Building a columnar foundation with your own hands is not difficult. The main thing is the difference between a regular tape and a supporting structure based on pillars. In the first case, a strip foundation is erected directly on the ground, and in the second, pillars are mounted and a grillage is installed on top.
Types of columnar foundation
The type of columnar foundation is selected depending on the type of soil.
They are divided into two types:
Prefabricated columnar foundations are erected in areas where there is groundwater or the soil is very frozen. This type can be made faster than a monolithic one. But if you compare it in terms of strength, the latter is undoubtedly better.
A columnar foundation is also good for areas with large surface slopes
Depending on the degree of penetration into the ground, they can be:
- recessed; shallowly recessed; not recessed.
Their construction differs somewhat in technology. In this article we will talk about how to make a non-buried tape columnar foundation with your own hands.
Calculation and marking of column-strip foundation
One of the main points that you should pay attention to when erecting wooden buildings is preparing the area and correct marking. After all, the future strength of the entire structure depends on this.
The calculation and marking of the column-tape base can be done independently, with a minimum of tools.
Before carrying out any work, the site for construction should be carefully prepared. Best option in this case, when the soil is dry and homogeneous. Experts recommend additionally finding out how much the soil in this area can freeze to prevent the walls from collapsing.
The foundation is usually laid 20 cm below the freezing depth. A slight slope is acceptable construction site in any direction except north. This is provided for the drainage of rain and melt water.
Required materials and tools
To mark a columnar foundation with a grillage, you cannot do without the following set of tools and materials:
- construction tape; linen cord; construction level; wooden pegs, the length of which is 50 cm; right triangles.
Scheme for calculating a column-strip foundation
Marking begins from the inside; this is where the first corner of the future structure is set and the peg is driven in. Next, use a triangle to measure the dimensions of the outer part of the foundation.
It is necessary to mark the area with an accuracy of several centimeters in the difference in diagonals
On one side, the length will be equal to the size of the longitudinal side of the wall, and on the other, the transverse side. Two more wooden pegs are driven in at the intersection of the axes. The remaining corners of the future structure are measured in the same way.
The next stage is performing cast-offs.
It is as follows:
- secure the boards to special poles installed next to the driven pegs. They are fixed at the height of the future floor of the building, no higher than 1.5 cm from the soil itself; check that the marks are set correctly; when building a columnar type with your own hands, it is important to pay attention to the axial dimensions. They are applied along the top of the cast-offs, and then nails are driven in and a clothesline or cord is pulled on all sides.
Calculation of a columnar foundation with a grillage
If you need to build a columnar foundation with a grillage with your own hands, first of all you should calculate how many supports you will need to make in order for it to be used for a long time.
As in the previous case, work begins with geological surveys in order to determine the bearing capacity of the soil. This indicator can help calculate the area of support, information about which can be easily found on the Internet or specialized literature.
The resulting number must be divided by the weight that 1 cm2 of soil can support. This will be an indicator of the area of the foundation. For the final result, it is necessary to add 30% to the resulting figure as a safety margin.
In order to make the calculation required quantity pillars for columnar base with a grillage, the supporting area is divided by the area of the base of the support.
This type of foundation is extremely popular precisely because of its simplicity, strength and the ability to do all the work with your own hands in the shortest possible time, even without much effort. construction experience. And by comparing the prices of the material, you can calculate that it will cost 1.5-2 times cheaper than any other type.
But it also has a drawback that must be taken into account at the design stage. It is highly not recommended to build it on moving soil, as well as in areas where groundwater flows or large differences in height are observed.
How to make a columnar foundation with your own hands
At its core, a foundation is a system of supports located:
- at the corners of the building; at the intersection point of the walls; under supporting structures.
If a stone oven is planned on the ground floor, then it is also better to lay support piles under it
Before performing any work, be sure to draw up a detailed future design and then try to strictly adhere to it, taking into account all the documentation for the project. Then the building is guaranteed to be able to stand for a long time.
The possible load on the foundation is also of great importance when choosing a support.
So, you need to take into account the following parameters:
- approximate weight of the future building, furniture; number of residents; weight of the base and the entire building; snow load.
This determines which material is best to choose and how much of it is required.
It must be filled in time before winter arrives, because if left for this period, it will become deformed and you will have to start all over again.
To build a columnar foundation with your own hands, you need to stock up on the following tools and materials:
- reinforced concrete, concrete or brick supports; reinforcement; boards for formwork; sand; crushed stone; cement.
For formwork, it is better to take a board whose thickness is 20 mm.
You can, of course, purchase special metal plates or particle boards for these purposes, but the cost of wood is much lower. Next, the following work is performed: assemble boards from the boards, and boxes from them; insert them into a pre-prepared depression in the soil on site where the supports are located; completely moisten the inside of the surface of the box with water. This will prevent water from being absorbed from the concrete and will make it easier to dismantle the box after the concrete mixture has dried. Then it is necessary to reinforce the foundation using reinforcement with a diameter of 12-16 mm. It is better to place it inside the box so that the edge of the reinforcement does not reach the walls of the box 5 mm . For a longitudinal arrangement, rods with a diameter of 6 mm are used, welded after 30-40 cm.
After the grillage frame is completed, the excess rods are simply removed. Lastly, the columnar foundation is insulated and waterproofed. This work increases the service life of the foundation. But this is not typical for all types of foundations. For example, a screw foundation does not require waterproofing and insulation work. Experts recommend that it is better not to weld the reinforcement, but to tie it with wire
Cost of erecting a columnar foundation
The cost of the finished product depends on many indicators:
- the area where the future building will be located; on the type of soil; on the width of the base and its depth; on the materials used for the construction of the columnar foundation (their quality, size, manufacturer and type).
When hiring specialists, in addition to these parameters, the volume of work and the number of workdays are taken into account. It should be noted that the price for building a monolithic strip foundation is slightly higher compared to other options.
