The construction of a building begins with the construction of the foundation; at this stage it is determined where the vents will be made, in the foundation or in its base. Vents in the foundation of a wooden house are special ventilation holes in the above-ground part of the foundation, which are made in order to prevent the appearance of dampness in the basement (underground) in the summer and the accumulation of natural gases such as radon. That is, their direct purpose is ventilation under the floor on the first floor.

It is worth noting that the basement rooms must be connected for air exchange (air circulation). As a rule, ventilation ducts are located in the foundation or its base under the basement floor or below. Vents are usually closed for the winter.

In the summer, when moisture and gases accumulate in the basement of the house and evaporate from the soil, part of the foundation and the lower part of the floor of a wooden house becomes overgrown with mold and starts rotting processes. That is, if you do not make a vent in the foundation, it will quickly begin to grow mold and slowly collapse.

Proper production of ventilation

Installation of vents before pouring the foundation, material used – plastic pipe for ventilation

To have a dry basement, good ventilation is necessary. Such ventilation in the foundations is included in the design when organizing the formwork. To organize the vents, it is necessary to take into account their location above the ground. The height of the vents from the surface should not be less than 30 cm, so that in the spring melt or rain water does not leak through them.

It is likely that in some cases, the ventilation holes will need to be made higher if the height of the foundation allows. It all depends on the climate and the amount of snow. Please note that wooden beams cannot be used to organize ventilation. For vents, it is better to use plastic or asbestos pieces of pipes with a diameter of 110-130 mm, mounted in concrete (at the stage of pouring it).

In addition to moisture, radon can accumulate in the underground space. Most moisture and gas enter there in winter. After all, the soil under the house does not freeze. To prevent such problems from arising, they arrange vents.

Boxes and beams are pulled out from the foundation no earlier than a month after it is laid. During this time, they “stick” to the concrete, and it is difficult to knock them out. For this operation you need to perform the following steps:

1. After the concrete has dried, take a metal drill and drill into the block on both sides, in the center or around.
2. Then take a wood drill and drill a hole through, and the drill should not be more than 2.5 cm.
3. Having made a through hole, you need to use a semicircular chisel to expand the hole from the center in any direction.
4. Then, using a straight chisel, the frozen side is beaten off.

The procedure for removing beams clogged in this way is quite labor-intensive. Therefore, it is better to use other methods, for example, vents can be made using metal boxes instead of bars, since it is easier to knock it out of the foundation. You can also use sewer pipes for this. In this case, the ventilation vents are positioned strictly one against the other.

Peculiarities

Making air vents in a finished cottage structure

For high-quality arrangement of the ventilation subfloor, the windows are covered with special lattice covers (made with your own hands from meshes or gratings). This is done to prevent animals from entering the house through the vents. The diameter of the boxes is selected in proportion to the ventilation covers. If the vents are not made in advance, they are drilled using diamond core bits.

The shape of the holes can be very different: square, round, triangular. But, as a rule, they are made rectangular. The vents must be positioned evenly, at equal distances from one another. If the house is cold, it is better to close the holes. But in wooden houses they are not closed under any circumstances, especially if the house is new.

If there is no ventilation or blocked openings, you may incur costs associated with repairing the foundation or cleaning the walls from the resulting rot and mold.

A little about the positive aspects

Unlike other methods of organizing ventilation, vents have much more advantages. The main ones:

• long service life;
• low price;
• reduction of heat loss;
• environmental cleanliness;
• practicality.

None of the other methods of ventilation can compare in efficiency and practicality with vents.

Calculation

The optimal number of ventilation windows should be one per 2-3 meters. It is worth considering where the wooden house is located; if it is located on a hill, then two vents will be enough, for a house in the lowlands from four. It is advisable for homeowners who are building a house to know the local wind rose diagram (a diagram of the wind regime in a certain place based on long-term observations) so that the ratio of air flows on each side is not a problem. Let's look at an example of how to make the calculation.

Let's say the dimensions of the foundation are 5 by 6 meters. The planned dimensions of the vents, which have a rectangular cross-section of 20 by 25 cm. It is necessary to calculate the minimum permissible number of windows and correctly position them along the walls.

The required area of ​​the vents is determined by the formula:

S = F/400 = 30/400 = 0.075 m2,

where: F – basement area.

