Shallow strip foundation for a frame house

The correct choice of the foundation of a house determines the durability of the structure. The foundation of a house is necessary to distribute the load and pressure of the walls over the ground surface. It also prevents the destruction of the house and the formation of cracks. Which foundation is better for a frame house - slab, pile or strip? And why will a structure without a foundation be short-lived?

Strip foundation for a frame house.

Strip foundation for a frame house.
Nowadays, frame houses are becoming increasingly popular. They are lightweight, which makes it possible to use any type of foundation. But most often they use a strip foundation for a frame house. This base has the appearance of a straight strip without joints or seams and is applicable on medium and high degrees of heaving soils; it will enable the building to stand firmly even on the most moving and subsiding soils, which makes it the most optimal option.

The strip base is erected in several directions - Finnish or Canadian technology. Some owners successfully achieve knowledge in this area and easily get to work on their own.

However, scrupulousness should be shown here, since mistakes during its construction are fraught with serious consequences.

Strip foundation for a frame house.

Calculation of a strip foundation for a frame house

Calculation of the foundation for a frame house begins with the calculation of the maximum loads on the foundation of the house. These loads include:

House weight;
Weight of the active part of the house;
Foundation weight;
Snow load;
Wind load.

The weight of a house consists of the weight of wall materials, the weight of the floors and the weight of the roof. If there are ready-made projects for country houses, then this data can be obtained from the project. Otherwise, you can use the average values of the specific gravity of frame house structures from reference tables on the Internet or special reference books. So for a frame house, the wall of which does not exceed 140-150 mm, the specific gravity of a square meter of wall is in the range of 30-50 kg/m2. In the same way, you can obtain data on the weight of the basement, attic floor and roof.

The weight of the active part of the house includes the weight of plumbing fixtures, boilers, stoves, fireplaces, household appliances and the weight of people. It is difficult to accurately determine the active part of the house, as is the weight of the foundation. The weight of the foundation, or rather its depth and width of the tape, depends on the soil and the total load on the foundation, so it is clarified after geological studies of the soil and determination of the total load on the foundation.

Snow and wind loads are determined from reference tables on average annual precipitation and the speed of prevailing winds in a given area. For the central part of Russia, the snow load is 170-200 kg/m2.

To determine the size and weight of the foundation, it is necessary to calculate the bearing capacity of the soil under the foundation of the house. This calculation will be carried out by specialized geological engineering companies, which will determine the composition of the soil, the level and direction of groundwater and give recommendations on the depth of laying the selected type of foundation. Such companies can obtain data from archives or drill on the site to determine the composition of the soil and the calculated soil resistance.

The calculated soil resistance can also be determined according to SNiP 2.02.01-83.

The calculation of the foundation for a frame house is carried out according to the formula, provided that the laying depth does not exceed 2 m:

S>Yn*F/Yc*Ro

S – supporting area of the foundation in m;
F – prefabricated load on the foundation in t;
Ro - shows the bearing capacity of the foundation for a given soil and is measured in kg/cm2;
Yn – safety factor of the foundation, assumed to be 1.2;
Yc is the coefficient of interaction between the foundation and the soil, determined for each type of soil.

Types of foundation.

The strip foundation can be built in several types:

Monolithic - constructed immediately on the construction site;
Prefabricated - consists of pillows and blocks made in production and assembled at a construction site;

Do-it-yourself strip foundation for a frame house.
Based on the type of burial, the base is divided into:

To choose the most suitable type for a frame house, you should pay attention to the shallow monolithic type. This structure is buried 0.5 meters and distributed along the entire length of the load-bearing walls. Rising and falling along with the soil during the season, it protects the building elements from deformation.

Before starting the activity, you should calculate all the nuances of the foundation:

Carry out geological surveys - this action depends on the financial capabilities of the owner; a group of professionals is hired or the determination is carried out independently. In the second case, to identify the type of soil, a trench up to 1.5 m deep is required;
Coordinate the construction plan with the BTI;
Check the project for the presence of a basement;
Determine the size of the house and main elements, calculate the load on the room;
Determine the presence of groundwater and the level of soil freezing.

For construction, gravel or coarse sandy soil will be most suitable; fine sandy soil has practically no good properties, and clayey soil leads to displacement.

Important: when calculating and deciding on the type of foundation, you should understand one detail - the service life of the building depends on the quality and durability of the foundation.

Do-it-yourself strip foundation for a frame house.

Types of strip foundations

Construction of a frame house

Strip foundations are divided into types according to their design:

monolithic - this type is installed directly on the construction site;
prefabricated - this foundation includes foundation pads and blocks manufactured at the factory and installed at the construction site;

Based on depth, strip foundations are divided into:

shallow;
buried.

For the construction of a frame building, a shallow monolithic one is more suitable. It has the form of a base that runs along the entire length of the load-bearing walls and is buried no more than half a meter. In winter and spring, this foundation, together with the soil, rises upward, and then returns to its original position. In this regard, there is no deformation of the main structural elements of the building.

Preparation and construction.

To carry out work on arranging this product, you need to stock up on:

Tools for strip foundations.

Reinforcing bars;
Sand;
Flexible metal wire;
Crushed stone of different calibers;
Several types of cement;
Waterproofing;
Pliers;
Saw;
Construction vibrator;
With a shovel.

Next, to make a foundation for a frame house with your own hands , you need to carry out work in accordance with these stages of work:

Site preparation: it is necessary to clear the approximate building site of stumps, grass, turf and other objects that may interfere with the construction of the foundation or ultimately destroy it.
Marking - before starting the process, calculate the dimensions of the base, then clearly determine the location of its construction and mark out this area using pegs and rope. During operation, even angles are determined using a laser meter. Start the process from the lowest angle. It is also important that during marking you should use durable colored cords so as not to turn a quick process into a lengthy task.
Digging a trench - after the previous event, a foundation is dug along the marking lines 0.5 m deep and 4 m wider than the designated landmark; when performing this work, everything should be measured with a level and plumb line in order to avoid mistakes, thereby complicating future stages of work.
Forming a cushion - a sand blank is placed on the bottom, which is poured abundantly with water and compacted, followed by a layer of crushed stone.
Formwork installation:

Waterproofing - it is formed on the sides of the trench surface, for example, roofing felt is used, but this material is not without its drawbacks. But new technological developments offer Penetron, which is added directly to the concrete mixture and makes the base impenetrable;
Formation of formwork - boards 5 cm thick and no more than 150 cm wide are laid vertically along the upper edge of the waterproofing; there should be no gaps between them. This installation should rise 30 cm above the ground;
Reinforcement - reinforcement with a diameter of 10 - 16 cm, tied with wire, is placed inside the formwork to maintain the flexibility of the reinforcement. The reinforcement should be laid 5 cm below the top of the formwork in order to completely hide it under the concrete;
Concreting - in the end, everything is filled with a mixture of concrete, sand, gravel and water, its consistency resembles thick sour cream; plasticizers can be added for strength. This mixture can be purchased ready-made or made independently using a concrete mixer and vibrator.

