Next in our series of Ultimate Guides is our guide to screed. A crucial part of many construction projects, screed is a thin concrete layer that is used to cover a concrete floor or underfloor heating system.
Once the screed layer is in place, either the final decorative floor covering can be installed on top of it, or the screed itself can be used as the final floor finish.
There are five main types of screed that we use here at EasyMix, each one providing their own strengths and unique characteristics. Depending on what you require screed for, certain types will be preferable over others.
This mix is fully bonded to the substrate - the underlying layer- using a bonding agent. With a thickness ranging from 25-40mm, it is typically used for surfaces that will experience heavy loads, such as driveways or car parks, but it can also be used when cast-in water pipes are being used in underfloor heating system.
Floating screed is installed at a depth of approximately 35mm, usually in places where underfloor heating is present or that thermal or acoustic insulation needs to be used. It typically has a thickness of 65mm-75mm, and its main purpose is to increase the heating efficiency of a building.
A very popular screed, also known as self-compacting or calcium sulphate screed, it sets in 24-48 hours, which is the main factor in its widespread usage. It can be installed as a ‘bonded’ or ‘floating’ screed, with thicknesses of 30mm and 40mm respectively, depending on how it is installed.
This type of screed is laid on top of a damp-proof membrane which sits between the screed and the concrete base. Thanks to the membrane, the likelihood of shrinkage, settlement and damp occurring is significantly reduced. It is available in two mixes: a sand/cement mix, which has a thickness of 50mm, and a calcium sulphate mix, which is 30mm thick.
Screed is generally used in conjunction with underfloor heating, but this type of screed is different in that it is laid directly on top of the heating system, rather than over a layer of insulation above it. As there’s no insulation layer, the heating system does not suffer from cold spots, which means the output is more consistent. The screed can have a thickness from anywhere between 65mm and 75mm for sand or cement mixes, to 50mm for a strengthened or anhydrite mix. If a calcium sulphate mix is being used, a thickness of 20mm is required.
If you’re undertaking a project that involves the installation of a floor, and if that floor is going to incorporate underfloor heating, then you’ll need to use screed. It functions as an excellent conductor of heat, and it also helps prepare the floor for the final finish. In some environments, where preserving the aesthetic of the floor is not a priority, screed is often used as the finish in itself.
If you have any further questions about screed, we’ve created an FAQs page on our site that answer some of the most common queries about what it is, how it might be used and other helpful information regarding its proper usage. Read our FAQs page
If you’re in need of screed for your project, get in touch with EasyMix today. We supply a range of screeds in any quantity you may need.
Before you contact us, it can help to work out how much screed you might require - for this reason, we’ve created a screed calculator - use this to work out your required quantity of screed, contact our friendly team and we can arrange delivery.
EasyMix Concrete are London’s most reliable supplier of concrete services, screeds and aggregates. For more information about the work we do, please contact us today and we’ll be more than happy to help.
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