The required number of vents is determined as follows:

N = S/P = 0.075/0.05 = 1.5 ≈ 2 pcs.

where: P = 0.2x0.25 = 0.5 – area of ​​one vent.

It turns out that you need 4 holes to avoid unventilated “bags”. They can be placed on the short or long side of the house. But the best ventilation will be if the vents are located on the short sides. The height above the ground is not lower than 30 cm from the ground.

Ventilation in a wooden house

Option for a finished product in the foundation of a private house

Ventilation of the foundation of wooden houses is arranged in embedded foundation beams. They are usually cut down between the first and second crowns, or between the foundation and the floor log. They do this like this:

• mark the places where there will be ventilation vents;
• make cuts in embedded foundation logs;
• make the holes in the form of boxes.

This work can be performed by specialists if necessary. Especially if you need to do the vents after you forgot to do them in advance.

Made on screw piles, it consists of decorating the base of the supporting structure of the building. Finishing is the final stage of building a house.

Cladding a foundation on piles can be done in the following basic ways: creating a suspended plinth, creating a strip foundation around the perimeter of screw piles, cladding with plinth siding, finishing with natural stone, cladding a screw foundation with mosaic plaster.

Screw foundations are widely used in the construction of light structures. This type of foundation is universal due to the fact that it can be installed even on unstable soil, where the groundwater level is high, on slopes and near trees.

Facing the foundation on piles can be done in the following basic ways:

1. Creating a suspended plinth.
2. Creation of a strip foundation around the perimeter of screw piles.
3. Cladding with basement siding.
4. Finishing with natural stone.
5. Cladding the screw foundation with mosaic plaster.

Each method has its own advantages, and differs in cost and amount of work.

Creating a suspended plinth

The essence of this method is cladding with sheet finishing materials that are attached to wooden or metal guides. This technology consists of the following stages:

1. A sheathing is made, which is secured to screw piles using self-tapping screws. Metal profile pipes 40x20x2 mm or wooden boards 40x100 mm in size, pre-treated with an antiseptic, are used as guides.
2. The corners of the guides are processed: the protruding parts are cut off and connected to the perpendicular ends of the counter boards using a profile angle.
3. A small gap must be left between the sheathing and the ground to avoid damage during ground movements. This gap should be within 5-7 cm. The gap can be closed with a metal mesh so that pets cannot get under the house. Thermal facing panels are attached to the resulting sheathing: stone panels, slate sheets, facade slabs, asbestos-cement slabs.
4. Finally, drips, ebbs, and metal corners are installed. For good ventilation of the subfloor, it is necessary to provide special vents.

The arrangement of a suspended plinth is justified by its following advantages:

1. Economical. A suspended plinth will cost 3 times less than installing a strip foundation.
2. Small amount of work and simplicity of the method.
3. The hinged plinth provides good ventilation and protects the underground space from dampness, which prevents the formation of mold on the foundation.
4. Aesthetics. Thanks to modern finishing materials, the foundation can be given an imitation of natural stone, marble, or wood.

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The technology of this method consists in arranging a shallow strip foundation along the entire perimeter of the pile-screw foundation of the house. Brick or cinder block masonry is laid on this structure, so that it can then be lined with decorative materials. The sequence of operation of this technology is as follows:

1. Dig a shallow trench around the perimeter of the base of the house and fill it with concrete mortar.
2. Perform brickwork on a strip foundation.
3. Create an outlet by placing masonry under the log.
4. Finish the façade of the plinth. For this you can use thermal panels, plaster, “wet” facade, etc.

The advantages of a strip foundation are:

1. An additional concrete foundation provides high strength to the structure.
2. Insulation. Compared to a suspended plinth, a strip foundation creates an air gap that regulates temperature well.
3. Aesthetics. Modern finishing materials create a unique imitation of natural stone or other premium materials.
4. Cladding with a strip foundation makes it possible to build a basement.

In addition to the listed advantages, there are a number of restrictions on the use of this finish:

1. Creating a brick plinth is dangerous on moving soils.
2. A strip foundation cannot be erected on a site with a large difference in height.
3. This method is quite expensive.

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Natural stone finishing

Facing the foundation with natural stone is a reliable, expensive and elegant method. This method is suitable for both foundations on screw piles and other types of foundation.

The advantages of this finish are enormous:

1. Durability and strength.
2. Protective properties and resistance to mechanical damage.
3. High resistance to moisture, ultraviolet radiation and dust.
4. Environmental Safety.
5. Color range for every taste.
6. Classic decorativeness.

