Foundation for a frame-panel house. Construction tips from Semenych

How to make a columnar foundation from concrete blocks?

For a frame or wooden structure, the most rational foundation is considered to be a columnar one.
The main advantage of arranging supports for a structure in the form of pillars is the simplicity of the technology and a minimum of preparatory excavation work. The most common and fairly reliable materials for constructing foundation pillars are small-piece solid concrete blocks. You can quickly build a columnar foundation from 20x20x40 cm blocks with your own hands; the technology is available for non-professional execution. An important factor in favor of using foundation blocks can be considered cost: the price of one high-quality product does not exceed 50 rubles.

Types of columnar foundation

There are various classifications of foundation types made from columnar supports. Foundations are distinguished by the shape of the pillars: round columnar, a base with square supports, and pillars with a rectangular cross-section. According to the method of constructing the foundation, monolithic pillars are distinguished - with digging a trench, installing reliable formwork, pouring a concrete mixture, and a foundation using prefabricated technology made of bricks or blocks.

Let's learn more about the nuances of how to install a columnar foundation with your own hands; a video fragment is presented below.

Columnar foundations are classified by the depth of the pillars underground. The deeply buried type is installed on clayey or heaving soil areas, with the column located below the level at which the soil freezes in winter, about 1.5 meters.

Installation of a columnar foundation for a frame house with a slight depth is advisable at a depth of no more than 0.5 meters - it is installed on a sand bed. It can also be mounted on a gravel bed when there are sandy and heaving soils. Another type of columnar foundation, when the supports are not buried. This foundation is ideal for light-weight country houses, and is most often used on sandy soils.

Blocks for foundation pillars: basic requirements

The main criteria for self-construction of a house or other structure are considered to be the availability of understanding of construction processes, as well as the possibility of using simple, lightweight and small-sized materials. Wall blocks made of monolithic concrete are the most appropriate material for building foundations, subject to the following conditions:

optimal dimensions: 400 mm length, 200 mm width and height;
geometric shape - a regular parallelepiped with precise angles and dimensions;
a monolithic concrete block should weigh within 35 kg;
the structure of concrete can be rough, but smooth, without chips, growths, cracks and potholes;
voids in foundation blocks are unacceptable;
concrete must gain strength of at least 70% of the design value, that is, lie from production to use for at least 28 days to gain natural strength;
a simple check of quality and strength: when a block is lightly hit with a hammer, it bounces off, and when dropped from a height of 1 m to the ground, the block does not receive damage.

Plan and layout of the building on the site

According to the rules, the breakdown of a building on the ground for the construction of foundations should be carried out along the axes of the building. But in practice, it is easier to arrange the dimensions of the building along the outer perimeter. You should not plan “by eye” or by drawing the outline of the building on the ground using the Pythagorean theorem for angles.

Hiring a specialist or renting geodetic instruments, theodolite, level, range finder and the like will be inexpensive, but will save you from troubles and additional costs during construction.

Foundation marking

It is recommended to mark the locations of foundation pillars according to generally accepted average norms and rules:

foundations - pillars at the corners of the building are required;
additional pillars are installed at the junctions of walls and partitions;
the optimal distance between pillars is 2 - 2.5 m, maximum - 3 m, minimum - 1.5 m.

Do-it-yourself columnar foundation for a frame house

Initially, strictly vertical holes with a depth of 1.5 m or more are drilled to lay the foundation pillars. In the case of clay soils, such work cannot be carried out during the rainy season.

At the next stage, you can simultaneously pour both the pillars and the grillage, or alternately, but the concreting process as a whole should take no more than 24 hours for good adhesion of the individual layers.

This process is carried out in parallel with the connection of the reinforcement frame for the pillars, having decided on the reinforcement scheme.

The height of the reinforcement bars must necessarily reach the bottom of the pit, but free ends 50 cm long must remain. After installing this frame in the hole (it is desirable that the rods rest against the concrete solution to prevent the corrosion process), the pouring is carried out directly.

In this case, the ends of the reinforcement are bent at an angle of 90 degrees and are used to stitch the grillage.