The following arguments support the second option:

Faster process;
The qualities of cold seams are preserved; as a result, moisture will not circulate through them and destroy the base;
With all this, there is practically no difference in financial matters.

After complete completion, the base is covered with waterproof material to avoid cracks. It will harden up to 2 days, and it will take several weeks to develop strength.

When performing formwork, you should use smooth, strong panels so that it is beautiful and neat.
Nails should be driven into the boards from the inside out - you will feel the correctness of this process when removing the boards.
At the stage of formwork formation, it is necessary to take care of the holes for pipes and cables, so as not to hollow them out in the future, thereby destroying the integrity of the monolith.

Do-it-yourself strip foundation for a frame house.

Strip foundation device

There are the following stages of construction of a strip foundation:

Foundation marking

When all the materials and tools are prepared, it is necessary to mark the building in relation to the walls and facades. You need to clearly know where the foundation will stand. You also need to calculate the dimensions of the strip foundation for a frame house. After the calculations, the foundation is marked. For marking, use pegs and a rope stretched between them. Stretch the next row of ropes 10 cm more than the width of the walls. It is also necessary to make the corners straight. To do this, use a laser meter, or simply measure and compare the diagonals.

After this, according to the markings, they dig a trench half a meter deep. Sand preparation is laid at the bottom of the trench and filled with water.

Construction of a strip foundation.

The next stage is the installation of formwork:

Foundation waterproofing. First, waterproofing is laid on the sides of the trench surface. This may be a layer of roofing felt. But the disadvantage of roofing felt is that after a couple of years it will begin to peel off from the surface and the waterproofing will have to be repeated. Keeping pace with new technologies, Penetron can be used as a waterproofing material, which is added directly to the concrete mixture. It will make the foundation an impenetrable structure.
Formwork installation.
Edged boards 5 cm thick are laid vertically on top of the waterproofing. It is recommended to knock down boards from the inside, and nails are directed from the outside. There should be no gaps between the boards. Most often, boards made from coniferous trees are used for formwork. Boards made of aspen and alder are allowed. They should not be damp and no more than 150 cm wide. The boards should be 30 cm above ground level. Reinforcement of a strip foundation for a frame house
Reinforcement of strip foundation. Reinforcement with a diameter of 10 to 16 mm is placed in the middle of the formwork, pre-cleaning it of rust and dirt. Before installing reinforcement, it is necessary to carefully inspect the formwork and eliminate all defects. The reinforcement is tied with wire or welded. Welding has the disadvantages that with this method of connecting reinforcement, the flexibility of the reinforcement decreases. You can knit the wire with pliers or use an automatic gun. About 5 cm of the top should be left without reinforcement, so that subsequently all the reinforcement is covered with concrete mixture.
Concreting. After this, the formwork is filled with concrete. Concrete is made from M500 cement, sand in a ratio of 1:3, gravel and water. Sometimes plasticizers are also added. They provide strength to the foundation. The consistency of the concrete mixture should be neither liquid nor dry. It looks like thick sour cream.

You can either buy the concrete mixture ready-made or make it yourself in a concrete mixer. First, bulk materials are poured in, and then water is added. The concrete mixture is poured into the formwork to the specified level and leveled. The foundation is poured in several passes, since the amount of mixture is very large. The gaps between approaches should be no more than a day. You need to monitor how the concrete mixture behaves.

A vibrator is used to compact concrete. It removes remaining bubbles from the inside so that pores do not form in the concrete. The vibrator reduces the adhesion of the concrete and the concrete mixture is well compacted. When the foundation dries, it is covered with waterproof material. This prevents cracks from forming.

It will take about two days for the concrete mixture to harden. But the foundation gains strength within a few weeks. If you decide to build a bathhouse in parallel with the house, then after pouring the foundation for the house, you should begin constructing a strip foundation for the frame bathhouse.

Pros and cons of strip foundations.

The positive side of the construction of a strip plinth is:

Optimal amount of money spent;
Reliability - it is one whole, impenetrable;
Over the years, this has been a refined construction technology known to most builders;
This is a ready-made impenetrable base relative to, say, a pile base.

The need to be scrupulous in formwork formation;
Difficulty working on sloped areas;
It is problematic to carry out the process alone;
Access is required for heavy equipment - mixers and other construction vehicles.

Making this type of plinth for a panel house yourself is not a difficult task at all, only its arrangement requires maximum effort and knowledge, so that it subsequently serves for a long time and extends the life of the house.

Advantages and disadvantages

The advantages of shallow tape include::

Reliability and strength of the base.
Reduced volumes of labor costs, in particular excavation work.
The consumption of building materials is reduced by almost three times.
Possibility of doing all the work yourself.

There are also disadvantages:

There are restrictions on the weight and number of floors of the building.
It is necessary to equip a drainage system, especially when building on heaving soils.
Before construction, it is necessary to conduct a thorough examination of the geological situation on the site.

Dependence on the type of soil is characteristic of almost all types of foundations, so the only serious disadvantages include the inability to support heavy and large buildings.

Selection of design, determination of dimensions.

Of all the strip foundation , the following modifications are optimal for a frame house

shallow MZLF – depth 0.4 – 1 m, two-layer reinforcement
monolithic belt - laid on the surface, the fertile layer underneath is replaced with sand bedding
not recessed - also rests on a cushion made of non-metallic materials, has a greater height than the belt

Any option must be protected from heaving forces by drainage, insulation of the blind area, side edges, and replacement of heaving soil with crushed stone or sand. On slopes, MZLF is not recommended due to high shear forces. When building on dusty sands or embankments, the lower part of the MZLF should be widened with a slab.

Tape depth.

The minimum budget for a strip foundation is observed at a depth of 2.5 m. If the bearing layers are located below this mark, pile foundations should be considered or the beam should be strengthened with them. If the calculated soil resistance at a depth of 0.4 - 0.7 m ensures the normal bearing capacity of the MZLF, other problems (swelling, high level of groundwater level) are easily solved by appropriate technologies.

Calculate the strip foundation for a frame house.

The main advantage of a monolithic belt, MZLF, non-buried structure is the minimum of excavation work. An increase in the construction budget (purchase, installation of insulation, backfilling with crushed stone, sand, drainage pipes) is justified by reducing heaving forces and increasing the time between repairs.

Width, height of the structure.

A frame house rests on a reinforced concrete beam with a bottom strapping beam, the width of which rarely exceeds 15 cm. However, the minimum recommended size for a cottage is 30 - 40 cm, which guarantees a 2 - 3-fold increase in load-bearing capacity.

The height of the monolithic structure should be greater than the width (2 - 4 times). Which for the above size is 0.6 - 1.2 m. Taking into account the depth of location, this will provide a normal basement part, allowing you to arrange both ceilings on beams and floors on the ground.

