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Why Use A Liquid Screed?

Liquid Flowing Benefits & Highlights

Our Liquid Flowing screed can be used in almost any application of either new build or property renovation projects, and especially excells in rooms that are not a traditional shape as it can flow to whatever shape floor you wish. It’s suitable for both commercial and residential applications – It’s been installed in almost all types of building including hotels, schools, hospitals, shops, airports and hotels etc.

Due to the high recycled and gypsum content, liquid screed is very kind to the planet as the amount of CO2 used throughout the process is far less than traditional sand and cement techniques.

Using liquid floor screed is growing in popularity to the point that it is now the leading floor installation method in most western European counties. At Pure Screed we can be involved in as much of the process as you like – From the preparation, through to installing underfloor heating, and laying the final liquid screed. Please click on the links to the left of the page to learn more about the benefits of using Pure Screed:

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Liquid Screed Floors & Under Floor Heating

Almost all types of screeds and concretes can work with under floor heating installations, however the under floor heating will give very different results depending on the type of screed floor which has been used, and the depth of the screed or concrete.

As a general rule, the thicker the screed or conrete floor being used, the longer the delay in both warming up and and cooling down of the under floor heating. Both under-heating and over-heating can result from getting this calculation wrong, so it’s important that the correct amount, and correct type of screed is used.

At Pure Screed, we would generally recommend a Liquid Flowing Screed for under floor heating as all the evidence suggests that the heat output is optimised in every way: Everything from the flexible installtion options to the warm up and cool down time.

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Liquid Screed Thermal Conductivity

Our liquid screed has approximately twice the thermal conductivity, compared to traditional thicker screed. This simply means that the under floor heating system which sits within the screed requires less energy to run and can reduce your associated bills by approximately 10%.

Environmental Impact Of Liquid Screeds

Using a liquid floor screed is one of the best ways to reduce the amount of carbon dioxide involved in your installation. Up to 36% of the product is made from recycled material, and gypsum content makes it exceptionally kind to the planet as the amount of CO2 produced is far less than traditional sand and cement.

Get A Perfect Finish Every Time

The industry standard tolerance for a liquid screed floor is “SR2 +/- 5mm” under a 2 meter level. However, compare this with a traditional (non liquid) floor screed, and you’ll see that this is generally installed to an SR3 tolerance which is +/- 10mm under a 2 meter level.

Essentially this means that the flatter the finished floor is, the easier it is to lay floor finishes such as wood and carpet. Liquid screed is far superior in this respect.

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When Is The Right Time To Install My Floor Covering?

Pure Screed offer a humidity and RH testing service to confirm when the floor is correclty dry so that our customers know when the time is right to lay or install the relevant final floor coverings.

As you can see in the diagram below, the thermal conductive difference between sand and cement vs liquid screed is clear – The difference shown in consitent and high temperatues is just 80 minutes after installion:

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Preparation Advice & Options

Before any type of screed is installed into your property, an amount of preparation is required to ensure a perfect finish. The preparation needed will vary from property to property, but as a rule of thumb, the following will be required in this approximate order from the ground up:

  1. A Damp Proof Membrane (DPM)
  2. Slab
  3. Insulation
  4. Vapour Barrier
  5. Finally followed by the Floor Screed of your choice

If underfloor heating is also needed, a very similar amount of surface preparation will be required, in the approximate following order:

  1. A Damp Proof Membrane (DPM)
  2. Slab
  3. Insulation
  4. Vapour Barrier
  5. Underfloor Heating Loops
  6. Floor Screed

Depending on your property, Pure Screed can also complete the preparation and installation on upper floors (using either a concrete plank or a beam and block construction). On upper floors within a property, you will generally not need to install a ‘Damp Proof Membrane’, however the ‘Vapour Barrier’ is usually still required. (This is because the vapour barrier is required by the insulation manufacturers, to prevent contamination from the screed).

The Vapour Barrier actually forms a separation layer to minimise cracking should any movement occur below the screed after installation for any reason. With this in mind, you’ll need to ensure that the Vapour Barrier is perfectly smooth to stop the fresh screed from cracking. Finally, a ‘Perimeter Strip’ or some sort of edge insulation should be placed around all edges to separate the screed from the walls and protect everything during the installation.

Installation Methods

The liquid screed will be delivered in a large mixer truck and Pure Screed installation engineers will use a pump to lay the product at an installation rate of approximately 5 minutes per meters cubed. The finished surface will then be dappled with a T-bar tool to remove any air bubbles and produce a smooth surface for the final finish.

Until the screed has fully hardened, you’ll need to ensure the surface is protected from direct sunlight, water, and severe draughts. After three days it is recommended that doors and windows are opened to assist with drying and the further release of moisture.

Installation Speed & Drying Time

As an examples, a 4-man-team could install approximately 1000-2000 meters cubed of liquid screed per day, compared to perhaps 150 meters cubed of traditional screed.

On top of this, you can safely walk on a new liquid screed floor within approximately 24 to 48 hours compared to approximately one week for traditional sand or cement screed.

At Pure Screed our installations will dry at a rate of approximately 1mm per day up to a screed depth of around 40 mm if the drying conditions are correct.

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Liquid Screed Depth Options

Our Liquid Floor Screed can be laid at shallower depths than traditional screed which has a whole range of advantages:

  1. Less height can result in the liquid screed being a more cost effective alternative than sand and cement due to the fact that less product is required.
  2. The reduction in depth usually means that the screed is ready for final floor finishes in much less time than a traditional screed.
  3. Lower depths of screed will make our Under Floor Heating system more responsive during both heating-up and cooling-down cycles as they have less screed surrouding them.
Liquid Screed Strength

At Pure Screed, our liquid screed can achieve an in industry standard strength of “C30 N/mm squared”. We are also able to supply and install ‘extra strength screed floors’ that can achieve “C35 through to C40 N/mm squared” – Please contact us today for further details if you have a specific strength requirement for your project.

Liquid Screed Health & Safety

Our liquid screed is protein free and will not harbour any bacteria after installation.

Liquid Screed Sound Properties

During the industry standard ‘BRE Screed Test’, our liquid screed adhered to soundness category A according to BS 8204: Part 1.

Liquid Screed Fire Risk

Our liquid screed floor surfaces are non-combustible and have been tested to the industry standard ZB5476 (Part 4).

Screed Quality Control

Once we arrive on site at your project, the liquid screed to be used is pre-mixed, with the viscosity being checked prior to installation. This is to ensure it’s consistent throughout, and in line with the manufacturers installation guidelines.

In comparison, traditional sand and cement screed is inherently difficult to put robust quality control measures in place with as there can be wide variations during installation.