Why do you need a blind area around the house? Do it yourself do it yourself? The blind area, in the first place, serves as a kind of protection along with a decorative function. It is installed after the end of the laying of the walls, when the time comes for external decoration. It protects the foundation from precipitation or its effects. The blind area looks like a wide strip, hermetically adjacent to the outer part of the foundation, enveloping the house from all sides. It is this house area that is subject to the greatest amount of rainfall that flows down from the roof or walls of the building, so it must be reliable, waterproof, and strong.
In addition to its direct purpose, the blind area "works" as a heater of the basement of a building.
As for the width of this protective strip, the “the more the better” rule works here. According to SNiP, the minimum width of the blind area should be at least 80 cm, while the maximum can be any - at the discretion of the owner of the house.
There are certain requirements for the arrangement of this architectural element:
- The width of the strip should not be equal to the level of the ledge of the roof, nor can it be narrower than its edge.
- The blind area around the house should be continuous.
- The protection of the foundation of a building depends on the width of the strip.
- Installation is carried out with a slope of at least 1.5 ° from the house.
It should be wide enough so that it can be walked freely without touching the walls. The most optimal width is 1 meter.
Blind device around the house
The blind area of any type consists of two layers - the underlying and waterproof. The bottom layer is usually gravel, crushed stone or sand, and the top one can be made of concrete, natural stone, paving slabs, asphalt.
The optimal angle of inclination from the house is 3-5 °, if the building is on ordinary soil, then the width of the blind area should be about 20-30 cm more than the cornice. If your home is built on subsidence or marshy soil, then the width should be at least 90-110 cm.
It is worth mentioning that some types of foundations (for example, screw and pile) do not need a blind area at all. They require the installation of a protective coating only in places where water is drained from the roof.
If the house stands on heaving soil, then it is better to make a blind area with insulation - this is necessary so that the protection does not allow moisture to pass through. In winter, the water freezes, bursts into the ground, therefore, expanded polystyrene laid in the blind area is able to prevent this factor. Extruded polystyrene foam not only does not allow water to pass through, but also has high heat-insulating qualities.
Expanded polystyrene is placed between the layers of the blind areas (a crushed stone or gravel cushion is located below), it is best to pour concrete on top or lay tiles, cobblestones. This method of insulation is very effective, shows good results.
Consider the types of blind area around the house:
- The simplest, but already practically unused material for the device of the protective strip is clay. It is an excellent water lock for the foundation of the house. Now the use of clay is no longer relevant, as new modern materials confidently occupy a leading position in the construction market.
- A protective strip made of concrete is the most common option for arranging foundation protection. It is quickly installed, has a low cost at the price of spent building materials, has a long operational period, and is resistant to manifestations of natural factors.
- The blind area of the tiles around the house is placed on a layer of sand. The tile is convenient in that it can be matched to the appearance of the building or the decorative features of the summer cottage. This type of protective strip around the house is durable, easy to install.
- Natural stone laid around the house looks very beautiful, has a long service life, but requires patience, accuracy when laying.
- The asphalt coating of the protective strip is rarely used, due to the lack of decorativeness, a specific smell when heated by sunlight and high cost.
- A waterproof protective strip is made only with a properly installed drainage system. In this case, much attention is paid to the construction of gutters from the roof, so that moisture is removed at a considerable distance from the foundation of the building. Such protection around the house works more for decorative than for practicality.
- One of the most expensive types of blind areas is made of granite. Respectable appearance, quality, durability - the main criteria of this method of protection.
It will be ideal if a drainage system is installed on the outside of the entire perimeter of the protective strip around the house (it is not necessary to make it very deep). Such a technique will protect the foundation from contact with moisture as much as possible.
How to make a blind area with your own hands around the house?
As mentioned above, the blind area consists of two structural layers - the underlying and the covering. The underlying layer provides an even, dense base for laying subsequent materials. The role of the “litter” is sand, clay, crushed stone of a small fraction. The thickness of the litter layer depends on what material the protective strip will be coated with.
The coating fulfills its main purpose - protection against water and it does not matter what material it is made of.
As an example, consider a phased construction of concrete paving:
- Initially, the marking of the future protective strip is carried out, for its arrangement we take as a basis a width of 1 meter.
- Along the entire perimeter of the house (in accordance with the markings), remove the soil layer (20-30 cm) and compact the base.
- If there are plants under the layer of removed soil, then their roots can be treated with herbicides so that later they do not begin to make their way through the coating.
- We make removable formwork from the boards.
- On a compacted soil we lay a non-thick layer of clay, and on top of it is a sand layer (about 10 cm). Clay, sand should be well compacted after laying. In the immediate vicinity of the foundation, sand is compacted especially carefully.
