathrooms.

How long does it take for liquid screed to dry?

This varies hugely depending on the mix, conditions inside the building, ambient temperature, heating etc. It may be dry enough to take some light footfall in 24 to 48 hours. However, 7 days is the minimum before installing anything heavy or permanent.

Anhydrite screeds can sometimes be force-dried with the aid of underfloor heating. Cement-based will need a certain time before the heating is turned on. It’s imperative you know which type you have and leave it to dry according to the instructions.

What are the environmental benefits?

Liquid screed has great thermal conductivity and can help spread underfloor heating across the floor, making the build more energy efficient.

Easier to level, liquid screed can be thinner, meaning fewer resources used and, again, less energy is required during production.

Plus, with almost 40% recycled material used in liquid screed, it ticks another eco-friendly box.

Anhydrite screed also has a high gypsum content and produces less CO₂ than traditional sand and cement overall. So it’s a win-win ‘green floor’ situation for both consumer and producer.

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Sources:
www.designingbuildings.co.uk/wiki/Screed
www.ukscreedsltd.co.uk/liquid-screed-services/
www.easyflow.org.uk/liquid-floor-screeding/