The contents
No modern repair can not do without laying on the floor ceramic tiles, laminate or other floor coverings requiring a smooth base. Often used insulation, warm floors or split-level design decisions. A simple and inexpensive way to prepare the floor for such work can be called concrete screed – the process of casting the base with a solution of cement and sand produced for the purposes of:
- unevenness of flooring,
- raising their level,
- the device slope,
- coating heat-, sound- , waterproofing layers.
The thickness of the tie layer depends on:
- changes in floor level,
- projected loadings to the surface,
- the hardness of the base,
- the floor height in other areas,
- the availability of communications.
Usually the minimum thickness of the concrete layer is 80 mm, but when mixed in a solution of special additives it can be reduced to 40 mm.
While technically correct and high-quality device of the screed base is even, strong and durable.
The reinforcement of floor screeds ↑
When doing the reinforcement? ↑
Reinforcement is the process of strengthening of the slab with materials having higher strength characteristics.
Despite all the indisputable advantages of concrete it should be noted that it is able to collapse in case of heavy vibration or dynamic loads. To prevent this, when the concrete cover thickness more than 80 mm produces a strengthening of ties, which makes it tough, resistant to external influences, prevents cracking. With the exception of small thickness is to strengthen seams or spot the strengthening of the area that can be exposed to great pressure.
Materials for reinforcement ↑
The choice of material depends on many factors. It can be properties of the base planned value of the thickness of screed and floor loading, funding and other.
The process of strengthening layer is produced by:
- metal grid or frame,
- composite or polypropylene mesh,
- particulate reinforcement.
Metal frame is made to build the Foundation during the construction of tall buildings or when buildings are conducted on unstable ground.
For reinforcement of Metal grid welded from steel wire square mesh with a side of 100 mm to 200 mm with step 50 mm and the standard sheet size 150×200 cm or 50/200 cm.
Because the mesh should be in the layer of concrete to prevent corrosion, then, in the case of the implementation of the screed directly on the concrete Foundation, the styling is produced not on the basis, and slightly above, using the mounting props.
Composite mesh for reinforcement of the screed is made from a variety of polymers, convenient to use for spot enhancement. It is lightweight, ductile, resistant to moisture and alkaline substances. The advantages include quick installation and relatively inexpensive.
Dispersed reinforcement mesh is an innovative technology, using a sand-cement mixture is added to a fiber – special fibers of basalt, steel, polypropylene or fiberglass. The fibers are evenly distributed in the solution by stirring, and give him not only the mechanical strength but also resistance to chemical attack, shrinkage cracks when dry are not formed. This method has average prices and very good combines with reinforcing mesh.
The technology of laying of the screed ↑
For work in the room should be a temperature of about 20°C and no drafts. After determining the coating thickness and reinforcement are to commence work.
Substrate preparation ↑
If the coupler is placed on the ground, first removed the surface layer of soil, compacted substrate of expanded clay and sand with a height of 10 cm.
For installation on concrete base first is removing the old layer of concrete, rough ground is thoroughly cleaned, removed dust, dirt, oil stains, and paint. For better bonding it is applied to the primer in several layers. The perimeter of the room fixed damping tape with a thickness of 1 cm.
Waterproofing, insulation ↑
To insulate the floor, put a layer of polystyrene, expanded clay or mineral wool. To protect against the ingress of moisture into the insulation, before laying it and then on top, arrange a layer of waterproofing. For this purpose, film of polyethylene, roofing felt or vapor barrier membrane, which layers are applied overlap by 15 cm with the same plant on the wall. Then placed on top mesh for reinforcement.
Communications ↑
In this step, you place various communications, pipe, electrical wiring, perform installation of warm floors.
Laying screed ↑
To perform the work on laying of the screed, stepping back from wall 20 cm, set beacons from a solution and profile which will level off the floor height. The distance between the beacons should be on 40 cm shorter than the length of the rule. Then bring the solution to fill. The best is the ratio of cement to sand 1:3 with the addition of fibrovolokno and plasticizers.
The fill mix to start with far from the entrance corner of the room and produce parts. Each area is then rough leveled with a spade, and then the rule is carried out the final alignment on the level of beacons. When filling large areas have several expansion joints. After about half an hour the surface will be overwritten and leave to dry for a week. The first three days, the surface is moistened with water to not dry or cracked. After drying, remove the beacons, the cavity formed primed and sealed solution.
A month later, when the screed is completely dry, the surface is polished and protected with a coating of screed. This slow process of drying of concrete required to achieve grade strength M200 (class B15). Fill technology allows reducing the time of maturation of the concrete before laying the protective layer up to two weeks, which are added to the solution of special modifying additives.
The advantages of reinforcement ↑
Casting technology and conventional reinforced screeds are not fundamentally different, the difference is only the presence of the grid, which provides special benefits:
- in the reinforcement significantly improves the performance of floor is not deformed, even if completely flooded,
- by strengthening the mesh increases the resistance to tensile stress – crack formation is practically reduced to zero,
- in the reinforcement of the grid there is a possibility of reducing the thickness of the concrete and the economy of materials without loss of quality concrete Foundation,
- reinforcement mesh floor is perfect for floors with large differences of level,
- using reinforcement iron mesh evenly over the area distributed the weight of the concrete.
Requirements for concrete screed ↑
After completion of all works, the height differences on the surface, measured by two-meter rods, shall be:
- not more than 4 mm on plain surfaces,
- to 2 mm layers high precision.
When the device of such coverage necessary to fulfill the requirements of the relevant building regulatory documents such as the instructions and recommendations of the BCH-9-94, SP 29-13330-2011 and other.
As visual AIDS for reinforcement by a metal grid, you can refer to the video:
