Is it worth making a blind area for a pile foundation?

Construction requirements

Since the edging of the cottage is of a functional nature, there are official requirements for it according to SNiP (building codes and regulations). In 3.182 paragraph of article 2.02.01-83 "Guidelines for the design of the foundations of buildings and structures" it is stated that each building must have a blind area. The document also states that only waterproof materials can be used. The width of this edging depends on the type of soil.

Buildings on type I soil sag by no more than 5 cm from their own weight. Type II soil is less stable. It includes the land, buildings on which can greatly sink. For such soil, a blind area with a width of at least 2 m is needed. For type I soil, 1.5 m is enough. The thickness of the edging of the building should be at least 0.15 m. A slope is also required. It is made barely noticeable, but always more than 0.03 m.

Also, SNiP contains requirements for water drainage:

1. There should be no obstacles on the way from the foundation insulation to the stormwater network or gutters.
2. Watering taps must be installed at a height of at least 35 cm above the edging of the foundation.
3. A gutter with a width of 20 to 25 cm should drain moisture from the base of the building.
4. The requirements of SNiP will be violated if the blind area does not cover 40 cm of the sinus of the backfilled pits.
5. The flooring must fit snugly against the plinth of the cottage.
6. The slope is made from 1% to 10%. The larger angle creates a traumatic situation in winter, when the coating can freeze.

Attention! The edging of the building can be sealed manually or using mechanisms. The document does not impose any restrictions on this .. Many owners of country houses think that the blind area does not have to be done right away

This approach is fundamentally wrong: excess moisture has a constant effect on the foundation and its joints with the wall, slowly destroying the materials. In order for the cottage to last longer, you need to make the plinth facing immediately after the end of the construction of the cottage. If you leave the walls and base of the house without this flooring:

Many owners of country houses think that the blind area does not have to be done right away. This approach is fundamentally wrong: excess moisture has a constant effect on the foundation and its joints with the wall, slowly destroying the materials. In order for the cottage to last longer, the plinth cladding must be done immediately after the end of the construction of the cottage. If you leave the walls and base of the house without this flooring:

1. Moisture from the surface of the earth will penetrate directly to the foundation and soil, deforming them.
2. In winter, heaving soil, saturated with autumn precipitation, can swell.
3. Due to uneven freezing, cracks form in the foundation.

The rules specified in the SNiP documents are needed for mass construction. They are also observed in the construction of private houses in summer cottages, however, all articles then serve as a recommendation, and not as a strict restriction. Observance of such instructions ensures that the building will stand for a long time, and the foundation will not collapse due to precipitation. The requirements are detailed in articles of SNiP III-10-75 and 3.04.01-87.

Arrangement of the basement

A plinth is needed, first of all, for insulating a house, and the materials for its arrangement must have the following indispensable qualities - they must be moisture resistant, have low thermal conductivity, and scare off small rodents. The space of the base is sewn up, giving it an appropriate aesthetic appearance, using various types of decorative finishes. As the latter, you can use various types of lining, ceramic tiles, natural stone, etc.

Using ceramic tiles for tiling the base / plinth space

Thus, the pile-screw foundation and the made decorative lower part of the house are reliably protected from moisture and corrosion of metal parts.

The basement of the first floor is insulated, has a beautiful exterior finish, the choice of which is due to the taste and financial capabilities of the owner. If there is a certain height of the basement, the underground space of the house can be used for various household needs.

A bit of theory

For experienced builders, the blind area of ​​the pile foundation will seem like a rest, so much is it a simple process. I started by arranging an expansion joint. You should know that thanks to the expansion joint, I did not so much waterproof the subfloor as ensured that the base did not deform. I organized the expansion joint using a two-layer roofing material - the simplest and most reliable material.

Further, the blind area near the house is built like this: you need to dig a ditch around the house (about 0.3 meters deep) for the base cushion. I limited the ditch with the help of formwork, since I was making a concrete blind area. If someone wants to organize the formwork with cobblestone or paving slabs, he will need a concrete curb.

Each poured layer is carefully rammed and only after that the covering is laid. I also made a gutter through which moisture is removed from the house.

The rules for arranging the blind area also indicate that its width is determined by the protrusions of the roof. The blind area should be wider by 0.2-0.3 meters. The total width of my blind area was 0.7 meters. If we talk about the material of the pillow, I chose concrete.