Prices for the construction of a columnar foundation for 1 linear meter, considering different types concrete are given in the table:
Foundation size Brand of concrete, (diameter of reinforcement, mm) Price per 1 linear meter (RUB) 300 x 500M-200, (B-7.5) 4200 300 x 500M-300, (B-22.5) 4100 300 x 800M-200, (B-7.5 )6750300 x 800M-300, (V-22.5)6850300 x 1000M-200, (V-7.5)8400300 x 1000M-300, (V-22.5)8500300 x 1200M-200, (V-7.5)10100300 x 1 200M-300 , (V-22.5)10200
The cost of the foundation itself is relatively insignificant, which will reduce the overall construction costs wooden house or a bathhouse in a summer cottage.
More information about the stages of constructing a columnar strip foundation with your own hands can be seen in the video:
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A special method called columnar strip foundation houses are increasingly being used to build their own homes.
Previously, it was used mainly in areas with permafrost, where the production of the usually used base in the form of a concrete strip was impossible due to thawing of the soil, loss of its strength and entailing significant deformations of the building. Such methods were also very common in areas with seasonal flooding by river flood waters. Water easily passes under the ceiling without causing any damage to the walls of the building.
However, the manufacturing technology of a strip-column foundation is not complicated and has the main advantage for ordinary low-rise brick and wooden buildings.
There is no need to dig deep trenches under the concrete strip, because it can either be raised above the ground to a height of up to one meter, or its load-bearing elements in the form of horizontal beams under the walls can be buried into the ground to a small depth, since there will be practically no influence forces arising due to seasonal or simply temperature changes in soil characteristics. A combined strip-column and regular foundation can also be installed, which is used in the construction of houses on plots with a large slope. One part of your house can be cut into the mountain, and the other can rest on pillars with a beam system.
The support system under consideration consists of pillars that must withstand the load from structures such as floors and walls - often this is a massive frame cage of beams - a grillage, which absorbs the loads from the building wall and redistributes them to the foundation supports buried in the ground.
The pillars can be made from ordinary clay bricks, rubble stone, concrete, and also be installed in the form of bored concrete piles.
The beam grid (tape), also called a “grillage,” is often made of concrete with reinforcement from rolled structures - channels, I-beams used as reinforcement, as well as periodic profile rods.
Excavations in the ground for making pillars for grillage beams can be made in two ways:
- digging holes under posts in the ground; using manual and mechanical drills.
Horizontal beam structures are usually 0.45...0.6 m high, but the safest thing to do is not to engage in design, but to entrust the calculation of beams to an experienced design engineer. Otherwise, the construction of a strip-column foundation can be done with your own hands.
Columnar strip foundation. Step-by-step instructions or guide to action
Layout and marking of the construction site along the axes of the house. After planning, use a cord to break the axes for the construction of walls. Determining the places on the ground where holes for posts will be located or holes for vertical supports will be drilled. The distance between them should be from 150 to 200 cm .Important! the pillars must certainly be located in the corners of the building, as well as at the junctions of the internal and external walls, regardless of the chosen step of their location. Excavation work to construct pits for posts or wells. For brick, rubble and monolithic pillars, pits are torn off.
When a strip-column foundation is used, the laying depth should be 20...25 cm greater than the depth of soil freezing at the construction site. Production of formwork. It is allowed to use plastic or metal panels. You can make it yourself. For this, it is necessary to use boards 25...30 mm thick, from which boards of the required size are made.
A description of making boards with your own hands is very easy to find in any construction reference book. Knitting of reinforcement. If used monolithic concrete, it is subject to reinforcement. For the posts, a frame is connected from 4 reinforcement rods with a diameter = 16...18 mm, tied in height with closed loops made of wire with a diameter = 6...8 mm and installed in increments of 0.4 m.
All rods and clamps are connected to each other with tying wire. The height of the frame must be 250 mm higher than the height of the column in order to be able to tie together the support reinforcement with the horizontal beam structure. Reinforcement must be used at least class A-3. Brick, masonry, concreting pillars or bored piles.
If brick is used, it must be reinforced with a 100 x 100 mm wire mesh every five rows. Rubble stone masonry does not need to be reinforced. Concreting of monolithic columns is carried out with concrete of class B-25 (M350).
Concrete can be used either imported or made with your own hands. During work, mandatory vibration compaction is required. Columns can have a section of 0.6 x 0.6 m for outer wall(with a thickness of 0.6 m) and 0.4 x 0.6 m for the internal one (with a thickness of 0.4 m). Preparation for concreting horizontal beams.
If the bottom of a horizontal beam structure must be below ground level (usually 25...30 cm), shallow trenches are dug between the columns to the appropriate depth. Vertical slopes The trenches need to be made as neat as possible, since in the future they will be used as part of the formwork. The height of the beam structure can be taken 500...600 mm and correspond to the thickness of the wall. Size and manufacture of steel frames. The frames consist of 6 metal rods installed along the beam - 3 rods in the upper and lower parts.
The rods are connected to each other by bent clamps in the form of a closed loop. The dimensions of the clamps must be such that when they fit into the cross section of the beam, a gap of 25 mm remains between the reinforcement and the outer surface - a protective concrete layer that protects the reinforcement from corrosion. Manufacturing and installation of formwork. Formwork for a grillage can be made from inventory or made by yourself . The formwork is installed directly on the ground.
If a horizontal monolithic frame - a grillage - is being concreted, buried in the ground, the formwork should be 25...30 cm below the height of the beam. If the horizontal frame - grillage is raised above the surface, the height of the formwork should correspond to the mark at which the top of the beam structure should be located. After installation and fastening, sand is poured into the formwork, the upper level of which should be at the level of the bottom of the beam system (or the top of the column). Pouring concrete for the beams. Concrete is poured in the usual way, then after 5...7 days the formwork is removed.
For a high-lying structure, the sand is removed and the grillage is supported on posts. The fabrication of the supporting part of the building is completed. After another 10...15 days you can begin bricklaying.
Strip foundation with pillars in the form of bored piles
Another method is a strip foundation with pillars in the form of bored piles. Instead of holes, wells are drilled into the ground to the calculated depth, usually their diameter is 300 mm. As one support, you can use two piles installed at a distance of 40 cm from each other.
They are used as waterproofing and formwork for piles. plastic pipes or roofing material rolled into a pipe, lowered into the well, after which a frame made of reinforcement is installed, with a diameter of working rods of 18 mm. The height of the piles above the ground is determined by the manufacturing method - whether it will be a recessed horizontal frame - a grillage, or raised above the surface. Concreting of piles is carried out using conventional methods.
