INDUSTRIAL FLOORS

Cement screeds

Self levelling cement screeds are usually applied as a final or smoothing coat onto cured concrete floors. The technology combines water, industrial cement based dry mixtures and various aggregates according to the specific requirements (layer thickness, colour, etc.).

Self levelling cement screeds applied as a final coat provide a gloss finish surface with minimal use of joints. The finish typically lacks uniformity in colour, which would be considered a flaw in a synthetic floor coating, but in cement screeds this effect brings a characteristic look. These floors can be used not only in industrial environment, but also in commercial and residential buildings, such as shops, cafés, offices, galleries, etc.

In historical building renovations, this type of technology can complement other materials, such as stone, rough plasters, and wood. The advantage of cement screeds is vapour permeability, which eliminates the need for moisture insulation.

Compliance with technological procedures is critical for proper screed function. Essential are:

• thorough surface preparation by shot blasting to clear loose parts from the top layer, or grinding to remove a whole layer damaged by carbonation or wear until healthy structural aggregate is reached (a coarse surface is preferable to a smooth one).
• thorough base priming, by filling cracks and holes, installation of anchors, replacing whole compromised sections of material, and proper cleaning and degreasing.
• thorough insulation of existing joints in the floor and marking their positions for subsequent recutting. (The dilatation joints have to be recut 48 hours after the application of the cement screed and retain the position correspond to the placement of joints in the underlying layer.) Any objects embedded in the material – pillars, stanchions, etc. – benefit from a separating spacer.
• bonding primer application, done in two layers with different levels of dilution according to the primer specifications. The primer serves as an adhesion promoter.
• mixing and laying of the cement screed, while carefuly maintaining an even mix water ratio. (Dyed self levelling screeds are susceptible to colour changes with different mix water ratios.) The mixture is spread with a smooth or finely serrated trowel (which is always to be used at an angle to the surface, so that the coat is smooth). The screed has to be vented by a spiked roller, used parallel to the line of laying first and subsequently perpendicular to this direction.