Those who have a screw foundation blind area covered with cobblestone or paving slabs should take care of waterproofing, since moisture will penetrate through the seams and destroy the pillow. The best thing about this is the use of clay.

Why is a blind area needed around the pile foundation?

This question often arises among the owners of country houses, cottages, as well as various buildings and structures. Many of them are trying to save their money and do not make a blind area. As a result, this leads to various adverse consequences:

• damage to the material of screw piles;
• neutralization of the negative impact of frozen soil on the foundation;
• prevention of soil erosion under the building;
• deformation of the very structure of the house, etc.

The blind area for the pile foundation ensures that rain, groundwater and wastewater does not penetrate to the foundation. With its help, moisture does not penetrate into the building itself. As a result, the air stays dry and, most importantly, healthy. Especially such a protective structure is relevant if your house is built on an area where there is a weak and heaving soil.

Plus, the blind area lined with decorative stone or tiles is very beautiful. The landscape around the house becomes aesthetically pleasing and complements the design of the building itself.

Below is a table with the approximate cost of work on the installation of the blind area:

The main mistakes of individual developers

When erecting a buried foundation of a house, a pit is torn off on the site, the sinuses of which are later covered with inert materials. To make a shallow or shallow foundation on clay soil on your own without violating the joint venture, it is necessary to take a set of measures to reduce the heaving forces. Therefore, heaving soils of the base are replaced by an underlying layer of crushed stone or sand.

In any of these options, a man-made zone is created, in which the aquifer is inevitably collected, since the permeability of nonmetallic materials in the underlying layer and filled up sinuses is much higher than that of natural soil.Therefore, any moisture near the basement of the dwelling will accumulate underground and destroy concrete structures. The blind area tape should be wider than the sinuses of the pit and the overhang of the roof, and a storm drain (trays, gutters, point rainwater inlets) should be integrated into its outer edge.

When making a blind area, an individual developer often makes mistakes:

• clay castle - this material really does not let water through from the outside, but it absorbs it and sharply increases in volume when freezing, which results in the destruction of the concrete screed or asphalt;
• insufficient width - in the absence of a roof drain, water flows freely erode the soil near the edge of the blind area, penetrate the ground, damage the foundation of the house, in the concrete structures of which multiple cracks open;
• rigid connection of the blind area with the foundation - residual heaving forces cannot push a heavy floating slab, MZLF tape or grillage pillars to the surface, but easily lift the blind area, which seeks to break the foundation or tilt it;
• lack of insulation is especially important for dwellings of temporary and seasonal use, houses with overlapping logs, since the soils adjacent to concrete structures freeze and swell.

Be sure to make expansion joints.

The existing opinion that the blind area should be created at the stage of landscaping or landscape design at the end of the construction of the building box and roof is erroneous. Heavy rainfall is possible even during the construction season. With a "long-term" construction, the foundation remains unloaded during the winter. These factors negatively affect the resource of the underground structure, therefore, the blind area should be poured immediately after the completion of the zero cycle, waterproofing and insulation of the outer edges of the tape, slab or grillage pillars.

A properly made blind area should adjoin the foundation through a damper layer. A special elastic tape must be installed between these structures.

What is a blind area for a pile foundation, is it needed + step-by-step installation instructions

The pile foundation is a reliable and durable type of supporting structure.

It is able to solve the problems of waterlogged or unstable soils, which occupy a large area in the northern regions of Russia.

The specificity of the pile foundation lies in the creation of support rods that are immersed to a sufficient depth to reach dense soil layers or to achieve sufficient bearing capacity of the rods due to the high frictional force.

The building receives a solid and reliable support, practically independent of heaving loads or other soil influences.

The condition and performance of the piles largely depends on the improvement of the site adjacent to the pile field.

Decorative finishing

The second part of our protective sidewalk has a decorative purpose, and its appearance is determined only by the aesthetic tastes of the owner of the building. Asphalt, cobblestone, paving stones and paving slabs are most often used as this type of finish. At the same time, you need to remember the need to create a slope of about 5-7 degrees to organize the drainage of moisture towards the ground.

The use of paving stones

Most often, the blind area of ​​the house includes paving stones or natural stone. The technology of their application is as follows - a layer of sand is poured onto the bottom of the trench, compacted tightly and poured with a 5 cm layer of concrete. Then, a reinforcing mesh is laid on this layer and another pouring with concrete is made.

