screed floor is a dry mixture.This mixture was used in the construction instead of traditional materials such as concrete or cement-sand mortar.
screed floor must meet certain requirements, such as strong adhesion with the underlying layer, the strength should not be cracking, smooth surface, conform to sanitary requirements.
type-screed floor can be divided into:
- Monolithic or stapled.Before laying screed must be primed with a special aqueous dispersion of the base polymer.It is necessary to avoid water absorption.This type of screed can be laid directly on the floor, with a minimum screed thickness should be 20 mm.Compression strength must be at least 15MPa.
- Ties to the separation layer.They are used in places where there are increased requirements for waterproofing.It is placed on a special separation layer, such as bituminous paper, etc.This prevents the adhesion of the screed to overlap.The thickness of such ties have Bat not less than 30 mm, the compression strength of 25 MPa.
- Floating screeds on the insulating layer.They are not associated with the base.Stacked on a special proofing layers that cover the heat and sound insulation materials.The thickness of such couplers, made of cement by 40 mm.The flexural strength should start from 2.5 MPa.
- Floating screeds for underfloor heating.Stacked two layers.The first is usually laid to the top of the heating pipes.Second poured to a height of 25 mm from the first.The second layer is laid only the setting of the lower layer.The thickness should not be less than 35 mm, and a compressive strength of 25MPa.Such a floor heating can be started only after 21 days after application of the second layer.
Just tie can be divided by type of binder layer:
- Cement.They are used for all types of premises and of any building.They are based - hydraulic binders.The thickness of from 30 to 35 mm, the strength must be 4 weeks under compression of 25 MPa.
- gypsum or anhydrite.May be used everywhere except in premises which can be high humidity.The basis of these ties - alpha-CaSO4x0,5 H2O and anhydrite CaSO4.Must withstand the compression of at least 25 MPa, and at a bend - 3.0 MPa.
- Magnesia.In areas where it is necessary to use those ties to isolate all the metal parts, as they can absorb moisture and have a corrosive effect.The basis of these ties caustic magnesite, bischofite solution, organic or mineral fillers.Ties must have a compressive strength of not less than 10 MPa and bending - not less than 2.5 MPa.
Dry mixes, Portland cement based, is often used.Fillers are quartz sand with grain size from 0.5 mm to 2 mm.The ratio between the binder and the filler should be one to two.Functional additives should not exceed 5%.Just to be a plasticizer that provides a relatively high mobility of the mortar.More needed water retention additive that prevents segregation and does not allow them to absorb moisture mortar base.
its strength screed should get no more than 24 hours.If the slope of the screed is necessary, the ceilings on the use of fiber .. To apply the cement screed is very important qualitative base and its preparation under the screed.
screed quality control is a property as spreadability.This property is evaluated strength, resistance to cracking, and all the rest.To do this, take the cone looks its free rasplyv (the consistency should be normal by GOST 310.4).This rasplyv should be 130 - 150 mm after 1 minute, lifting the cone.