After construction begins, there may be a need or simply a desire to make a strip foundation from a columnar foundation. Replacing a columnar foundation with a strip foundation with your own hands is permissible if the horizontal beam part has not yet been concreted. In this case, the holes in the ground are expanded to trenches with the depth of the foundation mark and concreted. Before this, in the places where the longitudinal working reinforcement will be laid, holes with a depth of at least 15 cm are drilled, where these rods will be installed.
If replacement is planned on an already built house, such work is carried out only in cases of extreme necessity, by trained specialists who comply with all safety rules. Please note! Any excavation work near an existing house at a greater depth. than half the depth of the foundation can lead to an accident when the house or some of its parts collapses. The space between the ground and the ceiling should be open or covered with light, easily dismountable panels. This is necessary to ensure that the temperature under the house is the same as the temperature outside.
Otherwise in winter time due to frost heaving of the soil, the base may be deformed, and cracks will appear in the grillage, as well as in the enclosing structures. This can lead to an accident. Utilities, such as water supply and sewerage, which are usually brought into the house from below, must be waterproofed, since the impact of leaks on the ground can lead to a loss of the bearing capacity of the soil foundation. It is also necessary to provide utility lines with protection from freezing.
Depending on what kind of soil is located on construction site, you have to choose the right type of foundation structure. If the soil is soft, mobile, flooded or has a high level groundwater, then you can’t do without a columnar foundation. Despite the apparent simplicity of installation work, the process of constructing a columnar structure requires an accurate calculation of the load-bearing capacity of each support post. But among all types of foundations for a house, this is the cheapest in terms of material consumption, especially since it is possible to use various building materials for it. Let's look at step-by-step instructions for building a columnar foundation with your own hands.
Advantages and disadvantages of a columnar foundation
One of the advantages has already been mentioned; it is low-cost construction. You can also add to the advantages:
- quick construction of the foundation;
- there is no need to use construction equipment;
- simplicity of the work carried out, so making a columnar foundation with your own hands is not a problem;
- lack of additional measures related to thermal insulation of the foundation;
- a columnar foundation can be easily repaired;
- this type can be erected on frozen soils;
- The service life of the pillars, if the technology is strictly followed, is up to 100 years.
As for the disadvantages, there are not many of them:
- the load-bearing capacity is not very high, so it is recommended to build lightweight buildings on poles: wooden, frame, panel;
- the stability of supports is reduced if they are erected on moving soils;
- there is no possibility to organize a basement or subfloor.
Before you start making a columnar foundation with your own hands, you need to familiarize yourself with its classification, materials and carry out calculations.
General diagram of a columnar foundation
The general scheme of construction work can be outlined in several main stages. They are, in principle, no different from the construction of any type of foundation.
- The load-bearing capacity is calculated taking into account the quantity support pillars and the weight of the building.
- A general drawing of a columnar foundation is made with an exact indication of the distance between the racks, the cross-section of the supports and the height of the protrusion above the ground level.
- Conducted preparatory work: marking exactly according to plan, excavation with digging holes - wells, making reinforcing frames, adding cushions to the holes, waterproofing and installing frames. If there is a need, then the formwork of the base part is assembled.
- Making a concrete solution and pouring it into prepared wells, followed by removing air by baying the mixture. If bricks or blocks are used as the material for the columnar foundation, then they are laid.
The entire assembly of a columnar foundation is a combination of pillars with a horizontal strip, which is called a grillage. It can be concrete, metal, wood, or be the lower crown of a log house.
As you can see, there are not many positions according to the diagram, which is why it is believed that it is not difficult to build a columnar foundation with your own hands.
Classification of columnar foundations by material
Like any foundation for a house, a columnar foundation must be strong and reliable. Therefore, for its construction, building materials are used that can provide the necessary strength and reliability. These include concrete, concrete blocks, bricks, stone, metal and some types of wood, which are used in the form of logs or timber installed vertically.
The choice of material is actually a crucial moment on which the quality of the final result depends. And if the task is to build a columnar foundation with your own hands, then you need to choose the right material for its construction. For example, it is believed that monolithic structures It is better to build on water-unsaturated soils, and prefabricated blocks on damp ones.
Monolithic reinforced concrete pillars
This is the most durable and reliable design. Such a foundation has pillars high strength for tension and compression. Of course, if you take into account the correct reinforcement. Moreover, if you correctly distribute the racks along the entire perimeter of the house, taking into account the required cross-section of the supports, then multi-story buildings can be built on such a foundation.
Let us add that a columnar reinforced concrete foundation is constructed in cases where it is necessary to pour it to a sufficient depth, and more often than not, below the freezing level of the soil. It withstands soil heaving well, but is afraid of contact with groundwater. Therefore, care must be taken to waterproof the supports.
Asbestos cement pillars
Asbestos cement pipes are not often used for the construction of foundation pillars. Although they feel great in any soil. Their load-bearing capacity is not high, but it is not required, because the pipes in the foundation structure act as formwork.
Pole made of plastic pipes
The situation here is the same as with asbestos-cement. That is, plastic pipes act as formwork. They do not corrode and are not destroyed by water, so they do not require waterproofing. The only thing is that the supports need to be properly poured under the foundation. Namely: install a reinforcing frame in them and pour concrete mortar.
Made from bricks or blocks
Brick foundation pillars should be treated as the oldest known structures. From the history of European and Russian architecture, they are “long-livers”. Until now, brick pillars stand under huge buildings, and, apparently, they will stand for many more centuries. Because the choice of bricks was taken seriously in those ancient times. The highest quality burnt bricks were always used. Therefore, when building a house on a columnar foundation, this requirement must be taken into account.
As for block pillars, they are not inferior in strength to brick ones, of course, depending on the material from which the blocks are made. It is better to give preference to concrete blocks; cinder blocks in this regard cannot bear heavy loads, although they are used for light buildings such as a veranda, a bathhouse, and so on.
Block structures include pillars built from stone. Not a bad option, quite strong, but such supports cannot withstand the movements of the soil. Therefore, when building a house on a slope, it is better to abandon stone racks. As a replacement for them - foundations made of rubble concrete. This is when stones are poured into the prepared formwork, and then they are filled with concrete mortar.
