Mixing ratio for cement screed

Cement screed is usually mixed on site, in a concrete mixer. Finishing screed from the hardware store should only be used for small repairs, but not for entire floor surfaces, not even in smaller rooms. At the end, the result here is usually much less good than with locally mixed screed made of cement and screed sand.

The "classic" mix

Grain sizes of 0-8 millimeters are generally used for screed sand for the standard cement screed or 0-4 millimeter grades for the sand grades; the different grain sizes shift the mixing ratio slightly upwards or downwards. For thicker screeds, from about 50 millimeters nominal thickness, however, gravel with a grain size of 0-16 millimeters is generally used.

By default, however, cement and screed sand come together in a ratio of 1: 4 during the mixing process, and the amount of so-called adding water can often vary depending on the materials used and the ambient conditions. As a rule, cement screed should be earth-moist for processing, but not liquid.

Additives change the mixing ratio

With different additives, the properties of the cement screed can be changed - for example, there are so-called "retarders" that can extend the processing time of cement screeds. This makes sense, in particular, where finished screed can be delivered from a factory and then processed in individual rooms. By appropriate additives can be made of the classical cement screed and a cementitious screed, the mixing ratios are then correspondingly different depending on the additive used and must be made exactly according to the manufacturer, otherwise the screed "bloom" and can collapse. For the mixture also a professional concrete mixer, better still a screed machine with additional promotion should be used, which then also facilitates the installation of the cement floating screed substantially. Cement floor screed also has consistently different properties than classic cement screed.

Video Board: PLASTERING(HOW TO LAY A FLOOR)sand+cement screed