Having installed the grillage formwork, you should tie up the reinforced frame of it, and insert it into the formwork, and then tie it to the rods of the pillars. This method of fastening is more reliable and rigid than using welding. Before pouring the grillage itself, install studs to secure the strapping beam.

If the grillage is low, you can strengthen it by backfilling; if it is high, you can immediately install the formwork.

The organization of embedded holes for the so-called vents is carried out using a regular 100 mm pipe.

Concrete should be poured in layers of 15 cm with each layer completely compacted. This is very important to prevent the formation of voids that are destructive to the foundation. The consistency of the concrete should also be uniform.

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Construction of columnar foundations

Approximate step-by-step instructions for foundation work:

When laying out a building on the ground along the external projection, marking cords are pulled.
Along the entire perimeter of the structure, a layer of plant soil 15-20 cm thick and 50-60 cm wide should be removed, offset to the outside of the building. This is necessary for the subsequent device for collecting the base.
The locations of the foundation pillars are marked with pegs in the center according to a pre-compiled sketch plan for the layout.
The excavation depth for constructing shallow foundations is usually no more than 40 cm.
With deep foundations (for example: below the freezing depth), the use of blocks is irrational due to the difficulties encountered in laying the blocks and the increasing volume of excavation work to facilitate high-quality installation.
The soil, if possible, is removed in an area minimally larger than the cross-sectional dimensions of the pillar. Typically, a columnar foundation is arranged square with each side measuring 40 cm.
The bottom mark of each hole must be the same for all pillars; the mark is checked using a level or other methods.
The preparation or cushion for the blocks is usually made of a sand and gravel mixture. Only sand bedding can be used.
Compaction of the underlying layer is carried out using a manual tamper made of logs. The sand layer can be compacted well by simply pouring excess water.
The first (bottom) row of two blocks is laid directly on a sand-gravel bed or on a leveling layer of cement-sand masonry mortar.
The gap between the blocks is filled with a solution about 1 cm thick.
The laid row of blocks is covered with mortar and the next row overlapping perpendicularly is laid on it.
Similarly, with overlapping, all rows are laid to the desired level.
Cement-sand mortar is prepared at the rate of 1 part of M400-500 cement and three parts of sifted sand. Water is added in the amount necessary to create a plastic thick consistency of the solution.
The top mark of the pillars is checked. It must be the same for the entire system. If necessary, it is possible to add leveling layers of mortar; in some cases, the top row can be laid out of red solid brick.
An anchor bolt is sometimes inserted into the seam of the top row for subsequent fastening of the wooden frame
The last stage is the installation of roofing felt waterproofing on bitumen mastic covering the top row.

Video: DIY frame house on blocks

How to do

So, all calculations have been completed, materials have been prepared. Now you can proceed to the actual construction of the columnar structure. This is not difficult to do and does not take long. In addition, this option is perfect for those people who do not have much experience in the construction industry.

Site preparation

Before building the foundation, it is necessary to carefully prepare the site itself. To do this you will have to use the following plan:

Remove all debris and top layer of soil from the site . When performing the second point, it is necessary to remove a layer of soil to a depth of 18-20 cm.
Level the surface.
Mark the site according to the plan . For these purposes, prepare wooden pegs and drive them into the soil at the corners of the future house. Pull the cord through them and measure the accuracy of the markings according to the project.
Mark the places where you will need to dig holes for tables . Recesses should be located at every corner of the future structure, as well as in those places where partitions and walls intersect. There should be a distance of no more than 1.8 m between each pillar.
Using a special drill, dig holes.

The video shows how to make a columnar foundation for a frame house:

Foundation sole

If the construction of the foundation will take place on sandy and gravel soil, then level the bottom under each foundation and fill it with a cushion of small crushed stone. Next, compact it tightly. Fill everything with liquid cement. The thickness of the finished concrete base will be 20 cm. These measures are sufficient for the construction of a frame house. The formwork is installed even before the concrete base is completely dry. It is extremely important not to miss this moment.

On clay soils, it is necessary to prepare a bed of gravel or sand. In this case, it should be 40 cm wider than the body of the base. After laying out the material, it is watered with water and compacted. The thickness of the pillow will be 25 cm. The blocks are installed directly on the pillow. For a frame house there is no need to reinforce the base. But this article will help you understand what a pile screw foundation looks like, and how you can make it yourself.