Strip foundation for a frame house calculation.

In the first case, the base part will have to be equipped with ventilation ducts with an area of 1/400 of the size of the entire base. In the second option, there is no need to leave technological holes.

Calculation example

Frame house measuring 7 x 7 m. The length of the tape is 30 m, taking into account the internal walls of the house. The prefabricated load on the foundation was 110 tons. The soil under the foundation is loam, for which Ro = 3.6 kg/cm2. Yc for this soil is 1.1. Taking into account the characteristics of the soil, the foundation depth is 1.8 m.

The supporting area corresponding to the bearing capacity of the foundation must satisfy the following inequality:

S > 1.2* 110000/ 1.1* 3.6 or,

S > 33,333 cm2 = 3.33 m2

Determine the width of the tape:

3.33/30 = 11 cm.

Since the width of the foundation cannot be less than the thickness of the walls, and the thickness of the walls is 15 cm, we take the width of the tape to be 18 cm, against the calculated one, and S will then be 30 * 0.18 = 5.4 m2

Taking into account the soil resistance Ro, we determine the bearing capacity of this foundation

54000 * 3.6 = 194 tons with a maximum load on the foundation of 110 tons.

Construction technology.

To build a strip foundation , it is necessary to mark out the building site, remove the soil, install formwork, and lay concrete after installing the reinforcement frame. In this case, technologies are used to reduce heaving forces harmful to reinforced concrete.

First, drains are laid (the level of the base of the tape), then the soil under it is replaced with crushed stone and sand. Then the blind area is insulated, allowing the geothermal heat of the subsoil to be retained under the building.

Waterproofing all concrete surfaces dramatically increases the service life of the cottage's load-bearing frame elements operating underground.

Full-scale axle offset.

Since to install the foundation it is necessary to make trenches, transfer the drawing from the project to the building site, marking is necessary. The removal of the wall axes occurs as follows:

object reference - the corner of the home should be 5 m from the center of the street, the driveway, the border of the site - 3 m, it is worth taking into account the location of the septic tank, water intake source, communication wells (3 - 10 m, respectively)
cast-offs - used instead of pegs, consist of two vertical bars, pointed at the bottom, with a horizontal board between them (60 - 80 cm), mounted 1 - 1.5 m from the edge of the trenches

Laying out the foundation for a frame house.
3 strings/cords are pulled along the cast-offs (the side edges of the tape + the axis of the wall), which can be removed during excavation work and installed back after completion. A frame house must have identical diagonals, so the axes are laid out at right angles to each other using the triangle method with a hypotenuse of 5 m, legs of 4 m, 3 m. SP standards allow an error of 1 cm.

Any foundation requires drainage, constructed using external underground sewerage technology:

production of trenches - they run along the perimeter of the building at the depth of the base of the MZLF, have a cross-section of 50 x 50 cm, a general slope towards the underground tank, where the stacks will be collected by gravity (4 - 7 degrees)
underlying layer - 10 cm of compacted crushed stone 5/20 mm over geotextile (the edges need to be extended onto the sides of the trench to cover the entire structure from above with the material)
installation of wells - vertical pipes with a plugged bottom 30 - 80 cm in diameter in the corners of the cottage to clear clogged areas from the surface of the ground
laying drains - pieces of perforated corrugated pipe (two-layer winding with dornite/geotextile), interrupted inside the wells

Connection to the foundation.
After that, all that remains is to fill the trenches on the sides and top (10 cm) with crushed stone so that the frame house receives reliable protection against swelling.

Bedding, concrete.

To prevent cracking of the foundation from swelling and leveling the bottom of the trench, 40–80 cm of non-metallic material, compacted in layers (every 10 cm using a vibrating plate), is required. There are several schemes for inert cushion (depending on the geological conditions of the building):

crushed stone to the full depth - at high groundwater level
sand 40 – 60 cm – with low groundwater level reduces the construction budget
crushed stone + sand – equal thickness with low design soil resistance
sand + crushed stone - with a possible seasonal rise in groundwater level

Laying out the foundation for a frame house.
The following problems are solved by footing:

no maintenance of cement laitance when pouring
protection of waterproofing carpet from punctures by crushed stone
reduction of the lower protective layer for reinforcement

Foundation footing for a frame house.
The footing is a 5 - 7 cm screed made from a mixture of grade B7.5 (lean concrete). It is poured into formwork, the width exceeds the size of the tape by 20 - 40 cm for reliable support.

Plantar waterproofing.

A membrane, 0.15 mm polyethylene film is laid on the screed, or roll waterproofing (TechnoNIKOL, Bikrost) is fused. It is necessary to protect reinforced concrete structures from soil moisture and pressure water.

A frame house consists almost entirely of lumber, which absorbs any moisture. Therefore, reinforced concrete surfaces must be waterproofed later.

Depending on the depth of the tape, formwork of different designs can be used:

plank, plywood panels - at a depth of 40 - 70 cm
L-shaped polystyrene modules - for non-buried strips, belts

Width of strip foundation for a frame house.
In order for the house to have a stable spatial geometry, heaving forces are eliminated by insulating the outer surface of the MZLF and blind areas. Thermal insulation can be placed in the formwork (pressed against the outer panel from the inside) or this material can be used to cover the side of the tape after stripping.

To maintain the geometry of the foundation, it is recommended to use a board with a thickness of 4 cm (guaranteed no deflection when laying concrete). The spacing of the jibs on the outside of the boards is 30–50 cm, the lintels in the upper part are similar.

Reinforcement frame.

Concrete structures work exclusively under compression from the forces that the house . snow/wind, operational loads. Therefore, the foundation is reinforced with two belts of longitudinal rods, which absorb tensile forces during possible heaving of the soil. The main requirements are:

minimum percentage of reinforcement – 0.1 – 0.3%
selection of reinforcement section - by calculation depending on bending moments
providing a protective layer – 2 – 7 cm
rational schemes for tying connections - U-shaped clamps, rods bent at right angles
overlap, connection of rods - at least 40 - 60 cm, spacing of joints of adjacent rows 60 - 80 cm

Resistance of a strip foundation for a frame house reinforcement.
In individual construction, taking into account the minimum weight of “frameworks,” A400 reinforcement (longitudinal rods) with a periodic section of 8–16 mm is used. Clamps, transverse and vertical jumpers are made from smooth A240 reinforcement. They are bent exclusively in a cold way; heating is strictly prohibited. The reinforcement method looks like:

production of frames - for straight sections, longitudinal rods (usually 2 upper + 2 lower) are tied with rectangular clamps (step 30 - 60 cm)
laying - frames are placed on concrete or plastic spacers inside the tape
couplings - straight frames are connected in corners, T-shaped junctions with U-shaped clamps or L-shaped anchors

Lateral protection of the reinforcement is provided by plastic elements placed on longitudinal bars or clamps.