Wooden pillars
Such a columnar foundation, like a brick one, has been used in Russia for a long time. Today it is not so in demand, but, for example, for bathhouses installed near a river or lake, they are often found. We must pay tribute to the correct choice of wood. The stronger it is, the longer the service life of the pillars. In this case, it is necessary to carry out protective measures very carefully.
- Treatment of the entire column with antiseptic compounds.
- Treating the part buried in the ground with bitumen mastics and gluing a layer or two of roofing material.
Doing all this yourself is not a problem, the main thing is not only to make protection, but also to install it under the pillars wooden supports in the form of a board with a thickness of at least 50 mm and a width over the entire area twice as large as the cross-section of the pillar. The support boards also need to be protected from moisture and the negative effects of the soil.
Wooden racks are mainly used for light structures. although a hundred years ago boyar mansions of several floors were built on them.
Types of columnar foundation by depth
Frost heaving is the force that is taken into account first when designing a columnar foundation. This is a very dangerous pressure, which, if not installed correctly, can tear the foundation of the house. Therefore, a large number of options for building construction are considered from the point of view of the impact of frost heaving on the foundation structure.
The basic design rule states that the foundation should be laid below the soil freezing depth by 30 - 50 cm. And if this indicator is, for example, 1.2 m, then the laying depth will be 1.5 - 1.8 m.
But often a light building cannot exert such pressure on the support posts to contain the forces of frost heaving. That is, even when laid to a great depth, the foundation will be subject to deformation. Therefore, when building a columnar foundation with your own hands, you must take into account that there are two more positions: shallow and surface.
Columnar non-buried foundation
A non-buried columnar foundation or a surface foundation are still the same racks, only their laying depth does not exceed 30 - 40 cm. Often they are simply built on the surface of the soil, having previously made a cushion and waterproofing. Designers classify this type as those foundations whose depth does not exceed a third of the soil freezing level. From our example: 120: 3 = 40 cm.
The construction of a columnar foundation of this type belongs to the category of the cheapest and most rapidly erected structures. As practice shows, they usually use a block modification using blocks, stones or bricks. But since the height of the pillars is not very large, which means their load-bearing capacity is also low, it is therefore recommended to increase the cross-sectional area of the supports. Minimum size – 40 x 40 cm.
Shallow columnar foundation
The name of a shallow foundation suggests that it is buried in the ground, but not to a great depth. In any case, not below the level of its freezing. Designers calculate the depth of their installation at the rate of 0.5-0.7 from the depth of freezing of the ground. Again from our example: 120 x 0.5 = 60 cm.
The main requirement for this design is not to touch groundwater.
Foundation with grillage
The columnar foundation unit - the grillage - has one single task - to distribute the load from the house evenly across all the pillars. As mentioned above, the grillage can be constructed of concrete, metal (channel or I-beam), wood (beam with a cross-section of 150 x 200 or 200 x 200 mm) or be a log from the first crown of a log house.
Attention! If the beam is a monolith with pillars, then during the construction of the latter, the ends of the reinforcing frame reinforcement are exposed, which are connected with a knitting wire to the reinforced belt of the grillage.
Step-by-step DIY construction instructions
Let's move on to the main question of how to properly make a columnar foundation with your own hands. The scheme of work has already been described above, where the first stage was carrying out calculations and drawing up a project. If a house is being built on a columnar foundation, then it is better to delegate this stage of construction to specialists. After all, in order to accurately make all the calculations, it is necessary to take into account a large number of different indicators and nuances. Eg:
- type of soil on the site;
- groundwater level;
- soil freezing level;
- the type of building, its number of storeys, what materials it is constructed from;
- materials from which the foundation itself is supposed to be built;
- additional loads.
Of course you can use online calculators, but not for solid houses. You can use it for baths, verandas, barns. And no one can guarantee that the calculations are 100% correct.
Marking and excavation work
So, if a building design is in hand, then the designers must link the foundation to the area. This makes it easier to find its location on the plane. Usually the reference is made to the boundaries of the site, indicating the distance from the foundation structure to these same boundaries. Therefore, before marking the pillars, it is necessary to set aside these same dimensions from the boundaries and determine the perimeter of the building.
To do this, two rows of strings are stretched along the boundaries of the building, which immediately determine the width of the foundation pillars. The rest is simple:
- the turf is removed to a depth of 20 cm;
- the installation locations of the pillars are marked: at the corners of the building and between them with the required distance, which is determined by the project;
- Using a garden or electric drill, holes are made in the ground, the depth and cross-section of which are also determined by the project.
We must pay tribute that the drawing of the columnar foundation greatly helps in marking. Because all the parameters of the future design are clearly indicated on it.
Pillow device
The cushion is a layer of sand 20-30 cm thick, which is poured into the wells and compacted using improvised means. It can be a beam, a wooden slat, or a small section of log. Often a pipe is used, to the end of which a metal plate is welded.
The purpose of the sand cushion is to divert some of the water from the supports that gets into the ground. Next, concrete mortar is poured onto the sand, which will subsequently become a support for columnar structures. The thickness of the concrete layer is 10 - 30 cm.
The formwork must be dealt with carefully, because much will depend on what kind of soil is located on the construction site.
- If the soil is clayey, that is, strong, then there is no need to make formwork as such, because the clay itself, like a monolith, does not collapse or collapse.
- If the soil is weak and sandy, then formwork will have to be installed in the well. In this case, it is necessary to take into account what shape the designers have determined: rectangular or round. If the latter, then pipes are used as formwork: plastic, asbestos-cement or metal. If the first option, then the well will have to be expanded, made of a rectangular section, and formwork made of boards or other flat materials. This is a large volume earthworks, so this form is extremely rarely used for recessed structures.
As for the first position, usually a rolled-up roofing material is placed inside the shaft. It forms the walls of the foundation and will further serve as waterproofing. Formwork made of roofing felt is a mandatory attribute.
Attention! Regardless of whether the formwork will be installed in the well or not, it is necessary to form a pillar in the base part. This means that the formwork must be assembled here.