The video shows the base of a columnar foundation:

Formwork

To reduce costs and speed up work, it is necessary to use inventory, ready-made panel formwork. Thanks to its prefabricated panels, it is possible to change the dimensions of structures and the degree of angles. In addition to boards, moisture-resistant plywood, iron and plastic can act as formwork. The boards should be narrow so that they do not crack and become damp. So before installing, moisten them with water.

Columnar foundation formwork

If the soil is dense and dry, and the walls of the recess are not crumbling, then you can forget about the formwork. Roofing material is laid along the perimeter of the recess so that water from the solution does not seep into the ground. There is no need to remove the roofing felt further, as it will act as waterproofing for the supports. Asbestos pipes installed instead of formwork should also be left in the ground. But what is the required consumption of bitumen mastic for waterproofing the foundation, and how it should be used, this article will help you understand.

There is also a simpler and more cost-effective option for constructing formwork. Using roofing material, form it into a pipe of a size that is equal to the size of the pillars indicated in the project. To prevent the roofing material from unfolding, it is necessary to wrap it with tape around the circumference from the outside.

Installation of the roofing felt slab is carried out vertically on the pillow. To prevent it from moving, it should be fixed with knocked down wooden planks.

Reinforcement and pouring of concrete

Reinforcement of the poured base is carried out by a frame. It is made from 4 steel stubbles, the size of which is 10-12 mm. Intercept them every 25 cm with wire clamps. This will prevent the reinforcement from diverging on the sides. You can replace the reinforcement bars with a pipe that is installed in the center.

Reinforcement and pouring of concrete

Fill the bottom of the formwork with mortar. Its thickness is 14-20 cm. While the solution has not yet dried, install a pipe core in the center. The frame is installed so that a distance of 2 cm from the walls is maintained between the reinforcement bars.

For filling, use M200 mixture. It includes sand, gravel of 3 different fractions and water. The mixture is laid in 30 cm layers and then compacted. When the pouring has been completed, you need to check the installation horizon. If the top edges of the pillars are not the same height, then you will have to balance the height using a grillage. To do this, use 1 part cement and 2 parts sand. The formwork remains intact for 7 days. It will also be interesting to learn how the framing of a frame house on a strip foundation occurs.

Waterproofing and grillage

After removing the formwork, it is fashionable to move on to insulating the pillars from moisture. For these purposes, coating or roll materials are used. The most commonly used materials are roofing felt, fiberglass, liquid glass and resin. To fill the spaces around the structure, it is necessary to use clay. It will be laid in a layer of 30 cm, and the loan will be compacted.

Waterproofing and grillage

A grillage is a lintel or belt that serves as a connection for the upper parts of the pillars. It is performed to give the pillars stability and protect individual bases from shifting. You may also be interested in learning about how to strengthen the foundation of a wooden house.

Pickup

This is a type of plinth that serves to eliminate the distance between the supports from the frame to the ground. Thanks to the fence, it is possible to protect the structure from the penetration of animals, precipitation, and is also an opportunity to maintain a stable seasonal temperature.

Picking up a columnar foundation

When building a frame house, a columnar foundation is often used. This is one of the simplest and cheapest ways to obtain a strong and reliable foundation. And although its construction is not that complicated, it is better to entrust this matter to specialists if a person has no idea how to make calculations, what materials to choose and how to directly carry out construction work. Read a separate article about a pile foundation with a grillage.

Columnar foundation made of blocks - where to use them

Of all the known construction options, the most inexpensive and reliable is the construction of a wooden house, bathhouse or utility structure, the basis of which will be a wooden frame erected on a columnar foundation made of blocks. It should be noted that this type of foundation does not imply the use of blocks or other reinforced concrete analogues that differ in significant mass. Let's talk about how to make your own block foundation from elements whose mass does not exceed thirty kilograms.

