CONCRETE TRADITIONAL SUBBASES WITH SAND AND CEMENT
Traditional cement screed is generally composed of three materials used in appropriate proportions: cement, inert (sand and / or gravel, for example) and water. Various elements dosage depends according to external environment and the lease it will have (internal or external, for civil or industrial purposes).
Target is to level the surface, making it perfectly flat to share the load of the overlapping elements and receive the final flooring once the screed is fully matured.
Its purpose is to level the surface, making it perfectly flat to share the load of the overlapping elements and receive the final flooring once the screed is fully matured.
Its thickness depends on use environment, piping and service cables may be drowned inside. To reinforce and make it more collaborative it may be used an electrowelded ironnet, as in the case of soles.
The biggest problem with screed is cracks formation; this happens for following reasons:
High outside temperature, which brings the concrete present in the screed to mature (and then retreat) too quickly;
Lack of proper reinforcements in the “weaknesses” of the screed (such as near the pillars or wall corners);
Missing positioning of perimeter and expansion joints that allow the screed and flooring to “move” freely and not be tied to the rest of the structure.
Wrong water / cement ratio.
The experience and knowledge gained by Prima, prevent happening of all these problems.
PRE-MIXED TRADITIONAL SUBBASES
Concrete screeds done with pre-mixed components are easy to install, even with a pump, where machinability and setting times are similar to those of traditional cement mortars.
They are particularly suitable for the production of screeds in large surfaces. They can also be used for the production of radiant screeds without adding additives.
These premixed are formulated to control hygrometric retraction, resulting in minor cracks.
QUICKLY DRY PRE-MIXED SUBBASES
Screeds made with quick-drying pre-mixed mortars, such as Mapei Topcem Pronto and Mapei Mapecem Pronto, allow to solve the problem, common to many areas, of the difficult finding of good grain size aggregates and of fine quality, to avoid dosages errors and problems connected to labor quality, and also where there is difficulty to store raw materials (inert, cement, etc.) due to space lack.
Drying and maturing times are very low, and are therefore particularly recommended in the case of moisture-sensitive floors (wood, PVC, linoleum, etc.).
These formulated guarantees the control of the hygrometric retraction, giving rise to minor cracks.