Concreting.

To ensure that the house has the maximum possible resource, concrete grades B15 - B25 are used, laid in layers (60 cm maximum) for subsequent compaction with deep vibrator attachments in one direction. If, at the stage of preparing the mixture, the penetrating composition Admix is introduced into it, the concrete will receive water-repellent properties by default. You won't have to waterproof it later. The mixture can be added to a mixer ordered by the developer at the construction site.

Shallow strip foundation for a frame house.

With sufficient compaction (5 - 10 seconds), the concrete almost instantly restores a flat surface when the vibrator attachment is removed. Cement laitance appears on the surface, the formation of bubbles stops, and the large filler is completely hidden inside the structure.

Waterproofing.

To protect the foundation from getting wet, which leads to cracks opening in winter, all edges of the MZLF are waterproofed using the following technology:

primer – produced by primers to increase the adhesion of the surface to waterproofing materials
coating - epoxy, bitumen mastics in two layers to form a film with a 15-20 year lifespan
pasting - hydroglass insulation, TechnoNIKOL, Bikrost, other rolled materials in two layers
volumetric waterproofing - penetrating compounds are used, after entering into a chemical reaction with cement, the structure of concrete is changed to the entire depth

Waterproofing the foundation for a frame house.
The first three methods are usually used in combination, but are still inferior to volumetric waterproofing, which has an unlimited resource.

Thermal insulation.

In combination with measures already taken to prevent heaving, thermal insulation of the blind area and outer edges allows you to completely protect the frame house from heaving forces. The walls of the MZLF are covered with a 5 cm layer of extruded XPS polystyrene foam. PSB-S polystyrene sheets of similar thickness are laid under the blind area at a depth of 30–40 cm.

Thermal insulation of a strip foundation for a frame house.

If the technologies specified in this manual are followed, the house is guaranteed to last three to four generations of owners.
Advice from professionals will help you avoid mistakes, ensure comfortable operation, and a long period between repairs of the building.

Calculation of house weight

So, you need to calculate the approximate weight of the house. For this purpose, there are reference data with average values of the specific weight of house structures: walls, floors, roofs.

Specific gravity of 1 m2 of wall

Frame walls 150 mm thick with insulation	30-50 kg/m2
Walls made of logs and beams	70-100 kg/m2
Brick walls 150 mm thick	200-270 kg/m2
Reinforced concrete 150 mm thick	300-350 kg/m2

Specific gravity of 1 m2 of floors

Attic on wooden beams with insulation, density up to 200 kg/m3	70-100 kg/m2
Attic on wooden beams with insulation, density up to 500 kg/m3	150-200 kg/m2
Basement on wooden beams with insulation, density up to 200 kg/m3	100-150 kg/m2
Basement on wooden beams with insulation, density up to 500 kg/m3	200-300 kg/m2
Reinforced concrete	500 kg/m2

Specific gravity of 1 m2 of roofing

Sheet steel roofing	20-30 kg/m2
Ruberoid coating	30-50 kg/m2
Slate roofing	40-50 kg/m2
Roofing made of pottery tiles	60-80 kg/m2

Based on these tables, you can roughly calculate the weight of the house. Let it be planned to build a two-story house measuring 6 by 6 with one internal wall with a floor height of 2.5 m. Then the length of the external walls of one floor will be (6 + 6) x 2 = 24 m, plus one internal wall another 6 m long, for a total of 30 m. The total length of all walls on two floors is 30 m x 2 = 60 m. Then the area of all walls will be: S walls = 60 m x 2.5 m = 150 m2. The area of the basement floor will be 6 m x 6 m = 36 m2. The attic floor will have the same area. The roof always protrudes somewhat beyond the walls of the house (let’s say 50 cm on each side), so we calculate the roof area as 7 m x 7 m = 49 m2.

Now, using the average data from the tables above, you can make a rough calculation of the total load on the foundation. In this case, we will take the largest specific gravities in order to count with a margin. For comparison, the calculation was made for three house options: - a frame house with wooden floors with insulation with a density of up to 200 kg/m3 and a roof made of Ondulin type sheet material; — a brick house with wooden floors with insulation with a density of up to 200 kg/m3 and a roof made of sheet steel; - a reinforced concrete house with reinforced concrete floors and a roof made of pottery tiles.

In addition to the permanent load created by the weight of the house, there are temporary loads from wind and snow cover. The average snow cover weight is given in the table:

For the south of Russia	50-100 kg/m2
For central Russia	150-200 kg/m2
For the north of Russia	more than 200 kg/m2

With a roof area of 49 m2 for central Russia, the load from snow cover will be 49 m2 x 100 kg/m2 = 4900 kg. We add it to the total load on the foundation.

House	Wall weight, kg	Basement ceiling, kg	Attic floor, kg	Roof weight, kg	Snow cover, kg	Total, kg
Frame	7500	5400	3600	1470	4900	22870
Brick	40500	5400	3600	1470	4900	55870
Reinforced concrete	52500	18000	18000	3920	4900	97320

DIY foundation for a frame house. Types of foundations, calculation, construction.

Building a house often replaces buying an apartment. These types of housing are almost the same in cost, but in the case of building a frame cottage, the budget can be saved significantly. All work on the construction of the structure - from the base to the roof - can be done independently, knowing the technology. Building a foundation for a frame house with your own hands is not difficult even for a person who has not previously dealt with such matters. In this article we will look at the types, methods of construction and the advisability of using one or another type of foundation for each case.

Construction of the foundation

To prepare the concrete solution, in any case, you will need an electric concrete mixer. Some “craftsmen” use a construction mixer for these purposes. If a person is ready to spend a couple of weeks preparing the solution in this way, go ahead, but a concrete mixer is still better.

If the unit has a large throughput, then the optimal proportion for mixing the concrete solution will consist of the following components:

25 kilograms of cement (almost always this is exactly half a bag);
75 kilograms of sand;
125 kilograms of gravel (the smaller the gravel fraction, the better);
12-13 liters of water (this amount depends on the moisture content of the sand and dry cement, so everything will need to be determined by eye, 13 liters is an average figure).

Installation diagram of a strip foundation for a frame house

Immediately after preparing the next portion of the concrete mixture, it must be poured into the trench and lightly compacted. This must be repeated until the base of the house in the formwork reaches the required level. But the concrete mixture can dry out in different ways.

If the air humidity level is too high, then the whole process may take two weeks. If the weather is sunny and dry, the concrete will harden much faster. If it rains, then the base (formwork) that has not yet hardened must be covered with plastic film, otherwise it can dry out endlessly, figuratively speaking.

What is a frame cottage?

The technology for building modern lightweight houses came to us from America. Another name for them is Canadian. In these countries, most suburban buildings are made using this technology, which is fully justified: the home is warm, reliable, lasts for many years, is cheap, and can be built quickly. In Russia, such objects appeared relatively recently (about 15 years ago), but are actively gaining popularity due to their qualities.