Reinforcement
Reinforcement of pillars is mandatory, because it is the reinforcement laid in concrete that makes it possible to restrain loads from the forces of frost heaving. In the project, the number of reinforcing bars, their shape of connection into the frame and diameter must be indicated. Therefore, the reinforcement is simply cut into pieces the required length and tied into a frame. Its cross-sectional shape can be triangular, square or round. The main task of the assembly manufacturer is to correctly fold the reinforcing bars relative to each other at the required distance and clearly tie them together with wire.
After which the frame is lowered into the prepared well exactly in the middle. After which you can start pouring concrete.
Attention! The length of the reinforcement bars is trimmed taking into account that their ends will be attached to the reinforcement frame of the grillage. Therefore, the rods are cut 10-30 cm longer so that they stick out above the base part pillars
Pouring concrete
The pouring of a columnar foundation must be approached from the standpoint of standard technology. The concrete solution is made using classical technology:
- one part of cement grade M 400;
- two parts of washed sand, without a large amount of clay impurities;
- three parts of crushed stone with granules 5 - 40 mm.
The most interesting thing is that for a columnar foundation there is no need to prepare a large batch. And there is no need to fill all the pillars at once in one day, as is usually done when constructing a strip or slab structure. It is enough to calculate the volume for one column, make a batch and pour it.
For example, a pipe with a diameter of 150 mm is used as formwork, and it is installed to a depth of 1.2 m. It turns out that the volume of the empty pipe is equal to:
V = SxH, where S is the area of the pipe, and H is its length or installation depth. The area can be found using the formula: S = πD²/4=(3.14×0.15²)/4 = 0.018 m³. If converted to liters, it will be 18 liters. Essentially, these are two buckets of solution.
The pipes are filled with concrete, tapped on the formwork, and pinned to remove air. In this condition, the pillars should stand for 28 days. During this time, the concrete will gain its original strength.
Grillage arrangement
We will assume that the grillage will be monolithic according to the project. This means that under it you will have to construct formwork from any flat materials. It is done by weight, so supports made of bricks, blocks, boards, logs and other materials are installed under the lower panels. The formwork is assembled with a rectangular cross-section with complete and strong fastening of the panels to each other.
A reinforcing frame is placed inside it, usually these are two vertical gratings connected by 6 mm wire rod or 6 - 8 mm reinforcement. The reinforcement frame of the grillage must be fastened to the pieces of reinforcement protruding from the pillars. This unit of the columnar foundation is subject to serious loads, so the fastening of two reinforcement structures must be approached carefully. The concrete solution is poured with compaction and bayoneting. After 7 days the formwork is dismantled, after 28 days the foundation can be loaded.
Summarizing
As you can see, you need to approach the construction of a columnar foundation with your own hands with a thorough analysis of all stages of the construction processes being carried out. Miscalculations must not be allowed in the first place. Markings with large allowances cannot be applied. Wells must be accurately drilled to the required depth. Even a few centimeters can play a supporting role in extreme situations.
There is no need to talk about preparing concrete and pouring it. That is, the arrangement of the foundation is an integrated approach to its construction, where there is no room for mistakes and miscalculations.
Do-it-yourself columnar foundation step-by-step instructions
The technology for installing a columnar foundation with your own hands is not complicated, the main thing is to follow the step-by-step instructions, then you will have a reliable foundation
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Classmates
It is not for nothing that the construction of a classical foundation is one of the most expensive works that requires a long investment of time.
The construction process is complex - it is important to strictly follow the accepted sequence of work.
It is necessary to purchase building materials in advance and prepare the site for the foundation.
In order for the foundation to be strong and last for many years, it is necessary to pay attention to design measures that involve choosing the type of foundation, calculating loads. This stage is one of the most important. The stability of the building and the overall safety of the building depend on the quality of the project.
There are several foundation construction technologies that allow reduce labor costs. This is a device of a columnar strip foundation and its varieties. Works may vary slightly, but general principle remains the same.
Monolithic columnar strip foundation is a hybrid that combines advantages and grounds. The supports are made of reinforced concrete and pillars. on pillars differs in that several pillars rest on the ground, and not the entire tape. A reinforced concrete screed is constructed above the pillars, and as a result the strip and pillars are connected into a single structure.
Pile-tape monolithic foundation is a type of columnar-strip foundation. When constructing the structure, screw and bored piles are used. First give the base additional rigidity, which is achieved due to the presence of a screw thread. Diameter screw piles different, it is chosen taking into account the load. Installation of such supports requires special equipment, but the work can be done manually.
When installing bored piles, you first need to make a hole in the ground, and then concrete is poured into it.
To give rigidity to the structure, pipes made of steel or asbestos cement are installed in the well..
A tape is made above the piles. Once the supports are screwed into the ground, tie reinforcement onto them. Then drill holes in the top of the piles and pass the embeds through them. They are necessary to secure the reinforcement rods that will run in the longitudinal direction.
After this, you can begin to reinforce the tape frame.
Important! Carefully place the reinforcement inside the support trunk, carefully tie the upper and lower rods together. If this is not done, then after concreting the monolith will begin to crack from the inside.
Job can be done on your own.
Application
A column-and-strip foundation is erected on heaving soils. Such a foundation cannot be made for heavy buildings, but it is perfect for buildings made of foam blocks, wood and aerated concrete. The materials are light, the grillage can easily withstand them.
Pile-tape foundations are made on soft soils. It is suitable for erecting buildings on a peat bog; construction in swampy areas is possible. It is impossible to build a regular strip foundation in such areas, because the dense layer of soil is located at great depth, but the piles will reach it without difficulty; a monolithic strip foundation on piles it will turn out durable.
DIY columnar strip foundation
The construction of such a foundation consists of next stages:
1. Necessary prepare a project, which should take into account the type of building and its weight, and soil characteristics. It should.
A clear example of calculating a columnar-tape base is presented in the video below:
2. Supports must be installed in the corners of the building. The distance between the pillars should not exceed 2 m. The lower part of the supports must be widened. This will increase the supporting area and prevent the pillars from being squeezed out during frost.
3. When constructing a recessed grillage under it make a trench. If the tape will pass above the ground, you should make a concrete embankment. It must be removed after construction is completed.
