How to make a formwork for the foundation: types, materials, calculation, do-it-yourself installation work. How to make a removable formwork for the foundation of a house The best formwork for the foundation

The main requirement for formwork for a strip foundation is that it must be rigid and strong so that the zero-level shape is ideal. That is why the formwork geometry deviations cannot be more than 2 mm and there can be gaps in the joints between boards and panels no more than 2 mm - all this can be easily controlled with a two-meter rail. So, the formwork device for the foundation and its types - this article will tell about all the subtleties and nuances.

Traditional simple technology

For a strip foundation, the formwork is installed as follows: guide boards are placed and fixed with pegs that are hammered into the ground. Then, shields are placed on one side of the foundation - so that their plane completely coincides with the edge of the board.

The shields are fixed with braces, in a strictly vertical position. And then shields are placed on the other side of the foundation, and here it is extremely important to observe its internal dimensions.

Further, the shields are fastened with spacers and additional clamps every half a meter-meter, which will not allow the formwork to open when pouring concrete. Outside, they can be fixed with the same struts, spacers or pegs. All this is a removable formwork for the foundation.

The formwork for the strip foundation is traditionally built from boards and boards of hardwood and coniferous species, the humidity of which does not exceed 22%. That is, it is the same moisture-resistant plywood, chipboard and fiberboard. And in order for the temperature and humidity conditions to be optimal, the entire inner surface of the formwork is often lined with plastic wrap - it is easy to attach it to the boards with an ordinary furniture stapler. So the solution will not leave through the cracks, and the whole mixture will harden quickly and efficiently.

The most budget formwork option - and more than once

How to make formwork for the foundation from improvised materials? Easily! It can even be made of plywood - cheap and cheerful. It is necessary to fasten its sheets together with self-tapping screws and steel corners. But the joints - close with strips of thinner plywood, on self-tapping screws. Holes for ties in it must be made horizontally in increments of 550 mm, 50 mm vertically and 250 mm from the top.

Supports here need to be placed only in places - in order to align the formwork vertically. But for the longest sections of the foundation, in order to achieve straightness, a steel rectangular pipe 25x60 mm is screwed with an edge along the very top of the plywood.

Plastic formwork for the foundation is also popular today - and it is not expensive.

Fixed formwork option

Fixed formwork is much easier to install than traditional formwork - everyone who could only was convinced of this. But, besides this advantage, such a formwork has a number of undeniable advantages - and the most important of them is that the fixed formwork itself also creates a heat-insulating layer for the foundation. And yes, you don't have to take it off.

So, what is a fixed formwork for the foundation? These are plates or blocks made of expanded polystyrene. They are distinguished by increased density, and are attached to each other with special jumpers, while the perimeter part has locking grooves. The weight of one such element reaches only one and a half kilograms. And the concrete mixture will not leak anywhere during the pouring process - the tightness of such joints is high.

No supporting elements are needed here - this is another fairly significant plus. In addition, such formwork makes it easy to ensure the correctness of the geometric shapes of any foundation - even a complex structure with steps. But special grooves are placed from the inside of the formwork slabs - they help the concrete mix to effectively adhere to the wall surfaces. In total, such a protective structure consists of three layers - and it is installed in one production cycle. The base materials are well protected, thermally insulated and cannot be destroyed by either external atmospheric phenomena or water. This is both waterproofing and protection against fungus - after all, such blocks perfectly cope with any destructive organisms, due to which there can be neither rot nor mold on such a foundation. And such a foundation has been serving for more than 80 years - and this is not the limit.

As a result, the entire production of the tape turns out to be extremely simple - concrete is poured between the formwork slabs and, if necessary, reinforced in advance. And after the concrete mixture hardens, the formwork for the expanded polystyrene foundation is no longer removed - they will protect the foundation from heat loss for many decades to come. And most importantly, even the most distant person from construction can easily build such a foundation - everything is so simple that it reminds many of an ordinary children's designer.

The only thing that needs to be done is to create a good drainage system in the bath. And without any problems, a ventilation system is created inside such a foundation, and pipelines and electrical wiring are laid.

As a result, the foundation for the bath turns out to be warm, protected and economical - special studies have shown that expanded polystyrene formwork speeds up construction work by one and a half times, its labor intensity is reduced by 40%, and 25% is less than the estimated cost of building a zero level. For your favorite bath, this option is ideal.