The disadvantages include:

1. High cost.
2. Difficult installation.
3. Special care.

Only durable types of stone are suitable for finishing the foundation: granite, labradorite. It is better not to use marble and limestone, since these materials are quite soft and porous and their protective properties weaken over time.

Do you know the main difference between frame houses from Russia and frame houses from the USA and Canada? They differ in foundation. In Russia, to reduce the cost of construction, pile foundations are actively used for light frame houses. But, unfortunately, this type of foundation is completely unsuitable for houses intended for permanent residence. And in the USA and Canada, the basis of any house is a concrete foundation (often with a basement floor) - the so-called basement.

Why is that? Let's find out!

The main problem with a pile foundation is that you voluntarily increase the heat loss of your home. Exactly the same story awaits you if you make a strip foundation and leave a ventilated subfloor (instead of insulated floors on the ground).

When there is soil under the floor of your house, its temperature, as we know, is constant throughout the year and is approximately +7 degrees. As soon as you raise the floor into the air (on stilts or tape), the temperature underneath becomes close to the street temperature. That is, in the first case, your temperature gradient does not change throughout the year and is approximately 15 degrees (+22 indoors, +7 ground temperature). In the second case, during a cold winter, the temperature gradient between the floor indoors and outdoors will be more than 40 degrees! That is 2.5 times more. And these are the most natural heat losses.

If we take a standard one-story 10x10 house with a ceiling height of 3 meters, it turns out that by raising the floor above the ground we increase the area of ​​enclosing structures that come into contact with the cold environment by 30%. And if we want the floors in such a house to be warm, then we will need to use 300-400 mm thick insulation (and if we make floors on the ground, then we will need 2 times less insulation).

You can object and suggest insulating the base around the perimeter. Yes, you can do this and at first nothing bad will most likely happen. But if you do not leave any ventilation, then all your logs will quickly rot from moisture, and if mistakes are made during the installation of vapor barriers, the mineral wool insulation will become saturated with moisture, which will lead to it no longer performing its functions. And if you make ventilation, the air temperature under the floor will practically not differ from the outside temperature.

For this very reason, a foundation on metal piles and a house for permanent residence are completely incompatible things. And I’m not even touching on such issues as shaky floors (if the performer saved on deepening and tying, which is found everywhere) and the need to climb several steps before entering the house from the street (the lower the entrance to the house from ground level, the better ).

A foundation made of metal piles is justified only in one case - you are building a tourist center and its remoteness from civilization does not allow you to bring concrete or cement to make a monolithic foundation. Or if you want to build a seasonal cabin for weekend getaways. Also, you can’t do without a pile foundation in the permafrost zone, but that’s a different story.

If you are building a house for permanent residence, forget about the pile foundation. And forget about the strip with wooden floors too. Use the type of foundation in which your floors will be in contact with the ground (through the insulation). Of course, you can make a strip foundation with insulated floors on the ground, but if it is possible to make a USHP-type foundation, there is no point in messing around with floors on the ground (this is more expensive and more difficult). If the terrain does not allow the use of a slab foundation, make a concrete basement. The same applies to cases when you definitely need a house with a basement. In exceptional cases, it is possible to build a house on reinforced concrete piles.

You can read more about why a permanent house needs to be built on a foundation such as an insulated Swedish stove.

Addition: Since you are constantly asking me what I think about standard modular houses on screw piles, I will insert here this video, which I already showed in the comments:

Literature for self-study:
Värmeförlust genom platta på mark - en jämförelse av kantbalkar

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There are several opinions about pile-screw foundations. Some consider this option ideal for relatively light frame houses and log houses, while others criticize it, citing their own arguments. Let's together understand the myths that exist about foundations on screw piles.

Myth one: a pile-screw foundation is unreliable

In fact, there are reviews from homeowners that a house built on screw piles wobbles, sways, and the piles themselves begin to protrude. So, unreliability is not a myth at all, but the pure truth? Not really. If problems arise with a house built on a pile-screw foundation, it means the construction technology was violated! We wrote about what the optimal size of screw piles should be. In addition, the reasons for instability of the house may be:

• Insufficient depth of piles;
• The diameter of the piles is not large enough;
• Excessively deep pit;
• Small number of piles;
• Weak-bearing, too soft soil;
• Errors in calculating the load on piles.