After the solution hardens, it is covered with a dry mixture of sand and cement and paving stones are laid on it. The outer edge of the paved paving stone is formed by a border. This blind area is very reliable.

Paving slab cladding

In the case of using paving slabs as facing, the technology of its laying is similar to that of paving stones.

Using paving slabs for cladding

Thus, the answer to the question of whether a blind area is needed for pile-screw foundations, upon careful study, can be only one - "yes", but at the same time it is necessary to take into account a number of differences in its arrangement in the case of using, for example, a strip foundation.

Below are links to the relevant thematic videos on the manufacture of a blind area with a pile foundation. Thus, the absence of a rigid connection with the foundation on the piles and careful observance of the technology of its manufacture (first of all, it concerns the materials used), the main requirements, along with their high water-repellent properties. The decorative part of the design entirely depends on your desire.

The blind area with a pile foundation must be performed without fail. It is needed so that a residential building on such a foundation is well protected from the negative effects of precipitation and groundwater.

How is the blind area for the pile foundation made

Conventionally, the blind area for the pile foundation can be conditionally divided into two layers:

1. An underground layer consisting of various materials (gravel, crushed stone, sand, etc.), which allows moisture to be reliably removed.
2. External blind area around the pile foundation. It performs not only a decorative function, but also gives strength to the entire structure, which determines its durability.

Building materials

In addition, you will need to select exceptionally high-quality materials that will cope well with the tasks.

Choosing a material for the blind area

In order for the blind area around the house on screw piles to be not only reliable, but also aesthetic, it is necessary to take a responsible approach to the choice of materials. For the underground layer, a standard set is usually used: gravel, crushed stone, sand, clay. As for the outer coating, there is a great variety.

Variety of options

The most popular are:

Crushed stone. Is one of the most affordable materials

It is very simple and quick to organize a blind area around the house on screw piles with the help of crushed stone.

Concrete
It also refers to simple and affordable options, but in order to prevent cracking, it is important to pay special attention to the installation technology and take care of high-quality expansion joints.

Paving stones. Differs in high decorative characteristics
It is possible to choose the color and type that best matches the overall exterior

Installation is quite difficult, but step-by-step instructions allow you to do everything yourself.

Paving slabs. It also allows you to create an attractive appearance, while it has high strength characteristics.

Layout and excavation

First of all, you should dig a trench approximately 30-40 cm deep, but possibly more, depending on the type of soil. As mentioned above, the width is individually calculated for each specific case. The main thing is that the blind area of ​​the pile foundation protrudes beyond the edge of the roof.

Excavation

After the trench is ready, you should place the pegs around the edges and pull the twine or fishing line between them, to which the orientation will be carried out. Also, at this stage, the soil should be compacted. To do this, use clay without impurities, which is placed on the bottom and carefully tamped.

Blind area manufacturing

Next, the remaining layers are filled in: roofing material or other waterproofing material, a layer of sand and gravel

As with any other, on a pile foundation, it is important to take care of the drainage system. To do this, an additional swarm is dug along the edge of the future blind area of ​​the pile-screw foundation, where sand, geotextiles and a perforated pipe are laid

Gravel is poured on top and a geotextile layer is laid again.

Only after carrying out all of the above measures can you start laying the finishing decorative coating. First of all, formwork is being built around the perimeter of the blind area. Then the concrete solution is diluted, and the path is poured. Only after the mixture has solidified can the formwork be removed, and the expansion joint can also be repaired. This is done by backfilling fine gravel or sand into the existing cracks.

The final stage is the installation of the decorative coating. The installation process will depend on the material chosen.

Laying decorative coating

Reinforcement is required when using paving slabs or paving stones. Also, the original option will be the use of turf. The organization of an attractive path or flower bed is an original idea. A dacha with this design will look stylish and aesthetically pleasing.

Why do you need a blind area

Without edging made of waterproof material, the walls and foundations of the country house are constantly exposed to moisture. The blind area consists of several layers. The first is the bottom one. It is made from a mound of gravel and sand. The reinforcement mesh supports the frame of the edging, keeping its shape. The litter should be placed directly on the ground, which is being leveled beforehand.