4. Make formwork for supports, lay reinforcement. Pre-knit it in the shape of a parallelepiped. The dimensions of the frame should be such that when it is placed in the formwork, no more than 50 mm remains from the panel walls. Worth doing separately grillage reinforcement. Here you need to put two reinforcement belts, tying the upper and lower ones together.
5. Pour concrete into the formwork, it is best to use the M200. Concrete is poured into the wells to a depth of 30 cm, then the formwork pipe is raised. The solution spreads, resulting in an increase in the diameter of the sole.
The mixture is poured starting from the wells, then moving to other parts of the foundation. The entire solution is poured out in one go. It is necessary to release the air from the concrete - to do this, it is pierced in several places. After this, the solution is compacted, resulting in the appearance of cement laitance.
6. When the concrete hardens, remove the formwork.
7. Grillage cover with waterproofing material.
Monolithic screed
A column-and-strip foundation with a monolithic screed is often used in construction. The screed is called a grillage. The only difference between a grillage and a conventional strip foundation is that it rests on pillars rather than on the ground.
Important: The type of screed depends on the type of soil. If it is slightly heaving, then it can be buried 0.5 m into the ground. Heaving soils require a different approach. In this case, the screed should be made above the ground - there should be a gap between it and the grillage.
How to lower protruding pillars under the foundation strip?
In this case, you can proceed in two ways. Each of them will require significant financial investments.
The first assumes installation of a pile-screw foundation near the old one, after which metal channels are installed under the building, which will rest on piles.
The second option involves strengthening the foundation. Dig trenches under all support points, and then refill the foundation with reinforcement. The result will be a massive base. Since its weight will be large, it will be impossible to squeeze it out.
Advantages and disadvantages
The construction of a foundation on piles or pillars has the following pros:
- high speed of construction and small volume of earthworks;
- fairly low cost;
- possibility of construction on highly heaving and peaty soils;
- does not require special equipment or hiring professional builders.
- suitable for country house and garage construction;
- there is no need to pour cushions of crushed stone and sand under the entire base;
- no drainage system required;
- low consumption of concrete and other building materials;
- reduction of heat loss;
- vibration isolation of the building.
TO shortcomings it can be attributed to the fact that such a foundation is not suitable for brick houses. Much depends on the location: in regions with harsh climates it will be necessary additional insulation plinth.
Useful video
Additional information on how a monolithic screed is made: strip foundation and design features is presented in the video below:
conclusions
A column-and-strip foundation can be erected for buildings whose walls are made of lightweight materials. Before starting construction, a project should be prepared. Base structure will not require large financial expenses, all work can be done on your own.
In contact with
The foundation of the building under construction must be strong and reliable, able to withstand all weight loads from the building structures of the house, engineering equipment, household items and snowfall on the roof. The foundation must remain stable in the event of possible soil movements and not collapse in the event of freezing or rising groundwater. However, erecting a heavy and powerful reinforced concrete foundation is not always advisable. In certain cases, the issue of reliability can be solved by using a supporting structure of a columnar-tape type.
This is a kind of combined strip-column foundation, which simultaneously combines technical solutions adopted for pile and strip monolithic systems.
Thanks to this, such foundations can be erected on weak, unstable soils with a high groundwater level and a large freezing depth for one-story residential buildings and outbuildings. Strip foundations can be built for wooden and frame buildings that do not have heavy reinforced concrete floors and stone walls.
Brief description of the design
Structurally, the columnar-strip foundation consists of several supporting stone pillars, on which rests a reinforced concrete shallow grillage, which takes all the weight loads of the building. Reinforced concrete pillars, poured on site, are most often used as pole supports.
In general, the columnar-ribbon base combines the following main elements:
- reinforced concrete pillars, the design and quantity of which are determined by calculation;
- reinforcing frame filled with concrete;
- above-ground strip structure made of bricks or blocks;
- internal vertical supports for bearing loads for walls and partitions.
Upon closer examination, you will notice that the very idea of the technology was taken from multi-story city buildings with basements and semi-basements, where a pile field of the design configuration is driven in, and after that a binder is installed strip grillage a small recess to create a single support.
Advantages and disadvantages of column-and-ribbon structures
The construction of this type of foundation is less labor-intensive than with any other type monolithic reinforced concrete, and also requires less construction materials. Having in hand design solutions, to perform the work you will not need professional construction knowledge and extensive experience. Even a beginner can cope with this, having one or two assistants with him.
TO design advantages Columnar-ribbon bases can be classified as:
- good protection from vibration effects and possible ground movements;
- special design of support pillars, which increases strength and stability;
- the use of mixed types of materials when installing the grillage;
- increased thermal insulation properties due to the lack of contact of the underground floor with the soil;
- the possibility of construction in areas with difficult terrain without preliminary planning;
- reduction in the volume of earthworks;
- the opportunity to make a columnar strip foundation with your own hands.
In addition to obvious advantages, such support structures also have disadvantages that can somewhat complicate the organization and implementation of work:
- complex engineering calculations that take into account a combination of soil characteristics and the total weight load;
- possible differences in the cross-section of the support along the height and perimeter of the building;
- the practical impossibility of determining the influence of soil heaving, which requires a safety margin;
- impossibility of making a basement.
Therefore, it is recommended to entrust the calculations and project development to professionals who will determine the necessary data and make decisions with the minimum possible, but necessary margin of safety and reliability.
Selection of support pillar material
The reliability of the foundation structure largely depends on the right choice support strut material. At this stage of construction, you should not try to save money. If at the moment the purchase of inexpensive materials will allow you to save certain cash, then in the future very significant sums will have to be spent on repairs and correction of defects.
For the construction of a columnar strip foundation with monolithic slab ceilings can be used:
- wood;
- rubble stone;
- solid red brick;
- aerated concrete, foam blocks, slag concrete or concrete blocks;
- asbestos-cement, concrete, plastic or metal pipes;
- concrete pillars;
- pre-fabricated and bored columns.
Each material has its own characteristics, which are described below.
Wood
The main reason for the low popularity of wooden foundations is their fragility. Even additional treatment to protect against moisture, rot and insects increases the service life for a short time. However, wooden beams can be used to construct grillages raised above the ground in the construction of light utility and domestic buildings.
Rubble stone
This material has long been known to builders and has been widely used for the construction of foundation structures. It is distinguished by great strength and durability. However, its laying requires highly skilled mason skills to fit individual stones to each other. Therefore, only a professional builder can lay reliable rubble stone pillars.