Advantages and possible disadvantages of a columnar foundation

A columnar foundation is a simplified version of a pile foundation. The structure is a network of supports installed around the perimeter of the walls and in places of greatest load. The maximum step between supports is 2.5 m. All pillars are connected to each other by a grillage (horizontal strapping). Columnar foundations for frame buildings are used in 2 types: monolithic concrete (made by pouring into supports) and prefabricated (constructed from ready-made blocks or stones). Despite the fact that the structure is constructed without completely pouring concrete over the entire perimeter, such foundations have a number of advantages that make the structure reliable and durable.

Columnar foundation for a frame house

Advantages of a columnar foundation:

Costs less than tape analogues;
Can be made by yourself;
Quickly erected;
Its construction does not require heavy equipment;
Easy to repair;
The poles can be installed at any time of the year, including winter.

The disadvantages of the design include a large amount of manual work (if there is no drilling equipment) and the need for additional insulation of the floors, since the frame structure practically hangs in the air.

Blocks for columnar foundation

For this purpose, block material is used in the form of monolithic elements cast on a vibrating machine or press from a concrete mass of m100 - 150.

You should not try to make blocks yourself - purchasing them is much easier and cheaper. Moreover, you will need no more than five dozen pieces for the foundation.

To construct a columnar foundation made of blocks, elements with dimensions of 20 x 20 x 40 cm are used. And there are reasons for this:

the parameters of the block indicate a small mass of material. Taking into account the filling component used in the manufacture, the weight of one stone can be 30 – 32 kg. This makes it possible to carry out installation work without the use of special equipment;
A brick press and standard molds are used to make blocks. The result is a cast block, which is significantly stronger in strength than analogues produced by handicraft methods;
the successful dimensions of the material create the opportunity for simple laying out of foundation columns and leveling the plane without trimming the supporting tops.
Roughness is allowed on the block surface, but it must remain smooth and not have chipped areas, cracks, growths and potholes;
void spaces in the block are not allowed;
After manufacturing, the block must gain its design strength within four weeks.

Stage-by-stage execution of work

Step-by-step instructions for constructing a columnar foundation made of blocks are as follows:

Preparation

A plan for the future facility is being prepared, on which the locations for the pillars are marked. As a rule, they are located under each corner section and under the intersection points of the walls. In a straight line, the distance between two posts should not be more than two meters when the design solution includes a grillage made of metal or wood. For a reinforced concrete grillage, a distance between supporting elements of up to three meters is allowed. If this condition is not met, then manifestations of a deformation nature will occur.

According to the drawn up plan, the need for building materials is clarified using mathematical calculations.

Let's move on to marking work. To begin with, we outline the two most distant marks, which will serve as guidelines for the dimensions of the structure.

The diagonals are measured, the supports for the main and auxiliary purposes, and the columns for the partitions are marked. The markings are carried out along the axes of the future walls: the pegs are placed outside the building area.

Excavation

We continue to build a columnar foundation from blocks with our own hands. We begin to dig holes measuring 1.2 x 1.2 m and a depth of 1.5 to 2 m under each pillar. To speed up the process, you can rent a motor drill. The pits are prepared in such a way that after laying the blocks their upper levels coincide.

At this stage of work, it is recommended to install communications and dig trenches around the perimeter intended for arranging drainage and insulating the basement.

A pillow arrangement is provided. It doesn’t have to be done on sandy soil, but in other areas it won’t be superfluous to install a cushion. A twenty-centimeter layer of sand is poured onto the geotextile material, wetted and compacted. After this, a crushed stone layer of the same height is arranged. Having compacted the pillow, it is necessary to arrange a footing. If the groundwater is close, you should fill the crushed stone with a layer of forty centimeters, which will help maintain the geometry even with excessive moisture.

If a non-residential structure is being built, then the load-bearing platforms can be abandoned and the blocks can be laid on sand. But it should be remembered that the base of a columnar foundation made of concrete blocks must be at least 40 x 40 cm.

Sole device

To expand the base, the foundation is mounted on reinforced concrete slabs cast into formwork structures. At this stage there are certain nuances:

the parameters of the slab must be twice the cross-section of the column in order to compensate for lateral impacts from heaving soil;
the waterproofing layer of the sole will significantly extend the service life of reinforced concrete;
It is better not to use crushed stone, as its sharp edges will break through the waterproofing material.

