How to Screed a Floor

Screed unlocks a wide range of key benefits for concrete flooring projects. Not only does it fix any irregularities or imperfections within the concrete base, but it helps to improve load distribution, while keeping the project to a fast and efficient timeline.

As a result, it prepares an ideal surface for other flooring types, or achieves a smooth, flawless finish for a bare concrete floor. Thanks to these properties, screed is a highly popular choice in the construction and flooring sectors, amongst projects of all shapes and sizes. Have you heard about our low carbon concrete?

But, it’s important to note that, in order to achieve the best results for your project, you will need to select the right type of screed. Keep reading to find out more about different screed types, how to select the best fit for your specific project, and a detailed breakdown of the process of applying screed to a concrete floor.

How to choose the right screed

There are three main types of screed: unbounded, bounded and floating.

The key properties and main use cases of each type are as follows:

• Floating screed – this is poured on top of an insulating layer, and is not bonded to the underlying surface.
• Unbonded screed – this is poured on top of a damp-proof membrane, and is not bonded to the underlying surface.
• Bonded screed – this is poured on top of a concrete layer, and is bonded to the layer below. This is achieved using a bonding agent.

There are also other types of screed, which each offer their own specific benefits. These include insulating screed, structural screed and topping screed.

To find out more about other screed types, we have several related articles:

• Liquid Screed vs Traditional Floor Screed
• What is the correct mix for floor screed?
• Concrete Strengths & Grades
• Screed 5:1
• Screed 4:1
• Cemfloor Level Plus Liquid Screed

How to prepare your floor for screed

Preparing your floor for screed requires the following steps:

• Evaluate the floor, to spot any cracks or flaws that will need to be corrected.
• If there are any damages, patch them using a specialist compound or repair mortar.
• Completely clear the area, and ensure the floor is clean and clear of debris.
• Depending on the type of screed you are using, you may need to fix another layer on top of the concrete subfloor. This could be an insulating layer or a damp-proof membrane, for example.
• If you are not adding another layer, depending on the type of screed you are using, you may need to apply a bonding agent to the existing concrete floor.
• Conduct moisture testing, to gauge the moisture content of your existing floor. This will need to be within the levels required for your specific screed type.

This process is key to achieving a smooth, successful end result, and ensuring the long-term durability of your floor screed.

Creating the screed mixture

Typically, floor screed is a mixture of cement, water and aggregates. In most cases, the ratio for screed is 1 part cement + 0.5 parts water + 2.5 parts sand.

But, this ratio will vary, depending on the specific nature of the project.

For example, if the flooring is being installed in a domestic property, then the screed will need a much lower degree of strength. The screed will also need to be much finer, to achieve a higher aesthetic finish.

Comparatively, if the screed is being installed in an industrial warehouse, the strength of the screed will need to be prioritised, and the ratio adjusted accordingly.

How to apply concrete screed to your floor

The typical process of applying concrete screed to a floor is as follows:

1. Prepare the surface, following the steps outlined above.
2. Mix the screed, following the specific ratio that is required.
3. Apply the screed to the floor.
4. For traditional screed – pour the mixture onto the floor, then distribute it across the area, ensuring you create a flat surface as you do so.
5. For self-levelling screed – pour the mixture onto the floor, then allow it to spread across the area, and achieve a level finish.
6. Check that the screed has achieved a consistent thickness across the area.
7. Allow the screed to cure. Curing times will vary, depending on the screed type and ratio used. As it cures, the screed will need to be protected, and weight should not be applied to it.
8. Then, once the screed is fully dried, you can resume using the area, or prepare it for the addition of another flooring layer.

At iMix Concrete, we offer a dedicated floor screed installation service. We are proud to be one of the country’s leading concrete providers, trusted by countless domestic and commercial customers across London, Kent, Essex and surrounding areas.

Our floor screed specialists are fully qualified and have extensive experience in this field. Place your order or get a free quote today!

They will work with you to deliver an extremely durable, high quality concrete flooring, which boasts the best-fit solution for your specific property and its requirements.

To find out more about our floor screed installation service, contact our team.