Types of columnar foundations: a. brick pillar on a rubble base; b. solid brick pillar; V. brick pillar on concrete base; d. burnt wooden chair (oak or pine); d. metal stand; e. rubble pillar. Bricks and blocks
For the underground part of the foundation structure, you can only use clinker or solid clay brick high brands. In columnar strip foundations made of bricks and blocks, the above-ground part of the grillage is laid out, located on a concrete monolith.
Given the hygroscopicity of these materials, a surface coating device is required bitumen waterproofing in several layers.
Pipes
The use of asbestos-cement, concrete, plastic or metal pipes suitable as permanent formwork, inside which it is installed reinforcement cage and concrete is poured. As a result, you can quickly obtain reinforced concrete pillars High Quality. Metal materials must be provided with a waterproofing coating to protect against corrosion.
Concrete pillars
Vertical pillar supports made of reinforced concrete are made on site after drilling or excavating wells. The structures are poured inside removable or permanent formwork after installing the reinforcement cage. In addition, individual poles or prefabricated piles can be purchased. They are installed at points with the greatest weight load and then tied with a grillage.
Rammed and bored posts
They are purchased ready-made on the building materials market. Installation is carried out using special driving equipment directly at the installation sites. Structurally, these are hollow reinforced concrete supports, inside of which a metal frame is installed and concrete is poured. Columns of both structures may be used together.
Technological principles of construction
The entire foundation construction process must be carried out step by step, in the following order:
- installation or installation of support pillars;
- installation of reinforced concrete monolithic screed, metal or wooden grillage;
- brick or block masonry.
This division is based on the possibility of continuous production of work at each of these stages.
Installation of support pillars
Calculation of the cross-section, quantity, locations and depth of pillar supports. When choosing the type of structure, it is recommended to use a shallow monolithic grillage strip located along the pillars to a depth of about 500 mm.
This allows the weight load from the building to be more evenly distributed on the foundation. A grillage structure raised above the ground should be done in the presence of complex terrain, in places of strong soil heaving and in permafrost areas.
The sole needs to be buried 300-400 mm lower possible point soil freezing, taken from SNiP “Climatology”. Based on the results of engineering calculations, depending on the selected material and terrain features, specifications pillars such as diameters, locations and installation method.
Reinforcing frames must contain at least 4 vertical strings. Myself technological process Installation of supports can also be divided into several sequential works, which include:
- removal of existing vegetation and leveling of the work site;
- marking the locations of pillars and grillage configurations;
- drilling or digging wells;
- installing a sand cushion and pouring concrete only to the height of the lower base plate;
- ensuring waterproofing protection of elements;
- installation of permanent formwork or bored columns;
- assembly and installation of reinforcement cages;
- pouring concrete into formwork or columns.
When pouring, one should take into account the mandatory expansion of the base to a size twice the diameter of the column itself, but not less than 400 mm. Therefore, concrete pouring should be done in two stages. Initially, you should fill the base, wait 2-3 days, and only then begin installing the formwork for the installation of supports.
Grillage installation
With a shallow grillage design, this stage of work should begin with digging a trench from the very beginning. The depth of the concrete strip should be more than 400 mm.
After this, the formwork of the design configuration is installed. To do this, you can use boards or standard factory-made shields. Inside the assembled formwork it is necessary to lay a layer of plastic film or roofing felt. This will ensure the tightness of the structure and prevent water leakage from the cement mixture.
Are being manufactured metal frames according to the design design diagram for the installation of a horizontal reinforcing belt. All reinforcement structures are placed inside the formwork and, during installation, are connected in conjunction with the vertical strings of the pillars, which must protrude to a height of at least 300 mm.
Correct and incorrect device. Next, you can start pouring concrete. The mixture must be laid in layers, and the work is planned in such a way that the laying of the concrete mixture is completed in a day. The above-ground part of the foundation can be made of bricks or blocks. This will ensure the presence of a horizontal waterproofing layer between underground part and the supporting tape of the layer of construction of the walls of the house.
The formwork can be removed a few days after the concrete has gained strength.
At the final stage, all outer surfaces of the grillage are covered with three layers or rolled materials. Protecting stone structures from moisture at each stage of work will ensure long-term operation and prevent the formation of destruction.
Installation sequence. Foundation Construction Guide
Let's summarize. Step-by-step instruction Do-it-yourself installation of a columnar strip foundation involves performing the following stages of work:
- Clearing the site of trees, bushes and low vegetation. Leveling the ground surface if necessary.
- Marking the installation locations of pillars and grillage contours along the axes of the house. The pillars must be in all corners of the building and at a distance of no more than 2.0 meters from each other.
- For brick, rubble or square monolithic pillars, you need to dig holes. For permanent cylindrical formwork in the form of pipes or hollow columns, holes should be drilled. The depth of pits or wells is 300 mm deeper than the possible freezing point.
- Pour and compact sand or crushed stone-sand cushion into the open cavities. Install formwork elements or bored posts. Raise them above the bottom of the pit to the height of the support cushion.
- After this, install the reinforcement frame of the columns, resting on the bottom, and pour concrete to the height of the support pad. Wait 2-3 days for the concrete mixture to set.
- Pour concrete into the column formwork and compact it well using a vibrating tool. After hardening the concrete mixture at removable formwork or masonry, treat the surfaces with a triple layer of bitumen coating insulation. This work can be performed after installing the grillage.
- Install the formwork in such a way that the reinforcement protruding from the pillars fits into its internal space. Next, begin assembling the formwork for the horizontal belt. After installation, close the walls and bottom plastic film or roofing felt.
- Assemble the reinforcement cage in accordance with the design and lay it inside the formwork structure. After this, tie or weld a horizontal belt with the vertical strings of the pillars.
- Concrete is poured into the grillage formwork in one day. Concrete is laid in layers and the mixture is compacted to remove air bubbles.
- If masonry is used in the construction of the foundation grillage, then 2 layers of roofing material should be laid over the concrete surface to create a waterproofing layer. Every 3-5 rows brickwork needs to be reinforced metal mesh with a cell no more than 100x100 mm made of 5-6 mm wire.