For this reason, many people prefer to build concrete bases from thin concrete mixtures.

To protect against groundwater, a drainage system of smooth perforated pipes is installed. They are placed in ditches, wrapped in geotextiles and sprinkled with crushed stone, then covered with soil.

Block laying, concrete pouring, waterproofing

When constructing a columnar foundation made of concrete blocks, a sand-cement mortar mixture is used. The posts are connected to the sole with a reinforcing rod running through the center.

Masonry work is carried out as standard. Dressing is necessary for each row. To do this, take several reinforcing rods, connect them with knitting wire, and place them in a hole. Concrete is poured in layers of thirty centimeters and compacted. A half-meter pin is installed at the top of each column.

When carrying out masonry work, it is necessary to control angles and horizontal lines.

If the design specifications provide for a grillage, then in the last row a reinforcement fill is installed, which is necessary for connection with horizontal beams.

If a non-residential building is being built, then the blocks can be laid without connecting them with mortar. In accordance with the technology, the pillars are laid out to a height of 0.5 - 0.8 m. For this purpose, formwork is arranged, into which concrete is then poured.

The blocks do not require time to settle; their edges can be waterproofed immediately. The surface of the stones is treated with bitumen or epoxy compounds. A carpet made of roofing felt or polyethylene materials is laid around the entire perimeter of the sole. The edges should be clamped so that when pouring the mortar mixture, the insulating layer does not move under its weight.

Grillage installation

This type of foundation is used on non-heaving soils, is buried less than a pile foundation, and is significantly subject to lateral movements. When building a light structure, the tops of the columns are not fastened together, but when arranging a residential building, you will need a grillage.

Its reliability improves the stability indicator by distributing the load effects between the support pillars.

If you need to create a practical monolithic grillage made of reinforced concrete, you will have to install a formwork structure and create a reinforcing frame. The concrete solution is poured at a time, and at the same time it is compacted with vibrators.

After stripping, the edges of the grillage are protected with a waterproofing layer.

Several types of grillage are known:

slabs connecting pile heads;
tapes holding the tops of the posts together.

Ground and buried grillages are easier to install, because the soil plays the role of the lower shield in the formwork.

Pickup

This is the final touch in arranging the foundation. The fence is a wall that hides the distance from the ground to the grillage. Concrete solution is poured into a ditch thirty centimeters deep and 10-20 cm wide. Subsequent construction work is carried out after the concrete has hardened.

At the end of the work, a layer of waterproofing material is laid. The roofing felt material used to cover the pillars is excellent for this.

Foundation for a frame-panel house

Question:

Hello! One company ordered a two-story frame-and-panel house measuring 6*4. In the basic configuration they have such a foundation. Reinforced tiles 40*40*5 and blocks 200*200*400 and they simply install the whole thing on the ground. As far as I understand, it’s better not to put it on bare ground, at least make a sand cushion. There are 12 points under this house, that is, 12 slabs and 12 blocks. Or make a pile-screw foundation? Or leave it as is and just add a sand bed? Please tell me what to do. The dacha is located in the Smolensk region, near the city of Gagarin. But I don’t really want to spend money on an expensive foundation. Thank you!

Maxim, Moscow.

Answer:

Hello, Maxim from Moscow!

It is difficult to unequivocally answer your question about the foundation for a two-story frame-and-panel house measuring 6/4 meters.

Everything ultimately depends on the place where the house is built and the characteristics of the soil underneath it.

The Smolensk province is large, the places in it are different, and I’m not talking about the soil at all, even on 8 acres it can differ significantly at a distance of 6 meters.

It is clear that everything comes down to the despicable metal. The cost of a point foundation made of tiles and concrete blocks is tens of times cheaper than a pile-screw foundation.

Let's talk about this topic together. First of all, about the input data. You write about 12 support points at home. Accordingly, 12 tiles and 12 blocks of the sizes you specified. Given the size of your home, this is clearly not enough. For a very light one-story frame-panel utility block, this quantity could be enough. For a two-story house - under no circumstances.