The technology for constructing frame and frame-panel houses is as follows:

A vertical frame of walls made of wooden beams along the entire perimeter is installed on the constructed foundation.
Fill the space between guide sandwich panels or panels made of OSB and insulation.
The walls are sheathed with facade and finishing materials.

Frame house on a strip foundation.
Thus, the construction of the walls is very light. Which foundation is better for a frame house? Definitely not powerful, it is not necessary. This allows you to save not only construction time, but also money on materials and labor.

Criteria for choosing a foundation for a panel house

If you choose a foundation for a house made of frame panels, you should note that the following types may be suitable for these purposes:

tape;
slab;
columnar;
pile

The simplest option for a relatively light frame wooden house is a columnar foundation. It consists of several wooden pillars of the same thickness and height driven into the ground. This is the basis of a columnar foundation (hence its name).

But there is an important nuance: despite all its cheapness and simplicity, such a foundation can be used for a prefabricated panel house only on strong (vegetative or gravelly soils).

If the building itself is located on sandy or peat soil, or loam, then a columnar foundation will no longer be suitable: it will simply be unstable and even light frame-panel houses will experience serious shrinkage after the start of operation. Pile foundations for frame-panel houses are rarely used.

Scheme of a frame-panel house with a foundation

They are used either where the soil is extremely strong (rock soils, for example), or where the soil on top is loose (sandy) and it is necessary for the foundation to stand on a more durable layer. It must be said right away that a pile foundation is the most expensive, but also the most reliable. Strip foundations are the most common, if we consider only “frameworks”.

And there is nothing supernatural about this: such foundations can easily support even a two-story frame house, while shrinkage of the structure during initial operation will be minimal. Therefore, it is worth talking about the strip foundation in more detail.

Scheme of columnar monolithic and prefabricated foundations

A columnar foundation cannot be used for frame houses only if they are built on sandy soils.

Is there a single solution?

There is no exact answer to the question of which foundation is best for a frame house. There are many types of lightweight structures, the use of which is optimal in a particular case. The basis can be:

Different materials are used for the foundation:

Thus, there may be several options for constructing a foundation for a house. The choice is influenced by:

house size;
number of storeys;
soil freezing depth;
availability of groundwater;
soil type: mobile, wet, viscous, hard;
presence/absence of a basement.

The best foundation for a frame house is one that takes into account all the nuances of construction and geological conditions. A properly selected base will last a long time and help save time and money.

Geological surveys

Not only the calculation of the foundation is important for the construction of a stable frame house, but also the characteristics of the soil and geological features. Specialists designing structures carry out complex geological surveys - drilling and studying the material in the laboratory.

If the frame building will be erected independently, then a visual examination is often sufficient. For this purpose, drilling is carried out to a depth below the base of the foundation by about 50-100 cm. This will help determine the type of soil and exclude the presence of water-saturated layers . It is recommended to do this check in several places, since unstable soil may be nearby, within the building.

Useful: We are building a pile foundation for a frame house

We determine the characteristics of the base.

The first step is to determine the type of soil at the proposed construction site. The best way to do this is to order geotechnical surveys. Experts will determine:

the exact type of soil and its characteristics;
availability of groundwater and its nature;
They will draw up a site plan taking into account elevation changes and terrain features.

True, such pleasure is expensive and takes a lot of time. Another option is to find a neighbor in the area who has already applied for such a service and has the results of an examination of his territory. As a rule, soil characteristics in one area have the same properties.

If there is no neighbor with a conclusion, you can try to determine the type of soil yourself. To do this, follow these steps:

Dig a hole to the frost depth in the region. You can find it out using the map.

Soil freezing depth.

Analyze a section of soil along the side wall of the pit.

Rocky soils consist of rocky and gravel bases. They are strong enough, able to withstand any weight, and do not retain water (provided they do not contain a large amount of clay).
Coarse sands and cartilaginous soils are also characterized by a low degree of heaving and a strong foundation.
Fine sandy soils are not the best option for construction. They retain water, which solidifies in the upper layers and acts on the foundation by pushing and compressing. This property is called heaving.

Soil for a frame house.

Loams and clay are the most unfavorable type of soil. Their mobility and buoyancy depends on the height of groundwater. But even in their absence, there is often enough moisture from precipitation. In areas with such soils, large puddles form because water drains into the ground very slowly.

The type and depth of the foundation for a lightweight frame house depends on the geological conditions of the area.

Recessed strip foundation

This is a classic version of the foundation for a building made of brick or concrete. In frame construction they are used in the construction of houses with basements or ground floors.

The main condition for installing a recessed strip foundation is a constant low groundwater level. Even a slight and infrequent rise in underground moisture leads to leaks, dampening of the basement walls, and destruction of the finish.

The base of the base rests on the horizon of standard soil freezing. This excludes the action of frost heaving forces from below, but tangential forces and lateral pressure of the earth are present.

Therefore, a deep strip foundation for a frame house is calculated and implemented, observing all the necessary requirements.

We take into account the depth of freezing.

This aspect is relevant for soils subject to heaving. Rocks that do not retain water serve as a solid foundation in any season, unlike fine sandy and clay soils. If the latter are present, the depth of the foundation should be greater than the freezing value, then it will be able to firmly fix the building in one place and position. This is necessary to prevent uneven subsidence of the structure, which can lead to damage to the integrity of the house, its destruction or large investments in repairs.

It is also important to find out about the presence of groundwater. If they are present, you need to look for a way to deal with them or equip the structure in such a way that it is able to withstand a humid environment and conditions of severe heaving. The depth of soil freezing is not included in the calculations of a pile foundation.

Types of strip foundation

The main characteristics and scope of application of a strip foundation vary depending on the degree of its depth, construction technology and materials used.

According to the depth of the foundation

Shallow

For light structures of residential buildings, a shallow strip foundation is used (depth up to 70 cm). More massive buildings made of stone or brick, as well as the intention to build a full-fledged basement, will not allow you to save money and will require a buried foundation (the depth is calculated by the formula: soil freezing depth + 30 cm).

Recessed

A buried foundation, of course, is stronger and less susceptible to deformation due to soil heaving. However, it requires a large amount of materials and labor-intensive construction work.

The installation of a strip foundation of any type is best done in the warm season, since there is a need to dig a basin, and working with frozen soil is quite problematic.

Important! On deeply frozen soils and soils with severe frost heaving, this type of foundation is not recommended.

We decide on the design.

Based on the work done to determine the type of soil and the depth of its freezing, you can decide which foundation design for a frame house is optimal in a given location.

On clayey and fine sandy soils, a pile foundation is installed. It fixes the structure in durable layers below the groundwater level.
Shallow slab foundations work well on heavily heaving loams and silty rocks. They play the role of a “boat”, capable of staying afloat and holding the house in one plane over the entire area of the structure.
Rocky, coarse sandy, gristly soils themselves serve as a solid foundation, so they do not require a solid foundation - strip, shallow and columnar will be enough.

