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Substrate preparation for floor coverings includes sanding concrete and screed surfaces. This process is particularly gentle on the material and achieves very even results that require hardly any reworking. The following article shows how and why concrete or screed is sanded and what advantages sanding has over other methods.
How does grinding concrete and screed work?
A grinder for concrete and screed is equipped with a rotating grinding disc that is set in motion by a motor. Machines with a diamond coating are ideal, as they can grind down even hard concrete well.
When grinding, the device moves horizontally back and forth on the surface and cuts into the floor with a certain grain size to smooth it. Leveling distances of 1-2 millimeters are possible. For a perfect result, the grit size is doubled with each pass.
It is important that the sander is moved continuously over the floor and that a constant pressure is applied to achieve an even result. Crosswise movement is ideal. The resulting dust should be extracted immediately to prevent health hazards.
What is the purpose of sanding screed and concrete floors?
Sanding screed and concrete floors is an integral part of substrate preparation and serves both practical and aesthetic purposes. This often requires several sanding passes. If impregnating agents are applied to the concrete floor between these passes, sanding can replace sealing.
Sanding may also be necessary, for example, if the screed is too high and the doors can no longer be closed properly.
Even if the screed is to receive a new coat of paint, it is necessary to sand the surface beforehand. Sanding before plastering the floor is also recommended. The sanded, smooth surface means that the plaster layer no longer needs to be as thick, which saves both work and costs.
What are the advantages of grinding concrete and screed compared to other methods?
If only small amounts of material need to be removed, so that milling is not necessary, grinding concrete or screed is sufficient. It has several advantages over other methods: Among other things, grinding is much gentler on the material than milling, as the device does not penetrate as deeply into the concrete / screed. It is therefore not necessary to rebuild the concrete afterwards.
At the same time, grinding achieves very good adhesive tension values and high shear strength, and the surface appearance is also better compared to shot peening. Thanks to the large processing width of modern sanding machines, a large area output per hour can be achieved without creating unsightly blasting or milling paths.
Specialist company for concrete and screed work for over 25 years
Substrate preparation for floor coverings is one of the main tasks in our company for concrete and screed work. Our employees have extensive expertise and many years of experience and ensure that substrate preparation is carried out quickly and professionally so that your project can progress quickly. Simply make an appointment for a consultation and let us know how we can help you. We look forward to contributing to your new floor with our work.
Questions and answers about grinding
The aim of sanding is to give the screed an adhesive surface to which a floor covering (with adhesive) is to be fixed. A single-disc machine (e.g. with 16 grit) is usually used for this purpose, which removes loose material and roughens the surface. If, on the other hand, there are unevennesses in the screed, this must be sanded down - for example with a so-called diamond rotary disk. Grinding serves to smooth out unevenness and remove light impurities from the surface. In addition to safety aspects, aesthetic aspects are particularly important here.
It is only possible to grind a new concrete floor once it has completely dried out and set. Depending on the composition of the concrete, this can take up to 4 weeks. Old concrete floors can be sanded at any time, they should only be in a swept clean condition.
As it is the sole floor covering, exposed screed must always be sanded. Only by sanding can, for example, the patterns that are created when using different colored cements be optimally produced. Several work steps are often necessary to achieve an aesthetically pleasing surface: Milling is followed by sanding with different grit sizes, which are ideally doubled with each pass (example: pass 1: 160 grit, pass 2: 320 grit)
The costs are usually calculated per square meter and depend on the amount of work involved. If we can help you with your project, we will be happy to provide you with an individual quote after a personal consultation. Simply contact us by telephone or e-mail.