Cement screed
Cement screed (CT)
Whether indoors or outdoors - cement screed (CT) is suitable for almost any area of application thanks to its many positive properties. The extremely strong concrete consists of a 3:1 mixture of sand and cement with a grain size of up to 8 millimetres. The cement serves as a binding agent and allows the screed to be applied directly to the floor, but also to other load-bearing substrates.
Cement screed has special drying properties: Rapid initial hardening allows it to be walked on after just 2-3 days. After around 10 days, the screed can be subjected to heavier loads. However, drying then slows down until it is ready for covering after around 30 days. Only then can further floor coverings be applied if required.
Areas of application for cement screed
Cement screed can be used as a subfloor in indoor and outdoor areas and is also suitable for areas subject to heavy traffic. Cement screed can level out unevenness or height differences in living spaces as well as in basements or on balconies, making it the ideal substrate for tiles or parquet flooring. Cement screed also cuts a fine figure on its own, as it can be produced without joints, which creates a great visual effect. To make the surface particularly smooth, the cement screed can be sanded and sealed.
Tip: A so-called hard aggregate screed is suitable for areas subject to particularly high loads. With this type of screed, the aggregate of the cement screed is comparatively large. This increases the surface abrasion resistance, making the screed even more durable.
Laying techniques and types of cement screed
Cement screed can be applied in dry form ("dry screed") or in viscous form ("flowing screed"). The latter has the advantage that it is self-levelling thanks to its soft consistency.
Cement screed can be bonded to the substrate in different ways, resulting in different types of screed. These each have specific properties and are suitable for different areas of application. The various installation techniques for cement screed are briefly described below:
- Bonded screed: Here, the screed is firmly bonded to the supporting concrete (bare floor) to stabilize it. As it does not have to have any load-bearing capacity itself, a screed thickness of 25-30 millimetres is usually sufficient. Composite screed is often used over the entire surface, but it has no heat or sound insulating effect. Typical areas of application are commercial and commercial premises, basements and garages.
- Cement screed on a separating layer ("floating screed"): Here, the cement screed is laid on a thin intermediate layer, which serves as a separating layer to smooth out temperature fluctuations and protect against moisture rising from below. However, the screed, which is at least 35 millimetres thick, does not have a sound or heat-insulating function. This laying technique is well suited for basements and other subterranean rooms, but also for outdoor areas such as balconies or terraces.
- Cement screed on an insulating layer ("floating screed"): For good sound and heat insulation, an additional insulating layer is required, on which the cement screed is laid floating, i.e. without fixing to any side. How thick the screed layer should be depends on the hardness of the screed, but also on the thickness of the insulating layer and the traffic load of the floor.
- Heated screed: This screed is laid on the insulation layer above or below the underfloor heating and is specially heated during the drying phase. Caution: The average temperature of the heating must not exceed a certain value. Particularly good heat distribution can be achieved by embedding the heating elements in the cement screed. If the heating screed is laid over a pipe, it must be at least 45 millimeters thick.
What to look out for when laying cement screed
To achieve a perfect result, the following must be observed when laying cement screed:
- After application, the screed must be protected from direct sunlight and draughts for at least 7 days so that it can develop its full stability.
- To prevent the screed from drying out too quickly, it can be covered with special plastic sheeting.
- For outdoor use, the screed can be protected from extreme temperatures or temperature fluctuations during drying with heat protection mats or foils. A constant temperature of at least 5°C is recommended.
The advantages of cement screed at a glance
- Fast initial hardening
- Particularly strong and robust
- Extremely resistant to water
- Tolerates high temperature fluctuations when cured
- Very high wear resistance
- can be produced without joints
Arrange a consultation now
Would you like to find out more about cement screed or get professional advice on which screed is best suited to your needs? Then we are exactly the right contact for you. We will be happy to assist you with our expertise and over 25 years of experience. We will provide you with professional and reliable support from the initial consultation to the completion of the screed work you need. We look forward to hearing from you!
Questions and answers about cement screed
Cement screed is particularly resistant to moisture, making it very suitable for use in wet areas. It is only important that the screed is completely hardened beforehand.
It can take 20-30 days for the cement screed to dry completely. In this case, completely dry means that the moisture content of the screed is less than 2%. Only then can further floor coverings be laid on top.
The cement screed should be between 4.5 cm and 8 cm thick, depending on the area of application and the laying or bonding technique.