In the presence of groundwater, special types of waterproof concrete are chosen and additional waterproofing of the foundation walls is used. If the GWL is high, you should abandon the basement. In addition, it is advisable to install a drainage system throughout the area or directly next to the house: a trench is dug along the perimeter, through which excess liquid drains in a given direction.

We figured out the main stages. Next, we will consider in detail the principles of construction of different foundation designs and methods of their installation.

Construction technologies

The construction of a strip foundation begins with marking the construction site. Next, the soil is removed, formwork is installed, and concrete is poured into the reinforced frame.

Useful: We are building a columnar foundation for a frame house

At the initial stages, technologies are actively used that reduce the harmful effects of heaving forces. To do this, builders install drains (at the level of the base of the base). The soil layer under the drains is replaced with crushed stone or sand. Then the blind area is insulated. This is done in order to retain the heat received from the soil under the structure.

Waterproofing all concrete components of the foundation allows you to increase the service life of the entire structure.

Transferring axes

Installation of formwork begins with digging trenches. They are made in strict accordance with the project drawing. The trench line is drawn as a marking on the construction site. The removal of wall axes is carried out in the following way:

Object-based binding. The extreme corners of the building must be at least 5 m away from the street. From the driveway and the extreme point of the site - 3 m. It is also necessary to take into account the location of communications, a well, a water intake and a septic tank.
Instead of stakes, cast-offs are used. They are made of two beams with a lower pointed part. A board 0.6-0.8 m long is mounted between them. Such structures are installed along the edges of the trenches.

3 cords (strings) are pulled onto the cast-offs. The cords are pulled onto the side faces and wall axes. The strings can be removed before digging begins and reinstalled after completion. A frame house must have equal diagonals.

For this reason, the axes are laid at right angles (relative to each other). The result is a triangle with a hypotenuse of 5 m and legs of 3 and 4 m. Modern building standards allow design deviations of 1 cm.

Drainage system

A strip foundation for a frame house requires drainage. It is performed using the same technology as external underground sewerage.

At the first stage, trenches are dug. They should run along the entire perimeter of the future building. The depth of the trenches should be equal to the depth of the base. Section – 0.5*0.5 m. It is very important that the section has a slope of 4-7 degrees. This will ensure gravity.
Next, an underlying layer is installed. Geotextiles are laid at the bottom of the trench, and crushed stone is poured on top of it. In this case, the edges of the material must be released onto the side edges of the trench. This is done with the aim of subsequently covering the entire structure with material.
After the underlying layer, wells are installed. They are vertical pipes with a plugged bottom. Such improvised wells are installed along the edges of the future house.
At the last stage, drains are laid. They are a perforated corrugated pipe. Drains are installed inside wells.

The drainage system needs protection against swelling . This is achieved by pouring crushed stone into trenches.

Footing and bedding

Heaving can lead to cracks in the foundation. To avoid this, it is necessary to level the bottom of the trench by backfilling with non-metallic materials. A layer 40 cm high is created. It is leveled layer by layer using vibrating plates. There are several ways to create an inert pad. Each method is suitable for certain geological conditions.

Crushed stone completely filling the trench. This option is used when the groundwater level is high.
A layer of sand of 40 cm. This is a budget method. It is used at low groundwater level.
Crushed stone and sand. This scheme is used in regions with low soil resistance.

The following problems can be solved with the help of concrete:

Reducing the consumption of cement mortar when pouring the tape.
Ensuring protection of the waterproofing layer from puncture by crushed stone.

The footing is a screed of 5-7 cm . It is made from so-called “lean concrete” grade B7.5 and poured into formwork. The width should exceed the size of the foundation strip by an average of 30 cm. This increases the reliability of support.

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Sole waterproofing

The screed is covered with a membrane, which is a special film material. Using this material you can protect the foundation and the entire frame house from moisture and water.

Formwork

The choice of formwork is influenced by the depth of the strip foundation. The following types of formwork are distinguished:

Wooden or plywood structures. They are used if the depth does not exceed 70 cm.
Polystyrene L-shaped modules. This formwork is used for a monolithic belt or a shallow base.

To ensure stable spatial geometry of the structure, it is necessary to eliminate heaving forces. This can be done by insulating the upper parts of a shallow base.

Thermal insulation material is placed directly into the formwork (pressed against the outer part of the structure). You can also cover the sides of the tape with insulation after removing the formwork. You can maintain the geometry of the foundation using boards 5 cm thick.

Rebar frame

The foundation is constantly under load at home. For this reason, the strip foundation for a frame house is reinforced in two longitudinal belts. They take on the tensile load in case of soil swelling.

Basic requirements for the frame:

The minimum allowable percentage of reinforcement is 0.1%.
The cross-section of the reinforcement is selected based on calculations and features of the future structure.
The protective layer should be 2-8 cm.
Bandaging of mating elements is carried out with U-shaped clamps or rods bent at an angle of 90 degrees.

In the construction of private houses, reinforcement of the A400 brand is used, with a periodic cross-section (section frequency 8-16 mm). Vertical and horizontal jumpers and fastening clamps are made from A240 reinforcement. It is worth noting that such reinforcement is bent using the cold method; hot bending is strictly prohibited.

Concreting

The use of concrete grades B15-25 for a strip foundation increases the service life of a frame house. Concrete is poured in several layers. This allows subsequent compaction to be carried out using internal vibrators. If, at the stage of preparing the mixture, penetrating substances are added to it, the concrete will acquire water-repellent qualities. With high-quality compaction, the concrete immediately covers the surface, making it even.

Waterproofing

To protect against moisture, all edges of the foundation are waterproofed using the following technology:

Surface primer. It is done using primers. This increases the adhesion of the outer part to waterproof materials.
Coating. The structural elements are coated with bitumen or epoxy mastic. This coating guarantees protection of the base from exposure to water for 15-20 years.
Covering the foundation with water-repellent materials.
Volumetric waterproofing. Involves adding penetrating compounds to the cement mixture. This technique allows you to change the entire structure of concrete, making it insensitive to moisture.

The first three waterproofing options are most often used simultaneously. However, in all respects they are inferior to volumetric waterproofing.

Thermal insulation

Thermal insulation of a strip foundation allows you to protect a frame house from the effects of soil heaving. Most often, the foundation walls are covered with a layer of polystyrene foam (it must be at least 5 cm thick). Polystyrene sheets of the same width are placed under the blind area.

If you follow all the rules, the foundation will last at least 300 years.

Pile-grillage foundation.

This is a widespread type, universal in use. Since Russia is not rich in hard rocks, heaving soils of varying degrees of freezing predominate over most of the territory; pile foundations are used for the construction of buildings for various purposes and number of storeys. The pillars penetrate deep into the soil and are fixed with their lower ends in dense layers. Due to this, the structure resting on them is securely fixed relative to the ground surface.