Around any building, or rather along its perimeter, a blind area is necessarily arranged. This coating protects the building from the destructive effects of melt and sedimentary waters, which can wash away the soil under the base of the house and lead to its subsidence, as well as destroy the foundation structures. This important protective element around the house is made of concrete or asphalt concrete. In order to complete the blind area, you need to build a formwork. At first glance, this is not difficult to do, but there are some nuances that must be observed so that the blind area has the correct slope from the walls of the building. In our article we will tell you how to make formwork around the house.

Features and functions of the blind area

Outwardly, the blind area looks like an ordinary concrete or asphalt path, which tightly adjoins the walls of the building and surrounds it around the perimeter. The width of this coating is normalized by SNiP and can be at least 1 m. At the same time, it is worth remembering that the outer edge of the blind area should protrude beyond the boundaries of the roof overhang by at least 200-300 mm.

Important: the installation of this protective coating is carried out after finishing facade work has been done on the house.

The blind area performs several functions at once:

During snowmelt or rainfall, precipitation can soak into the ground near the house and cause the destruction of foundation structures or flooding of the basement. Much more precipitation collects around the house, as it actively drains from the roof of the building and its walls.
Due to the blind area, the soil around the building does not freeze to such a great depth as in places of open soil. Thanks to this, the basement or basement becomes warmer, which affects the temperature throughout the house.
In addition, frozen soil can also adversely affect foundation structures. This path near the building protects building structures from the forces of frost heaving, which can lead to movement of the base and cracking of the walls of the building.
The presence of a neat blind area around the house increases its aesthetic qualities.

The following materials can be used to make this coating:

Concrete is the most commonly used because it is the most affordable material that you can prepare yourself. For pouring concrete, you need to properly equip the formwork. That is why in our article we will consider the subtleties of this process.
You can also make a blind area from paving slabs.
Around large public, multi-apartment residential buildings and shopping centers, the blind area is made of asphalt.

Rules for the execution of formwork and blind areas

Before you get to work and start making formwork near the house with your own hands, you should remember a few simple rules that will allow you to do everything at the highest level:

If the work will be carried out in hot weather, then the surface of the formwork and concrete (after pouring it) must be periodically moistened with water. Due to this, dried wood will not absorb moisture from concrete, thereby reducing its strength. Wetting and covering the concrete cover in the first few days after pouring will avoid too rapid and uneven evaporation of moisture, which can lead to cracking of the surface.
In order to correctly determine the width of the blind area, the slope, the depth of its laying and design, it is important to take into account the geological and climatic features of the construction site. By following this rule, you will make a high-quality and durable blind area.
The arrangement of this coating around the building is best done before the onset of cold weather.
This protective concrete product should encircle the entire house with a continuous strip. That is, the coating should not have gaps and areas of unprotected soil. Otherwise, through such uncoated gaps, water will easily seep into the ground and cause the destruction of the foundation structures.
A deformation seam is necessarily made between the blind area and the basement of the house, since these structural parts cannot be connected to each other. The width of the temperature gap is 2 cm. The seam must be closed with a sealant so that water does not seep into it.
The slope of the coating must be at least 10 ppm from the walls of the house, that is, 1 cm of slope per meter of width.

Necessary materials

unedged or edged board;
shield formwork can be made of chipboard (chipboard);
moisture-resistant plywood or oriented strand board (OSB) is also suitable for these purposes;
some types of formwork that take heavy loads are made of steel and aluminum alloys;
fixed formwork is made of expanded polystyrene reinforced with fiber additives.

To perform the formwork of the blind area, an unedged board or plywood sawn in strips is suitable. Since the poured concrete can slightly expand the formwork structures, bars with a section of 30x30 are used as supports and a supporting frame, from which a solid structure is made.

Important: for the manufacture of a protective coating around the house, a removable formwork is usually used, which is dismantled after the concrete has hardened.

It is equally important to correctly determine the material for the manufacture of the blind area. The coating can be made of rammed gravel, but in this case it is necessary to equip a good drain from the roof so that the flowing precipitation does not erode the fragile gravel coating.

A little better and more durable than crushed stone coatings will be a cement mortar pavement laid on top of rammed gravel. This option provides better protection of the base of the house from destruction by melt and sedimentary waters. And it is this option for arranging the blind area that provides for the execution of formwork.

A more expensive and high-quality version of the blind area is the laying of monolithic concrete slabs or reinforced slab products. But such materials cannot be used on heaving and clayey soils, as well as at high groundwater levels, since the structure can quickly deform.