5-7 days after completion of the work, you can begin installing the walls or frame structure of the building. In the case of a raised grillage structure, all sand located under the building must be removed. In this case, the house will remain supported only by columns.
Video on the topic
The foundation is the foundation of the entire building, so it is very important that it is strong and durable. A strip-and-column foundation is a monolithic type of foundation, which is ideal for erecting it on heaving, swampy or sandy soil. This type of structure is suitable for private houses with wooden or timber-frame walls. It is quite durable and does not require significant costs. This article will talk about how to make a strip-column foundation with your own hands, without using special equipment and without hiring highly qualified workers.
This type of foundation consists of two main components - supporting structures and grillage. The supporting structures are pillars, and the grillage is a system in the form of a tape.
The strip element allows you to cover the subfloor of the building with a reliable structure that allows you to withstand excess humidity. In addition, the grillage tape creates a surface that is very convenient to use for laying such wall materials, like foam blocks and bricks.
Advantages of a column-strip foundation
The advantage of this type of foundation is the presence of vibration protection. The structural support is equipped with side sections that are tightly fastened to the tape element, which creates a “vibration isolating system.” The main purpose of this system is to reduce the effects of vibration generated from automobile or railways located next to the building.
The main positive quality of this type of foundation is its low labor intensity. Even non-professionals can manipulate the preparation of a site for construction and pouring the structure with concrete, so it’s quite easy to make a columnar strip foundation with your own hands. The strip element of the foundation structure is placed above the ground, so the amount of concrete mixture used is reduced, which allows for significant savings on the construction budget.
In addition, another advantage of this design is low heat loss. This quality is explained by the fact that the main part of the structure will not have contact with frozen soil, which will reduce heat loss by approximately half.
Components of a columnar strip foundation:
- The supporting structure is pillars. The number of pillars depends on the weight of the building.
- Reinforcing frame.
- Tape design.
- Internal piles.
Types of pillars for columnar-strip foundations
Precast pillars are produced directly at the construction site and installed in special wells into which concrete mortar is poured. Bored posts are especially popular. This can be explained by the fact that this design does not require special costs and has good load-bearing capacity. This type of structure can be concreted without casing.
In some cases, single support structures are used. Such poles are suitable for places that will bear the main load.
Choosing the right material for constructing the pillars of the structure
When constructing a strip-column foundation, you first need to pay attention to what materials will be used in the construction of the supports. For this purpose, you can use brick, concrete blocks, metal or asbestos cement pipes, as well as wood.
Peculiarities: 
- Wooden supports. This type of pole is not particularly popular due to the fact that wood is a short-lived material. But still wooden supports are used for construction. wooden terraces. The pillars for this purpose should have a diameter of 0.15 -0.2 m. In addition, it is better to treat the wood with impregnations that will prevent destruction.
- Pillars made of pipes made of asbestos concrete or metal. Monolithic columnar-strip foundations are quite often made from these elements, since such pipes are well suited for permanent formwork.
- Brick pillars. Supports made of this material are used if the columnar foundation is to be made unburdened. The width of the brick structures should be half a meter.
- Concrete pillars. This type of support is considered the most reliable, therefore they are most often used in self-construction columnar strip foundation. There are monolithic concrete pillars and those made from ready-made blocks. The width of this structure should not be less than half a meter.
The process of constructing a columnar strip foundation
This process consists of two main stages:
- Creation supporting structure from pillars.
The first step is to choose the right foundation depth. This must be done taking into account the structure of the soil, the degree of freezing of the ground and the depth of groundwater. As the foundation sinks, it is divided into two types: shallow and buried. The buried column-and-strip foundation is immersed approximately half a meter below the freezing level of the soil.
You need to pay attention to the fact that the pillars need to be installed at a distance of one to two meters from each other. A larger distance may result in a structure that is not very strong.
The installation of foundation supports must begin with the preparatory stage, which consists of preparing the site for construction. First of all, remove the excess layer of soil, making the area level. If the soil at the construction site is clayey, then you need to remove most of it and fill the area with sand.
Then we mark out our construction site. To do this, you need to use a special thread used in construction. Let's stretch it in the form of two non-intersecting strips, the distance between which is equal to the thickness of our strip foundation.
Do not forget to monitor the angle of intersection of the threads, it should be equal to 90⁰. Also, we must not forget to mark the intersections of wall surfaces and the corners of the building.
The next step is to dig trenches in the places where the strip structure of our foundation lies. The depth of the trenches should be approximately 40 cm, and the width should be made in such a way that there is still about 10 cm left for placing the formwork.
To install the pillars we use a concrete mixture, but do not forget about creating a waterproofing layer. For it, using roofing felt rolled into a couple of layers, we make a pipe. We connect it with tape and insert this structure into the ground until it stops.
Before making a columnar strip foundation, you need to take care of creating a frame from reinforcement and wire, and then insert it into the drilled hole so that the reinforcement protrudes outward by approximately 15-20 cm.
Next, we will begin pouring the resulting support with concrete. To begin, we will pour a layer of concrete mixture about 20 cm thick into the well. Then we will lift the roofing felt pipe to allow the mixture to form a base. The next step is to fill the well completely and leave the concrete to dry.
- Creation of the strip part of the foundation.
First of all, we knit the reinforcing frame again. Then we weld it and attach it to the reinforcement protruding from the concrete-filled pillars.
Having completed all the above-described stages of constructing a columnar-strip foundation, we will begin installing the formwork, which is part of the strip foundation. To do this, take several boards, the width of which is 10 cm, and assemble formwork from them. Then lay waterproofing inside the formwork, which can be polyethylene film.
After carrying out these manipulations, we will fill the formwork with concrete. You can do this manually, or you can use a special mixer machine. The formwork can be removed after three weeks, when the concrete becomes strong.
After the concrete has hardened, you need to apply a coating layer of waterproofing to the foundation. The side parts of the strip structure need to be processed. For this purpose, heated bitumen can be used. It is best to do this procedure a couple of times.
It is better to remove the sand poured under the strip element, since otherwise the building will stand on a non-buried structure. The result should be a trench about two centimeters deep. After pouring the concrete, the mixture that falls into this trench will create a protrusion that will help securely fix the structure.