If all technologies were followed, calculations were made accurately, and installation was carried out by professionals, there will be no problems with the pile-screw foundation! In this case, it will be possible to say for sure that the unreliability of such a foundation is a myth.

Myth two: a pile foundation can be erected in just a day

Of course, installing screw piles is much faster than pouring a concrete foundation. However, this is not to say that you can cope in just a day! This is not always the case. Firstly, professionals always carry out test drilling and test screwing. This is necessary to find out the characteristics of the soil. It may be weak-bearing, too hard or rocky. The presence of stones in the soil will seriously complicate the screwing of screw piles, and in some areas the soil can be so strong that even metal will not withstand. In addition, sometimes it is impossible to use a drill and other special equipment on the site. In this case, the construction time for the foundation is also delayed.

Myth three: screw piles will rust within 10 years, the house will not last long

Experts say that a correctly selected screw pile will last at least 50 years. Service life depends on the following parameters:

• steel grades;
• metal thickness;
• quality of metal protection - painting, galvanizing, anodizing;
• soil aggressiveness.

In saline and acidic soils, metal rusts faster. In addition, special paint should be used to protect it and an anti-corrosion coating should be provided. You should not use cheap compounds.

Myth four: during installation, the blades of the pile may break off, causing it to sag

This can only happen in two cases - low-quality screw piles were initially selected and the installation technology was violated. If the soil is strong, rocky, and the installation was carried out harshly, then, of course, the blades can be broken. However, if you choose high-quality piles and do everything according to the rules, there will be no problems.

Myth five: you can install a pile-screw foundation only in the warm season

Not true! In winter, the soil, of course, freezes, but a small top layer can be removed using a chipper and you can easily install piles. Experts say that in winter it is often even easier to work, and no potato beds interfere with the plot. As for pouring concrete at sub-zero temperatures, we have dedicated this topic.

Myth six: screw piles are a new technology, not yet proven by time

In fact, pile foundation construction has been known since ancient times. True, then the piles were driven into the ground. In 1833, Irish civil engineer Alexander Mitchell patented a device called the "screw pile". Unlike conventional piles, screw piles are screwed into the soil. Initially, such piles were used for the construction of piers and lighthouses, then the scope of application expanded significantly.

In Russia, screw piles have been known since the beginning of the last century, in particular, they were widely used in the field of military construction, in permafrost conditions. That is, we are not talking about any new product! Research in the field of application of screw piles has been carried out more than once, including in the USSR, the advantages of this technology have been proven by specialists. True, screw piles began to be used in Russian low-rise residential construction later; previously they were considered the prerogative of the construction of industrial and military facilities.

Myth seven: all screw piles are the same, they differ only in price

Absolutely false. Piles differ not only in quality, size, metal thickness, and the presence of corrosion protection, but also in their scope of use. For example, there are piles created specifically for heaving, waterlogged or permafrost soils. In addition, they can be cast or welded. So you should choose based on your needs, preferably in consultation with specialists.

Myth eight: you can screw in screw piles without a pit

Professionals consider this a violation of installation technology, recommending that a small pit be made. This is due to the fact that the top layer of soil is usually the loosest, and the blades of the pile at the first stage loosen the soil until they reach denser layers. Often, without a pit it is completely impossible to screw in a bladed pile. In addition, concrete can be poured into the pit to strengthen the structure.

Myth nine: screw piles are ideal for building a house on a slope

Yes, this option occurs quite often. However, a house on a slope can also stand on other types of foundations; before choosing a foundation, it is important to conduct geological surveys. A pile foundation may be the simplest choice in this case, but it is by no means ideal.

Myth tenth: the floor of a house on a pile-screw foundation will be cold

This myth is connected with the fact that cold air will circulate under a house standing on stilts. However, if the floor is reliably insulated, the problem can be easily solved. And ventilation, by the way, will prevent the floors from starting to rot.

Filimonov Evgeniy

Reading time: 9 minutes

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Frame house on screw piles

How to create a frame house on screw piles, a variety of piles, the necessary tools. Advantages and disadvantages of a foundation based on screw piles.

How to create a frame house on screw piles. The design of screw piles, their advantages and disadvantages. Construction of screw pile foundations, cost of a screw foundation. Basics of creating a frame house on screw piles. A variety of screw piles, determining the number and size of supports. List of necessary tools. How to build a foundation on screw piles. Technology for constructing a pile foundation using the strapping method.