In the case of a concrete blind area, you will need the following tools and materials for work:

crushed stone, sand and cement;
polyurethane sealant for insulation of expansion joints between the coating and the house;
reinforcing mesh;
nails, screws;
roofing felt or polyethylene film;
edged (unedged) boards or strips of plywood along the height of the poured coating;
level, rule;
spatula, bayonet shovel;
container for mixing concrete.

Formwork technology

After you decide on the material for the blind area, calculate its width and the required slope, you can get to work:

First of all, it is necessary to mark the future coverage around the house. To do this, the estimated distance recedes from the walls, pegs are hammered in the corners and a fishing line or cord is pulled.
After that, within the markings along the perimeter of the building, a fertile layer of soil 20 cm thick is removed. The soil at the bottom of the resulting recess is carefully leveled and rammed.
Now proceed to the assembly of the formwork. First, a frame is made from a bar. To do this, at the corners of the recess in the soil, bars are fixed with a height slightly higher than the thickness of the coating being performed. Further along the stretched fishing line, the same bars are installed in increments of 50-100 cm. For greater rigidity, the bars are fastened together with longitudinal bars. Wooden elements are connected with nails or self-tapping screws.
After that, we attach an unedged or edged board to the frame from the timber so that the timber is on the outside of the structure, that is, on the side of the concrete pouring there is a continuous flat surface of the boards. We fasten the boards to the frame with nails.

Attention: so that concrete cannot seep between the boards, the gaps between adjacent elements should not be more than 0.3 cm.

So that after pouring concrete, the formwork structure does not burst and deform, oblique struts are attached to the frame from the outside. The installation step of such spacers is 50 cm. We fasten the spacers to the frame bars using self-tapping screws or nails.
To make it easier to remove the formwork after pouring and hardening of concrete, its inner surface can be covered with a dense plastic film or one layer of roofing material. This material will perform other additional functions:
- will not allow moisture from concrete to be absorbed into the formwork boards, thereby reducing the strength of the concrete coating;
- if there are significant gaps between the formwork boards (especially if unedged boards are used), the coating will prevent concrete from flowing into the gaps.

Along the walls of the house, it is necessary to install an edged board 2 cm thick and slightly higher than the height of the coating in this place. It is not necessary to firmly fix the board, because after the concrete hardens, it will be removed. With the help of this board, we will create the necessary temperature gap between the coating and the walls of the house.

Covering

After the formwork is assembled, you can start making concrete pavement around the house. In this case, the following sequence of actions is followed:

First, a sand cushion 10 cm high is made. The sand layer is leveled, wetted with water and rammed.
After that, a layer of crushed stone 10-15 cm high is made. It is also carefully rammed. At the same time, one should not forget about the necessary slope of the blind area from the walls of the building, therefore, already at the stage of performing the crushed stone cushion, you can take care of creating a slope.
A reinforcing mesh is laid over the rubble.
Now you can start pouring the concrete solution. You can use a factory mix or make your own.

Important: in order for the coating to have a sufficiently high strength and not crack over time, concrete must be poured at a time, without long interruptions in work.

The mortar to be poured must be thick enough so that it can be laid in a thicker layer against the walls of the house, thereby creating the necessary slope. The correctness of the filling is checked using a level. The surface is leveled by the rule.
In the process of hardening in the first days, the concrete surface is wetted with water and covered with a plastic film.
After removing the formwork and removing the board, which is laid along the walls of the house, the formed temperature gap is filled with polyurethane sealant.

An important stage in the construction of the foundation is the formwork. Formwork is a form into which concrete is poured, it is installed immediately after the preparation of the site and the trench for the foundation. The article will tell you how to make the formwork for the foundation.

Formwork can be removable and fixed. Fixed formwork is performed when no material is required to be removed from the foundation surface. An example is fiberglass or polystyrene board shields, often used for - they also serve as insulation.

In private construction, a strip foundation is usually used; for its construction, removable formwork is used from ready-made metal shields, plywood or boards. The requirements for it are very high:

The formwork must be strong enough to withstand the pressure of the concrete on the walls;
Formwork dimensions must be strictly observed;
It should not have cracks through which the solution can flow;
The fastening of the elements is carried out in such a way that the formwork can be dismantled with a frozen foundation.

Purchased metal shields have high strength and a smooth surface, they are easily attached with a bolted connection and quickly removed from the finished foundation, leaving a smooth and even surface. However, they have one drawback - the price. For developers building dozens of houses per season, the cost of purchasing shields is justified, but when building a foundation with your own hands, it is more expedient to assemble a plank or plywood formwork.

