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What is Anhydrite Screed? Complete Guide!

What is Anhydrite Screed?

Anhydrite screed is also known as calcium sulphate screed. As evident from its name, it consists of an anhydrite binder, along with water, sand, and other additives, i.e. polymers and catalysts. An anhydrite screed is a sustainable option as it consists of an anhydrite binder.

Anhydrite can be obtained either from natural mineral deposits or as a by-product of other industrial processes. Instead of disposing of it in landfills, it is milled and is then ultimately used in screed formation hence making it an eco-friendly option. In the UK, it is mainly sourced from the chemical industry.

Anhydrite screed has been introduced lately in the UK construction industry i.e. around 35 years ago. It comprises 20% of the screed market and is becoming increasingly popular. It is extremely durable with immense benefits. Continue reading to explore its benefits.

Applications of Anhydrite Screeds

Anhydrite screeds are used majorly in four flooring screed constructions, as explained below:

  1. Wet underfloor heating: In this type of flooring screed construction, the screed and floor base are separated by a layer of any insulation material. Then, the underfloor heating pipes are installed above it.
  2. Floating: In this type, a rigid layer of thermal or acoustic insulation material separates the screed and floor base
  3. Un-bonded: For this construction type, a damp-proof membrane (DPM) separates the screed and floor base.
  4. Bonded: In this type of construction, the screed layer is laid directly onto the floor base, with just a bonding agent between them.

Benefits of Using Anhydrite Screed


It is in liquid form which means it can be pumped using concrete pumps and other equipment instead of laying it by hand. It has self-levelling characteristics that further make it an easy option. 


It offers immense strength and durability that makes it a perfect candidate for high-traffic and heavy load-bearing areas. It is widely used in residential and commercial projects. It is perfectly suitable for projects with an estimated longevity of 50 to even 100 years!


Anhydrite screed is a more sustainable option than traditional screeding options as it is made of recycled products, i.e., 36% of its composition. Moreover, unlike traditional screeds, it also results in lesser CO2 production.

Less Shrinkage

It causes way less shrinkage, unlike cement-based screed, so it can be laid in a larger base without the fear of shrinkage cracks.

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Increased Density

Anhydrite screed has great thickness and density. That’s why it holds the characteristic of offering sound insulation.

Thermal Conductivity

One of the important characteristics of anhydrite screed is its thermal conductivity. Contrary to traditional screed, it has a high thermal conductivity rating, allowing heat to pass through it. That’s why they are often laid on underfloor heating systems.

Fast Drying

It can dry within a week as compared to traditional screed which may take up to 4 weeks to dry. This way using it ensures timely project completion and lesser inconvenience. Moreover, under monitored conditions, it takes one to two days for the screed setting to allow light foot traffic.

Light Weight

It can be applied in a thin layer making it a lightweight option than traditional screed. Furthermore, it doesn’t require as much reinforcement as traditional screeds, making it a time and budget-friendly option.


Unlike cement screed, the anhydrite screed doesn’t curl over the edges.


How Far Can Anhydrite Screed Be Pumped?

Anhydrite screed pumping offers immense flexibility as it can be pumped 200 metres. It means it can be delivered 200 metres away from the point where the pump mixer is set.

Generally, a machine can pump approximately 20 cubic metres of screed per hour.  It implies that the pumping is so efficient that you can actually lay 360 m2 of screed within an hour!

If you are starting your construction project and need ready-mix concrete or want to hire a concrete pump, then contact the experts at Ready Mix Concrete.

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