Driving foundation piles for a frame house.

To build a pile foundation for a frame house with your own hands, you first need to calculate the number of pillars for the structure. To do this you need:

Look into the project, if there is one. If it is not there, see further.
Draw the perimeter of the future house on paper to scale. Mark the installation locations of the piles with dots (in all corners, where walls meet, along the perimeter in increments of 1.5-2 meters). Since a frame house is light in weight, reinforcement of the structure will most likely not be required, so a simple arrangement will suffice.
Count the number of marked points.

The next step will be to decide which piles to use: ready-made reinforced concrete or screw products from the factory or poured into ready-made wells on your own site.

The finished pillars are buried using a special installation. They are hammered to the required level in the designated places, then the remaining ends are cut off to the level. For a lightweight building, it is enough to buy piles with a minimum cross-section.
Screw metal supports are tightened with a special device.
If a decision is made to construct piles independently, then first wells are drilled, the bases of which must be made wider for stability. The depth depends on the geological conditions of the area. You need to get to solid ground. Then a waterproofing material is installed into the cavity, for example, a hollow pipe or twisted roofing felt. After this, the frame is laid and concrete is poured. It is optimal to use a solution of the M300-M400 brand. It would be good if it contains special additives that give the stone water-resistant properties.

The piles are installed, now you need to arrange a grillage. In the future, the wall frame will rest on it.

The grillage can be prefabricated or monolithic. The difference lies in the installation method:

The prefabricated one is mounted on reinforced concrete piles topped with a cap.
Monolithic is installed at the construction site: formwork is installed, if necessary, a cushion of ASG is laid at the bottom of the grillage, waterproofed with roofing felt and a finished frame is installed, which is connected to the reinforcement of the pile pillars. After this, the concrete mixture is poured.

The foundation is ready. It is worth noting that this design does not imply the presence of a basement.

Pile foundation

Installation in any season

At any time of the year you can install the foundation using special equipment

Low cost

Low cost due to simple installation, which you can do yourself

Installation on any ground

Particularly suitable for mountainous and marshy areas

Metal screw piles that can be used when constructing a pile foundation for a frame house can be of several types: with two blades welded at the bottom, with blades and a cast tip, multi-turn.

In addition, they can be without heads, with technological holes and with already welded heads in the form of flanges. They may also differ in the type and quality of the anti-corrosion coating, diameter, length, wall thickness, metal quality, and load-bearing capacity. When laying a foundation for a frame house with your own hands, most often, screw piles with a diameter of 89-108 mm and a length of 2.5-3 m are used.

Columnar foundation.

Optimal for flat terrain in relatively stable soils. Similar to pile, but less buried.

You can build a columnar foundation for a frame house with your own hands using the following technology:

Make markings on the plan. The supports are located in corners, wall intersections, and along the perimeter in increments of 2-3 meters. Next, these points are transferred to the site.
They dig holes for the pillars. If the foundation is made of asbestos pipes or monolithic pillars, the recesses are made with a motor drill rented for the day. Holes are dug under the stone pillars with a shovel. The size of the excavation is 60x80 cm, and the depth should be 20-30 cm below the soil freezing level.
Waterproofing for a monolithic element is carried out immediately - roofing material is laid in the hole. For stone, brick or rubble pillars it is arranged according to the finished product.
For the concrete option, a reinforcement frame is installed.
Install the formwork above ground level to the required height (minimum 40 cm).
Pour in the solution.

Tying a frame house on a strip foundation.
A grillage is arranged on the finished pillars. This is done according to the same principle as in a pile foundation. It may not be there, then a wooden beam is laid on the tops of the racks, which will serve as a support for the frame.

The final stage is the installation of a wall that fills the space between the pillars. A trench 20-30 cm deep is dug between them, the base is filled with concrete, and after it hardens, a wall is laid out. If this is not done, then the lower ceiling will require additional insulation so that the floor in the house is not cold.

It’s not at all difficult to make a columnar foundation for a frame house with your own hands. It is important to remember that building a basement with such a design is a very problematic task, so this idea should be abandoned. On the other hand, the foundation is built quickly and is much cheaper than a pile or strip foundation.

Dimensions and depth of the tape

Since frame houses are lightweight, the foundation for them does not need to be deepened. It is enough to maintain a size of 0.4–0.7 m.

When erecting a building in a northern climate, when the soil freezes heavily, a different approach is necessary.

The formula used is that the base of the foundation must be located below the seasonal freezing of the soil by a third of a meter.

Recessed foundations are also used when it is planned to build a basement under the building. In such a situation, the concrete strip becomes its walls.

It is not recommended to lay the foundation below 2.5 m from the soil level. If strong layers of earth are deeper, the strip foundation is replaced with another foundation option - columnar supports.

Frame buildings are secured on top of the strapping located on the tape. It is made from wooden beams or reinforced concrete beams. To increase the strength of the structure, the concrete structure itself is made wider. When the frame is planned to be faced with brick, the width of the tape is increased, making it up to half a meter.

The height of the foundation must be at least twice as wide as its width, so under normal construction conditions its dimensions are 0.6–1.2 m.

Wooden foundation.

A kind of hybrid of pile and column. A wooden foundation is suitable for building a small frame house, but due to its comparative fragility, it is rarely used for residential cottages. It is optimal for country houses: the impact of minimal loads on the base, low cost of installation and material, high speed of the device. In addition, the tree has natural elasticity, which allows it to regain its original shape after minor deformations from soil heaving.

The lightest designs have seasonal frame-panel houses. The foundation for them can be very simple. It is in such cases that wooden poles are used. Although in Venice, high-rise buildings stand on such foundations for hundreds of years, so one can argue about durability in this case.

Foundation pile for a frame house.

Certain types of wood are suitable for piles: beech, larch, oak, pine. Sections of wood with a diameter of at least 20 cm are suitable for blanks. The product can remain round or acquire a rectangular cross-section with a side of 20 cm. Piles are treated with special solutions that prolong the life of wood in unfavorable conditions. Before directly burying them, you should wrap the post with 1-2 layers of roofing material or other polymer material, then the soil will not stick to the product. This will allow the pile to slide relative to the base in a vertical direction when the soil is heaving, and will also preserve it for a longer period.

How to mount a wooden foundation for a frame house with your own hands:

Markings are made according to the already known scheme: corners - intersections - perimeter in increments of 1.5-2 meters.
Transfer the location of the pillars to the site.
Holes are dug in the ground with a diameter 1.5 times larger than the pile. The depth must exceed the soil freezing level and reach dense layers. If they are not available, the pole should be placed 0.5 m below the level.
Make a pillow of stones or a wooden cross.
Pour 15-20 cm of concrete mixture and immerse the pillars in it. When the solution sets, it will fix the pile.
The soil is backfilled and compacted.