The top layer is needed to waterproof the foundation from excess moisture. It also acts as a decoration. If you choose the right materials and style, the blind area will help you arrange a summer cottage. This function is no less important than the protective one. The aesthetic pleasure from the view of the beautiful courtyard complements the rest and makes it more efficient. The waterproofing must fit tightly to the building so that moisture does not seep into the foundation.

Attention! To drain water, the edging around the cottage is made at an angle to the outside.

The blind area of ​​a country house is needed for:

• protecting the building from cracks due to temperature changes in winter;
• isolation of the basement part of the building from excess moisture;
• preserving the shape and integrity of the house;
• prevent foundation creep;
• prevents the roots from destroying the base of the cottage;
• reduces the rate of foundation wear;
• reduces the need to repair the base of the house;
• complements the style of the garden area;
• retains heat and prevents sudden changes in temperature;
• simplifies movement along the house;
• creates moisture wicking during rains and melting snow.

Waterproofing of pile and columnar foundations

The pile foundation is used in areas with restless soil. Its structure consists of piles that are driven deep into the soil, until a dense layer is reached. And from above they are united by strapping beams or slab grillage. Waterproofing a pile foundation is very problematic. If the waterproofing compound is applied to the concrete part of the piles before driving them into the ground, then it will peel off from friction with the soil. And it is impossible to process piles driven into the soil with a moisture-proof composition. Therefore, for the impregnation of the concrete part of the piles, a hydrophobic composition is used during the production process. In the future, it can be treated with impregnations and coatings, which will increase the degree of protection against moisture.

Columnar foundations are used in the construction of buildings with light walls. Pillars made of reinforced concrete, rubble concrete are placed in the prepared pits, or the technology of pouring concrete into the formwork is used. For waterproofing a columnar foundation, methods typical for a strip foundation are used.

Since the grillage that connects the piles and pillars is a full-fledged part of the foundation, it also requires reliable waterproofing. The grillage can be made either in the form of a tape or in the form of a monolithic slab uniting all pillars or piles.

Waterproofing of the pillar foundation grillage

To make a pillar foundation grillage, waterproofing is applied to the pile heads, then sand is poured up to the upper edge of the piles, roofing material is spread on the sand and wooden formwork is installed.It is sheathed from the inside with roll waterproofing, filled with reinforcement and poured with concrete. After the concrete has hardened and the formwork and sand have been removed, all parts of the grillage must be carefully treated with a waterproofing material. Before this, the surface of the grillage must be leveled and cleaned. It is possible to use coating technology or pasting on heated bitumen.

Waterproofing of the pillar foundation grillage

Waterproofing of slab foundation grillage

The grillage of a slab foundation is made similar to the grillage of a columnar foundation, only the formwork is a large box with a bottom, which is installed on the pile heads. After the concrete dries, a monolithic slab is obtained, which connects the foundation together. The entire grillage must be waterproofed with rolled roofing material and hot bitumen. Before applying waterproofing, you need to make a screed from the solution.

Protection of a columnar foundation with a fill

To prevent moisture from getting under the space between the grillage and the ground, a pick-up will be required. This is a kind of basement version, which is made of wood, timber, brick or stone. The fence will reliably protect the base of the building from rainwater and snow. It is installed as follows:

1. A shallow trench is dug between the piles, about 30-40 cm.
2. Sand and gravel are poured inside in a small layer.
3. A timber or brick is laid on this pillow to the base of the house.

If the intake is equipped with all the necessary ventilation holes, then moisture will not accumulate under the house. Waterproofing is required on the outside of such a plinth to provide protection against surface water. For this, rubber-bitumen mastics are used.

In addition to protecting it from moisture, it helps in keeping warm in a house with columnar foundations. There is a separate detailed article on how to make a warm filling on our website: insulation of a columnar foundation.

How to build a reliable blind area with your own hands

The device of the blind area has its own subtleties, but this work can be done independently, having some construction skills, it is not at all difficult to do this.

It is worth noting that the blind area consists of two layers:

1. Top cover - it is necessary to make a path around the house from reliable materials that do not allow water to pass through. Usually, the choice of material remains with the owner of the house, who is guided by his own taste and financial capabilities.
2. Underlayment - this layer is required to be made of clay, crushed stone or pebbles, coarse sand is also used. The device of the underlying cushion is performed with the obligatory compaction of the materials used.

We recommend watching a video on how to build a blind area with your own hands.

