Most developers, when choosing a ground floor floor design, consider two options. The first is reinforced concrete slabs.
The second is wooden beams (logs). The fact that you can make a high-quality and inexpensive floor on the ground, many do not know.
Meanwhile, this design cannot be called new. It began to be used after the invention of an artificial stone called concrete.
We will talk about what constitutes a floor covering on bulk soil, what are its pros and cons, in this article.
At its core, the floor on the ground is a "pillow" of fine gravel or expanded clay, on which lies a reinforced slab of monolithic concrete. Ballast bedding performs two tasks:
- raises the level of coverage to a predetermined height;
- transfers the weight of the structure to the ground.
From soil moisture and heat loss, the floor is protected by a heater laid on a waterproofing layer.
The bearing basis of such a coating is a layer of soil. Therefore, the main risk factors when arranging a floor on the ground in a private house are frost heaving and moisture. The first threat is blocked by insulating the base of the foundation from the outside with sheet foam. It cuts off the cold bridge that causes water to freeze.
It should be noted that with permanent residence in the house, the temperature of the soil under it never drops below zero degrees. If the building is empty in winter, then the forces of frost heaving can cause cracks in the concrete screed and deform it. In this case, insulation of the basement is indispensable.
Protection from soil moisture is a relatively simple measure only at a low level of groundwater (2-3 meters). In damp and swampy areas, it is better to refuse the device of such a coating. The cost of waterproofing and strengthening the foundation in this case increases significantly.
For pile and columnar foundations, a slab on the ground is not the best solution. In this case, the cost of protecting the bedding from frost is higher than when using the foundation "tape".
Construction technology
There are two ways to install floors on the ground:
- Concrete preparation;
- Without a draft layer of concrete directly on the compacted base (cushion).
The first method is rarely used today. It was developed at a time when roofing material was used to protect the floor from moisture. For its gluing, a layer of concrete preparation was made (rough floor).
The second option is easier and cheaper. Modern waterproofing materials can be laid directly on the ballast without sticking to a solid base.
The process of constructing a concrete floor on the ground begins with the filling of the underlying layer. Before this, the laying of water supply and sewerage networks must be completed.
Any well-compacted soil can be used for backfilling. For this, small gravel (fraction 5-10 mm), coarse river sand or sand and gravel mixture are suitable. The pillow is poured in layers of 15 cm, spilling each with water and compacting with a manual or mechanical rammer.
Compaction of bedding with vibrotamper
To improve thermal insulation, the upper level of the pillow can be made of expanded clay gravel (10 cm). The total thickness of the ballast "pie" should be in the range from 30 to 40 cm.
Film waterproofing, laid under the insulation, needs to be protected from damage by sharp gravel and crushing with expanded clay. Therefore, the backfill is completed with a 5-centimeter layer of compacted sand. The thickness of the film laid on the ground must be at least 0.4 mm.
When laying the film insulation, its strips are spread with an overlap of 10-15 cm, fixing them with construction tape. The edges are laid on the masonry, to a height equal to the total thickness of the insulation, concrete screed and finish coating. A thermal gap 2-3 cm wide is left between the constructive "pie" of the floor, the walls, and partitions. It is filled with scraps of polyethylene foam or a special thermal tape.
To insulate the base, you can use EPS (extruded polystyrene foam), sawdust concrete or perlite concrete. Often, waterproofing under the foam is not laid, since it practically does not absorb moisture. From above it is covered with a polymer film. It protects the insulation from the destructive action of the alkaline environment of the cement mortar.
Under lightweight concrete on sawdust and perlite, a plastic film is needed. The thickness of the listed heat insulators is not the same. For EPPS, it is 50 mm. The layer of sawdust and perlite concrete must be at least 10 cm.
Having laid the thermal insulation, a concrete screed is made on its surface on a fine-grained filler (fraction 5-10 mm, thickness 10 cm). The work is carried out in two stages. First, a layer 5 cm thick is poured and a steel mesh is laid on it (cell 10x10 cm, wire diameter 3-4 mm). After that, the thickness of the screed is adjusted to the design level, determined by the calculation of the expected loads. Recommended concrete class B12.5.
This is how you get the right cake of floors on the ground with a low level of groundwater. Rough concrete preparation for hard insulation is not done. There is no real benefit from it, and the increase in the cost of 1m2 of the finished structure is very tangible.
Installation of a heating system (warm floor) changes the technology and sequence of work. In this case, first, a rough concrete preparation is poured over the compacted cushion and a waterproofing layer is laid out. Having laid the insulation (EPS), pipes are fixed to it and a leveling screed is made of concrete. Reinforcing mesh is laid over pipes or heating cable.
In passing, we note that floors on the ground can be made not only in brick, block, but also in wooden houses. With a competent approach, ballast filling does not have a negative impact on wood.
One of the options for the correct pairing of such a design with chopped walls is shown in the diagram below.
Pairing node with a wooden wall
With a low GWL, a concrete slab lying on clay or on a layer of compacted waterproofed backfill is made in the basement. This is a very common option in cottage construction.
Before the screed device, the area of \u200b\u200bthe room must be divided into strips 80-100 cm wide with a steel U-shaped profile or wooden lighthouse boards placed on edge. The damper tape is attached to the walls before the start of pouring so that it protrudes 1.5-2 cm above the design mark of the finished surface.
Concrete pouring starts from the far end of the room and moves to the front door.
Laying is carried out in stripes, filling the cells slightly above their level. For leveling, use a vibrorail or a metal rule, moving it along the beacons.
After letting the mixture dry, beacons are removed from it, filling the formed seams with fresh concrete. After that, the concrete is covered with a film and given 4 weeks to gain strength, periodically moistening with water.
Design pros and cons
When planning to make a floor on the ground, you need to know what its advantages are over other types of bases:
- Acceptable cost;
- Readiness of the basis for laying of any floor coverings;
- There is no need to ventilate the underground space to avoid the appearance of fungus;
- Greater durability compared to wooden and reinforced concrete floors.
The disadvantages of this construct include:
- Loss of usable room height (up to 60 cm);
- The complexity of waterproofing works at high GWL;
- Poor compatibility with columnar and pile foundations;
- The high cost of repairing hidden communications.
