Sub-Floor Screeds

Explore our FAQs relating to Flowcrete's sub-floor screeds range. 

At what thickness should a screed be applied?

This depends on a number of factors such as the screed type, how it is installed and the load requirements of the floor. Other factors such as whether there is insulation within the flooring, or if underfloor heating is present also need to be considered.

With this depending on a number of factors, speaking to flooring experts is the sure way to find the ideal screed type for an installation.

When is a screed necessary?

Screeds are often used on uneven substrates as a way to help level out the surface in preparation for the final flooring layer. As well as being this levelling layer, screed also aids the bond between the substrate and the floor finish.

It is required when a colourful or functional floor is needed rather than a bare concrete surface.

How long does the screed take to dry?

A screed is normally regarded as being dry when it reaches a moisture level of 75% RH at which point it is suitable for the installation of moisture sensitive floor finishes, such as vinyls.

Traditional sand & cement screed dry at a rate of approximately one day per mm of the screeds thickness given good drying conditions.

Isocrete screeds are quick drying screeds designed to dry at a much faster rate than traditional screeds & the Flowcrete Technical department can advise on the most suitable screed type for use in different applications.

Are joints required in screeds?

Screeds are rigid materials and are not designed to bridge across structural movement joints.

However, additional factors will also influence the need for joints in the screed. These could include the layout of the building and the possible need for shrinkage control joints or the presence of underfloor heating circuits in the screed etc.

Can screeds be used outside?

Most screeds are used for internal purposes, often covering heating systems, acoustic or thermal insulation. Polymer-modified screeds can be installed in external locations as they are hard-wearing, water resistant and able to withstand a more rigorous environment.

Will the screed shrink?

All screeds will shrink as the moisture leaves the system. Stress control joints can be put into the screed to control this and prevent random cracking during the shrinkage stage. These joints can be filled once the screed has dried.