According to all building regulations, supports should be located at a distance of about one and a half meters from each other. Sometimes they are placed every 2 meters, but such gaps between them can no longer guarantee one hundred percent reliability of the stability of the structure. In your case, this is possible with a certain arrangement of the blocks, when along the 4-meter side of the house the blocks are laid longitudinally and not across.

That is, take a sheet of paper and draw a sketch of the foundation. With three support points along the 4-meter width of the house, it is necessary to have 5 support points along its 6-meter length. Consequently, there are 12 reference points along the perimeter of the walls. But don’t forget about the supports for the floor joists, and there will be at least 3 more of them. Otherwise, 4-meter-long joists will only rest on blocks under the walls and sag at such a length, not to mention 6-meter long joists.

In addition, when constructing your house, the corner support points and the intermediate 6-meter-long ones in the middle are usually made not in one block, but in two. And considering that the block has a height of 0.2 meters, this is completely insufficient for a home. The base of the foundation (that is, the part of it that rises above the ground) is never made as such. In a snowy winter, it will be covered with snow; the height of the snowdrifts near Gzhatsk, that is, Gagarin, can be up to half a meter. Your frame beam at home will get wet with all the ensuing consequences.

Yes, and support subsidence is very likely. More than once I had to observe this in houses that had stood for ten years, when they, having sunk the supports, simply lay on the ground with their foundation.

Therefore, at a minimum, the blocks must lie on top of each other to achieve at least 0.4 meters in height.

Let's skip all these calculations and just say that you need to have 15 tiles and 46 blocks. And not 12 and 12 at all.

And taking into account the blocks and tiles under the porch and the fact that some of them will fall apart during transportation, you will have to bring about 20 tiles and more than fifty blocks to the site. If something happens, there will always be somewhere to put the extra ones.

Next, we’ll talk about the construction site and the characteristics of the soil under the house.

To do this, you need to have the best possible understanding of these very important and significant things. Ideal soils are sandy and evenly distributed over the entire construction area, which has no slopes and is located at some elevation in relation to the surrounding land.

In such areas, the foundation is placed, which we discussed above. And it is placed as follows - they dig holes approximately to the depth of a spade bayonet in order to remove the top fertile layer of soil. The said sand is poured in a layer of at least 10 centimeters or a little more. It is spilled with water, compacted, leveled. The tiles are laid in such a way that their surface protrudes above the surface of the ground by 3 - 5 centimeters, that is, by the thickness of the tile.

Then, either one block is installed on the tile on top of another (more often using mortar than without it), or the first row of two blocks folded together, then the second row, with an overlap (the joint is perpendicular to the bottom one), in the corners and in the middle of a 6-meter wall. Waterproofing is laid on the upper surface of the support.

Sometimes it is possible to install a similar foundation on other soils. But without examining your site, I cannot speak about such an assumption. For more qualified advice and consultations, you need to invite a specialist builder. You can, of course, wander around the area yourself and see if there are similar foundations in buildings of the same type as your house. And how they behave for several years after construction.

As for the pile-screw type of foundation, today it is “all-weather” and is installed practically without any in-depth study of the soil characteristics. Especially on slopes. Of course, it must also be installed in compliance with the recommended technologies. That is, strictly according to the level, appropriate depth, priming of surfaces, pipes of a certain diameter, metal wall thickness, filling the cavity with concrete, installing upper brackets, etc.

If the contractor company (the one that is going to build your house) can guarantee you that for three to five years they undertake to accept claims from you in case of deformations of the foundation and the house, then agree to its cheap version of point supports made of slabs and blocks. Only they do not give such guarantees, and if they do, they are reluctant to comply with lawsuits, if by that time they do not cease to exist at all.

Many clients, of course, choose cheaper foundation options for “average lousy soils,” although after a few years they sometimes have to deal with some problems (but not always!). Correcting the distortions then most often falls on their shoulders.

So it’s up to you to decide on the type of foundation. If you still choose block construction, then in your contract with the company, include clauses on adding a compensation layer of sand under the tiles and increasing the number of supports and blocks. According to the above calculations. But this is in my opinion, and then you know.

Good luck!