Laying technology

A shallow trench is dug along the perimeter of the house, the depth of which depends on the materials used. During excavation work, old roots, stumps, and construction debris are removed from the ground.

Plastic clay is laid at the bottom of the trench, carefully kneading the clods and tamping the layer. A layer of waterproofing material is laid on top of the clay castle, then a gravel-sand mixture is poured. The backfilled layer should be tamped thoroughly.

If the blind area is performed on an area with a high groundwater level, a drainage system is definitely needed, which will not allow rain and soil water to accumulate near the walls of the house. Drainage can be done in different ways, but for reliability, you need a special drainage pipe with holes.

Watch the video on how to install the drainage system at the same time as installing the blind area.

Drainage pipes are laid below the outer edge of the blind area, for which a separate trench should be dug, in which a sand and gravel base should be provided at the bottom. Pipes with perforated walls are insulated with geotextiles.Water from the pipes will flow into a special well, which will also need to be made on the site.

At the junction of the basement surface with the blind area, it is necessary to provide for a gasket made of moisture-resistant building material, which will prevent damage to the basement during seasonal soil movements.

Basic rules for building a blind area at home

The bosom or the space between the soil, untouched when tearing off the foundation pit under the house or the trench under the tape and the foundation itself, is covered with soil. This operation is called backfilling. In this case, the layer directly next to the wall can be covered with clay and tamped. Lay the clay layer just below the ground level, for example, by 100 - 150 mm. The "thickness", or rather the width of the clay castle at the level of the base sole, should be at least 250 - 300 mm. As backfilling progresses, this width can increase up to 400 - 500 mm. Further away from the walls, there may be ordinary soil.

All backfill must be compacted in layers. Around the whole house it is necessary to leave an uncovered "groove" up to 150 - 250 mm deep. Coarse sand or screenings with a slope of at least 1.5 - 2%, that is, at least 20 mm / m, are poured into the groove as a sublayer, which are leveled and tamped. Sublayer thickness 50 - 80 mm.

There should not be a rigid connection between the monolith of the blind area and the wall of the foundation or basement. Very often, especially in loose soils, a monolithic blind area can move relative to the basement. In this case, the destruction of the waterproofing layer of the base and basement is possible, and during rains or in spring, when the snow melts, it will freeze.

To prevent this, when concreting the formwork, two or three layers of waterproof material must be laid between the waterproofing and the end of the protective layer. You can use two strips of roofing material or thick polyethylene, laying them on tamped sand or screenings, lifting them along the wall and securing the upper edge.

If the waterproofing layer is extended under the entire formwork and brought out into the drainage groove, then you can use materials that allow water to pass through - a layer of rubble, pebbles, paving slabs, paving stones, etc.

After that, a layer of concrete is laid at least 50, and preferably 70 - 100 mm. When concreting, it is advisable to use a mesh of reinforcement with a rod diameter of 3-5 mm and cells of 100 x 100 or 150 x 150 mm.

After about 4 - 6 meters, an expansion joint is made so that the concrete does not burst in winter or bulge in the heat in summer in cold weather. In the area of ​​the expansion joint, it is worth laying on the backfill two layers of waterproofing - roofing material or thick polyethylene with a width of 700 - 1,000 mm. Fill it with bituminous mastic, sealant or even sand.

A drainage groove is made along the outer edge of the layer below its surface to drain storm water. This can be a groove in the ground, in the form of a concrete strip, or from concrete blocks.

This is how the correct foundation blind area is made.

If you have the necessary tool and skills in owning it, then having bought the necessary materials, you can make a blind area of ​​the foundation with your own hands.

Preparatory work

For any type of blind area, a ditch is needed. It is pulled out with a slight slope (about 3 ° -5 °) to the outside. The moat should be close to the foundation of the main structure. Before starting work, you need to check all measurements. To make the ditch even, pegs are attached at the corners, to which a rope is tied at ground level. The hole needs to be dug along the lines obtained.

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Before making an embankment, the bottom of the resulting ditch must be tamped. The easiest way to do this is on clay soil. The soil, in which there is a lot of sand, does not hold its shape well. To align it, you need special equipment. It is impossible to make a blind area on rainy days, so it will not work to wet and tamp the embankment. You can solve the problem by adding a little cement to the ground. Straighten the resulting mixture and pour a little from the watering can.Then you can level the layer with your feet or a straight board. It is impossible to make a blind area until the soil is completely dry.