RESOURCES What is concrete screed, and why do you need it?

Home/Concrete/What is concrete screed, and why do you need it?

Concrete screed plays an important role in creating smooth, level floor surfaces. For both commercial and residential projects, it’s used to create a flat, even base to install other types of flooring materials. If you’re considering concrete screeding for your floor preparation, we’ll explain what it is, how it’s installed, and what it can do for your floors.

What is concrete screed?

Concrete screed is a substance similar to concrete but with smaller particles. It can be spread onto a concrete subfloor to even out the surface before other forms of flooring are installed. Commercial flooring materials such as carpet, tiles, stone, linoleum, and wood flooring can all be applied over concrete screed. 

What is the purpose of screeding concrete?

You need concrete screed to create a smooth surface for your flooring, ensuring that it lays perfectly flat on the ground. It can act as a conductor of underfoot heating, with the screed being laid on top. So, it acts as a kind of thermal or acoustic insulator. 

What are the different types of concrete screed?

Three main types of concrete screeding are commonly used in commercial buildings today. Your choice of screed will be guided by the intended use of the space, risks of moisture, and whether underfloor heating is being used. 

Bonded screed 

Bonded screed is so called because it is directly applied and bonded to the concrete base. Bonded screed is a wise choice for commercial spaces that must stand up to heavy loads or if there is not enough room for an unbonded screed. 

Unbonded screed

Unbonded screed lies over a damp-proof membrane with a thickness of at least 50mm. The unbonded nature of this screed means there is less chance of settlement and shrinkage risk.

Floating screed

Floating screed acts as an insulation material, most often with underfloor heating systems. The thickness of the screed varies according to the weight capacity of the floor. Calcium sulphate screeds allow for shallower depths, even for commercial purposes. 

How is concrete screed installed?

Installing concrete screeding in commercial spaces involves several steps. While the process may vary depending on the specific type of screed and project requirements, the general process followed by your installer will include the following:

  1. Surface preparation

The base or substrate is inspected to ensure it is clean, debris-free, and structurally sound. Any cracks, holes, or uneven surfaces are repaired. A bonding agent or a damp-proof membrane or insulation layer is installed, according to which type of screed is being used (bonded, unbonded, or floating). 

  1. Establishing levels and guidelines

Your installer will determine the desired screed thickness and finished floor level. They will set up guide or screed rails, ensuring they are level and aligned with the desired floor height. They will most likely use a laser level or other levelling tools for accuracy.

  1. Mixing the screed

Your installer will prepare the screed mix according to the manufacturer’s instructions or project specifications. The mix typically consists of cement, sand, water, and sometimes additives to improve workability or drying time.

  1. Pouring and spreading the screed

The next step in the installation is to pour the screed mix onto the prepared surface, working in sections manageable for the screeding process. Your installer will use a shovel or a rake to distribute the screed evenly within the guide rails.

  1. Screeding the surface

Your installer chooses a screeding method (hand screeding, power screeding, laser screeding, etc.) to level the screed to the desired height by moving the screed tool along the guide rails. Any voids or low spots will be filled, and excess material will be removed.

  1. Floating and finishing

After screeding, a bull float or power float is used to smooth the surface further and remove any imperfections. A finishing trowel may be used for a more polished surface if required.

  1. Curing the screed

The screed is cured properly to ensure optimal strength and durability. Your installer will follow the manufacturer’s recommendations or industry guidelines for curing time. During this stage, the screed surface must be kept moist and protected from rapid drying, extreme temperatures, or direct sunlight during curing.

  1. Inspecting and testing

Once the screed has cured, your installer will inspect the surface for any defects or irregularities. Necessary tests, such as moisture content or compressive strength testing, will be done to confirm the screed meets project specifications.

  1. Installing floor coverings

After the screed is fully cured and tested, your installer will add the final floor coverings, such as tiles, carpet, or other flooring materials, as per the project requirements.

For the most professional floors, choose Floorcon

At Floorcon, we are experts in commercial flooring preparation. We have the knowledge and experience to produce immaculate floors every time that enhance the value and visual appeal of your commercial space.

Contact us to revamp your flooring today.   

Related articles

Floorcon news & resources

Learn more about commercial flooring

New to the world of flooring products? Our news and resource page is full of valuable resources on the latest flooring products and installation trends. Dive in and learn something new today.

Project partners

Who we work with

As a commercial flooring company, we’ve collaborated with the building industry’s leading players to deliver outstanding results. Our seamless integration with other teams ensures some of the largest building projects in the state continue to stay on track and on budget.