Criteria for choosing screw piles for a frame house, installation of a screw foundation for a frame house. How to perform the bottom frame of a frame structure, construction of a foundation, arrangement of a pile-type foundation, frame, walls and roof. Nuances of designing a house on screw piles.

Frame construction technology allows you to build a full-fledged house in a short time at relatively low costs. Frame houses are lightweight (350 - 370 kg/sq. m), which makes it possible to avoid expensive strip foundations. One of the most economical options for foundations for light frame buildings are screw piles, which we’ll talk about today.

Screw piles for a house are made from metal pipes. One end of the pipe is given a conical shape, and holes are made on the other for levers used to screw the pile into the ground. The lower conical end of the pipe is hermetically sealed, and the blades are attached to it. The delivery set includes heads for fastening foundation beams (grillage). Surfaces are coated with anti-corrosion compounds.

The use of screw piles provides the following advantages compared to columnar and strip foundations:

• Reducing the cost of foundations up to 30%
• Reducing construction time to two days
• Walls can be erected immediately after tying the piles (in the case of using concrete foundations, you must wait a month until the concrete completely hardens)
• Possibility of construction on soft soils with high groundwater levels, in areas with difficult terrain
• When screwing in piles, the soil is not loosened, but compressed, which increases its load-bearing capacity, while due to the large surface area of ​​the blades, the pressure on the ground is reduced and resistance to the influence of frost heaving forces is increased
• No excavation work

Disadvantages include:

• Susceptibility of metal to corrosion when the protective layer is destroyed
• The need for thorough floor insulation
• Difficulties encountered during basement construction
• Impossibility of use on rocky and rocky soils

Screw piles have the following characteristics:

• Diameter - 56 - 325 mm
• Length - 1.5 - 9 m
• Blade diameter - 250 - 800 mm
• Pipe wall thickness - 3 - 12 mm
• Service life - from 60 years

For foundations for frame houses, piles with a diameter of 108 mm are often used, having the following characteristics:

• Length - 2.5 m
• Wall thickness - 4 mm
• Blade diameter - 30 cm

With a sufficient load capacity of up to (10 tons), they, unlike thicker piles, can be screwed into the ground manually. Installation of one pile takes 20 - 35 minutes. If necessary, pipes are extended using couplings secured by welding.

Screw piles can be installed on all types of soils, with the exception of rocky ones. In this case, you should choose a different foundation for a frame house. For example, ribbon or columnar.

Construction of foundations from screw piles

The installation scheme of piles, their depth and diameter must be indicated in the construction project of a frame house.

When designing the foundation, take into account:

• Building weight, snow and wind loads
• Results of engineering-geological surveys (groundwater level, soil characteristics)
• Soil freezing depth
• Terrain

Piles are installed:

• In the corners of the house
• At the junction of internal walls and external
• Under external and internal walls in increments of 1.5 - 3 meters

The piles are screwed in to solid ground, but not less than to the depth of soil freezing. To do this, markings are made and small pits are dug in the places where the piles are installed. A pile is installed vertically in the pit (deviation up to 5 degrees is allowed). A crowbar is inserted into the technological holes and two levers made of metal pipes 4 meters long are placed on it.

A minimum of three people are required to complete the work. Two of them walk in a circle, rotating the pipe using levers, the third controls verticality at a level attached to the pile with magnetic grips.

After screwing the piles to the designed depth, their upper part is cut off with a grinder at the mark of the top of the foundation. The cavity of the pipes is filled with concrete, which is compacted. This increases the load-bearing capacity of the structure and the resistance of the internal surfaces of the pipes to corrosion.

The last stage is the installation of a grillage. Wooden or metal beams are laid on the pile heads and bolted to them. Two layers of roofing felt waterproofing are laid between the beams and the caps. For frame houses, it is advisable to use wooden beams 150x150 mm. Its cross-section is determined by the thickness of the insulation layer laid in the walls.

The timber must be dry; before installation it is impregnated with antiseptic compounds. High-quality timber is not always available for sale, so it is often made from three edged boards 150 mm wide and 50 mm thick, knocked together. If the boards are knocked down staggered, you can make a beam of any length.

Many future owners do not turn to construction companies to build a frame house, but build it on their own. But for this you need to know the structure of a frame house.

One of the final stages of construction is the cladding of a frame house; a popular option is the use of siding or wood panels.