Design selection and sizing

All types of strip foundations are built for lightweight frame buildings. The differences between them are in the installation method, materials and depth of installation.

The structure can be monolithic or prefabricated. In the latter case, concrete blocks are used, which are fastened together with cement mortar and reinforcement. The monolith is a continuous ribbon of rubble and crushed stone.

Foundations also differ in depth, which depends on the type of soil. Shallow ones are built on slightly heaving and dry soils. If the heaving is strong, buried ones are arranged. A minimum of equipment will allow you to make a strip foundation of any type. Each of them requires drainage work, insulation, waterproofing, and the installation of a sand cushion. These measures increase the service life of the foundation.

On slopes, the structure is subject to large shear forces, so installing belts there is not recommended. On fine sandy soils and embankments, the base is expanded with a concrete slab.

Tape depth

The depth of the strip foundation depends on the region where the structure is being built, as well as the total weight of the structure.

The weight of frame buildings is small, so the foundation for them is laid at a depth of 0.4 to 0.7 m. If construction is carried out in the northern region, where the soil freezes heavily, a different approach is required. The formula is used: the depth of the foundation base is 30 cm greater than the seasonal freezing of the soil.

Shallow foundations are built for lightweight structures. Recessed foundations are stronger and less susceptible to soil heaving. They are used mainly if they plan to build a basement under the house. Then the concrete base serves as its walls.

Laying a foundation deeper than 2.5 m is not recommended. If the bearing layers are lower, instead of building a strip foundation, another foundation option is used - installing supports from pillars.

Width, height of structure

Frame buildings are secured to strapping laid on top of the foundation. It is made of a reinforced concrete beam or wooden beam with a standard width of 15 cm. For the strength of the structure, the width of the concrete base itself should be 30-40 cm. If you plan to line the frame with brick, increase it to 50 cm.

The height of the tape should exceed the width by 2-4 times, which under standard conditions is 0.6-1.2 m.

Lightweight strip foundation.

Widely used among developers due to its low cost and high installation speed. A lightweight strip foundation for a frame house is used on solid foundations, where there is no need for large depths and massive support.

The main difference between this design and the usual one is the reduced depth of the sole and the dimensions of the tape itself. This is acceptable for lightweight structures, in particular for residential frame houses.

Dig a trench or pit (affects the presence of a basement). In any case, the width of the excavation should be 0.5 meters greater than the specified perimeter for ease of work. The depth depends on the groundwater level, on average - 0.8-1.5 meters (taking into account the design of the pillow).
Mark the perimeter of the foundation wall. It is important to correctly measure all angles and check the parallelism of the sides.
Install the formwork. Its height is determined by the presence and size of the base, but not lower than 40 cm above ground level. The width of the future tape is calculated as the wall thickness + 100 mm. For a light frame house, you can make 200-300 mm.
Fill with a pillow made of ASG (10-20 cm).
Install the frame.
Concrete solution M300-M400 is poured.

Do-it-yourself strip foundation for a frame house.
A lightweight foundation for a frame house is convenient because it does not require special preparation and installation of additional structures for the construction of walls.

Soils are not always conducive to standard construction solutions. There are many areas in Russia with clayey and highly heaving soils. But this is not a reason for them to be empty. Even for such cases, there are solutions.

If you happen to purchase a plot of land with floating soil, it is advisable for construction to arrange a slab monolithic foundation for a frame house. It is quite possible to do this with your own hands. The technology is similar to creating a lightweight tape:

A excavation is made in the soil to the depth of the fertile soil layer and the upper exposed layer is compacted.
Next, arrange a gravel-sand cushion about 20 cm thick.
Roll out 2-3 layers of polymer waterproofing.
Pour a preparatory layer of concrete up to 5 cm.
Mount the frame. It must be solid, since the slab takes significant loads from the ground. For meshes, take thick reinforcement with a diameter of 12-16 mm, lay it in increments of no more than 40 cm in both directions. The rods are tied with wire. Make 2 planes and connect them to each other at a distance equal to the height of the slab (10-15 cm), minus the protective layer of concrete (up to 5 cm).
Pour in the solution. You will need a lot of it; you should not choose low-quality concrete in order to save money. The optimal brand is M300-M400.

Foundation slab for a frame house.
The monolithic slab is located at ground level, and involves the construction of a basement and a basement (it serves as the floor). A more massive and recessed one is not needed for a small house; this type is used for large buildings.

Strip foundation calculations

Before making a foundation for a frame house, you need to make the necessary calculations. Foundation calculations depend on:

types of soil at a construction site;
presence of a basement in the house;
determining the size of the house and the materials used, and ultimately all the loads on the house;
availability of groundwater and depth of soil freezing.

Calculations of a strip foundation for a frame house

Soil characteristics are carried out in special laboratories. You can take soil samples from the construction site yourself and take them to the laboratory, or you can call geological engineers. It depends on your financial security. If you decide to conduct the research on your own, then you first need to dig a 1.5 m trench and examine the soil from it. You may have the following soil types:

rocky;
sandy;
clayey
rocky;
gravel.

Gravel soil is best suited for foundations. It does not swell and does not retain moisture. And fine sandy soil is practically unsuitable for construction. Clay soil causes displacement.

When calculating the total load on a house, you can use this method: 1 linear meter of a house with a wall height of approximately 3 m weighs 1.7 tons. If the house has one floor, then multiply the perimeter by 1.7. And if the house has two or more floors, then the perimeter of the house is multiplied by the number of floors and by 1.7. It must be remembered that the fate of the entire house depends on the durability of the foundation.

Construction of the foundation

Insulation and waterproofing.

The foundations of a wooden frame house require special finishing. Waterproofing is desirable for all structures below grade for any material. This way the elements are better preserved. This is especially true when the groundwater level is high.

Thermal insulation of the foundation and basement walls will ensure minimal costs for insulating the floor of the first floor. In those houses where there is no basement, the space between the ceiling and the ground can be filled with expanded clay and sand. These materials prevent heat from being drawn out from the lower room. To prevent them from getting wet, you can line them with a roofing felt sheet on both sides.

The walls of the strip foundation and grillage are laid on the outside with polystyrene slabs.

Recommendation: A good review article that introduces you to strip foundations for a frame house. Please study this article well. You'll figure it out. What is a strip foundation and what is it used with? But before you start building the foundation, study the topic of a frame house in more depth.

Shallow strip foundation on piles

It is recommended to build MZLF on piles in cases where there is no confidence in the homogeneity and strength of the load-bearing soil. This design does not have the disadvantages of a shallow strip foundation.

The main part of the load from the building - 85% - is carried by reinforced concrete bored or metal screw piles, resting on the ground below the freezing level by 20-30 cm. The grillage is made in the form of an MZLF, connecting the supports to each other. It transmits forces evenly to the underground anchors and the ground surface through the sole.

This option is more stable, has high rigidity, and is reliable in loose underlying soils.