- We spill the sand layer with water, but not very abundantly, since clay is below.
- We lay rubble with a non-thick layer, about 6-8 cm.
- In order for the future protective strip around the house to be strong, withstand compressive and tensile loads, it needs to be reinforced. For this purpose, a reinforcing mesh with a step of 10 cm is suitable.
- In the place where the blind area is adjacent to the base you need to make a compensatory seam, sometimes it is called temperature or deformation. This seam performs a kind of protection during soil subsidence. It has a width of 1-2 cm. Thus, this gap between the base and the blind area is filled with a sand-gravel mixture or roofing material, it can also be filled with resin or foamed polyethylene (tow), sealant. Mandatory installation of expansion joints in all corners of the house.
- How to fill the blind area at home? The construction of expansion joints is simply necessary when arranging the correct protective strip around the house. When pouring concrete mass every 2 or 3 meters, it is necessary to install non-thick wooden boards set by the edge. For these purposes, ordinary wooden slats are optimal, they need to be laid so that the top surface coincides with the surface level of the concrete mass and be sure to take into account the slope! Wooden elements can be pre-treated with protective agents against decay.
- What concrete is needed for the blind area around the house? Concrete, which is used to create it, should not be inferior to its road counterpart in frost-resistant characteristics. The M250 or M300 brand is perfect, it is mixed with sand, fine gravel, water until a homogeneous mass is obtained. This mass is laid on top of the reinforcing mesh and wooden ribs, compacted (by vibration or bayonet) and leveled using the rule.
- A self-made concrete blind area around the house will become as strong as possible if you use the ironing method immediately after pouring. This construction technique has two methods - dry and wet. In the dry method, cement is sprinkled onto a freshly leveled concrete layer. It is sifted on a fine sieve. By tapping on this, the sieve is evenly distributed with a thin layer (2-3 mm) over the entire surface of the protective layer. After the manipulations, this layer is neatly compacted with a plaster blade. Dry cement draws moisture from raw concrete and, solidifying, forms additional reinforcing armor. With the wet method of ironing, the sifted cement is mixed with water to a pasty consistency, applied to the dried concrete layer with a plaster blade. The thickness of such protection is 2-3 mm. Sometimes ceresite or liquid glass is added to such a solution, but in any case, the strength of the protective layer depends on the quality of the compaction and smoothing.
- At the final stage, the concrete is covered with a wet cloth, periodically moisten it. This protects the concrete layer from drying out until it finally hardens. After 7-10 days, your concrete pavement will be ready.
You can go the easier way - save time. This method is now very popular, as it has good protective qualities, gives the house strip an attractive look.
To do this, after removing the soil layer, sand is poured into the bottom of the trench, poured on top with liquid glass mixed with a hardener. After hardening, an attractive monolithic surface is obtained, which has high moisture-resistant characteristics.
How to close a crack in the blind area of the house?
Cracks or damage to the concrete surface can also occur due to certain circumstances. Shallow cracks can be poured with a cement mortar, larger ones are pre-cut down for the entire length of the damage, and they are cleaned of litter and dust. After cleansing, the crack is poured with a mixture of bitumen, asbestos and sand.
Large damages can also be filled with fresh concrete mass, after priming them. Then they take care of the “patch” as well as a regular screed - moisten the surface until the concrete has hardened.
If the damage is serious, then additional cracks are reinforced, their subsequent pouring with a sand-cement mixture with the addition of crushed stone. After complete hardening, “latki” are treated with a primer.
Soft blind area around the house
The soft blind area does not have a top hard coating; instead, crushed stone of various colors is covered, or soil with grass is generally used. The soft blind area is not afraid of soil deformation due to freezing and subsequent thawing. When laying such a protective strip, it is not necessary to observe the angle of inclination. If a layer of expanded polystyrene is provided at the base of the soft coating, then it will additionally help reduce the depth of soil freezing in the basement area.
The blind area around the house from crushed stone is done as follows:
- The soil layer is removed, compacted, then a clay layer (10 cm) is laid over the entire area of the resulting trench. To avoid subsequent swelling, the clay should be absolutely clean, that is, not contain sand.
- Clay is also rammed, a waterproofing film is laid on top of it (with a margin). If the circumstances are such that the blind area moves away from the foundation, then the supply of film can compensate for the lack of material. The film is fixed by overlapping directly on the foundation.
- Sand is poured over the hydraulic protection.
- The next step is the laying of geotextiles over the entire area of the future blind area.
- Crushed stone is poured on geotextiles. The embankment layer may be between 10 and 15 cm.
- Re-laid geotextiles, on which decorative gravel is poured.
Thus, any blind area around the house, made with your own hands, will help to significantly increase the operational resource of your home, will bring additional aesthetics and attractiveness.