Plank formwork device

Do-it-yourself formwork made of boards or plywood is a shield on a frame made of bars, which are fastened together into a single structure. Shields are strengthened with ties, slopes and clamps. The shields are installed in the prepared trench so that all the fasteners are on the outside, and on the inside a smooth and maximally flat surface of the required shape is obtained.

For collapsible formwork, an edged board is suitable, it can be of the second grade, or birch plywood. The thickness of the material is from 10 mm. The frame of the shields is assembled from a bar 40x60 mm. Cuts, clamps and ties can be made from any materials at hand, usually the remains of boards or a bar are used for this purpose. The main thing is to ensure sufficient strength and high-quality fix them.

The inner surface of the formwork from a non-planed board will not be smooth enough, but if you are planning to insulate the foundation or its external finish, this circumstance will rather be beneficial - plaster mortar and glue fit much better on a slightly rough surface.

Technology for making formwork from boards or plywood

Prepare material for shields. The bars are cut into equal segments, half a meter longer than the height of the foundation. One side of the bars is sharpened - with their help, the shields are driven into the ground. Boards or plywood are also cut to the size of the shields. The boards are carefully adjusted so as not to leave gaps. The thickness of the material is chosen depending on the size of the foundation and, accordingly, the thickness of the concrete, which will put pressure on the formwork. In most cases, boards with a thickness of 24-36 mm are sufficient.
Spread the bars on a flat surface at a distance of one meter, align them along the upper edge, put boards or plywood on top and fix them with nails or self-tapping screws. The head of the fasteners must be located precisely on the inside of the shield, otherwise the protruding tip of the nail or self-tapping screw will seriously complicate the removal of the formwork.
When making a foundation with an expansion in the lower part, the shields rest against the support board, while there is no need to stick them into the ground, and the bar is cut to the width of the shield.
Mark the site by pulling a nylon twine between the bars driven into the ground. According to the marking, they dig a trench of the required depth, perform sand and gravel backfill.
Install the support board if necessary, and after it - the shields, fixing them to the board or driving the pointed part into the ground. At the same time, a plumb line and a level are used, achieving the most even position of the shields.
Between themselves, the shields are fastened with the help of sections of the board, nailing them from the outside to the bars of the shields. The sides of the formwork are fastened with clamps - U-shaped structures made of bar or boards that do not allow the sides of the formwork to diverge when pouring concrete. The corners are additionally fastened with boards, fixing them to self-tapping screws.
If the shields are not stable enough, they are also fixed with spacers from the bar segments from the inside and the slopes from the outside. The slopes are a bar cut at an angle of 45 degrees and set at a distance between the soil and the shield.
The bottom and walls of the formwork from the boards are lined with a dense plastic film to avoid seepage of the mortar and premature evaporation of cement laitance.
Installed from a bar and. The surface is leveled, covered with a film and kept until the concrete sets.
Formwork can be removed when a small gap appears between the boards and the concrete foundation. When removing the panels, it is necessary to lightly tap them from the outside with a rubber mallet, this will allow you to remove the formwork with the least effort. First, screeds, mowings, clamps are removed. After that, the shields are removed one by one.
If a film was used, it can not be removed from the surface of the foundation until it is completely dry - this will prevent premature drying of the top layer and allow the concrete to gain maximum strength.

Formwork boards made of plywood and planks can be reused many times, and to facilitate their removal, it is better to line the formwork with foil each time. The formwork can also be combined - this type of formwork is often used in loose soils when making or buried foundations. In this case, the underground part is made of non-removable asbestos-cement pipes or polystyrene sheets, and the above-ground part is removable, made of boards or plywood.

Video - how to make a formwork for the foundation

Features and functions of the blind area

Important: the installation of this protective coating is carried out after finishing facade work has been done on the house.

The blind area performs several functions at once:

During snowmelt or rainfall, precipitation can soak into the ground near the house and cause the destruction of foundation structures or flooding of the basement. Much more precipitation collects around the house, as it actively drains from the roof of the building and its walls.
Due to the blind area, the soil around the building does not freeze to such a great depth as in places of open soil. Thanks to this, the basement or basement becomes warmer, which affects the temperature throughout the house.
In addition, frozen soil can also adversely affect foundation structures. This path near the building protects building structures from the forces of frost heaving, which can lead to movement of the base and cracking of the walls of the building.
The presence of a neat blind area around the house increases its aesthetic qualities.

The following materials can be used to make this coating:

Concrete is the most commonly used because it is the most affordable material that you can prepare yourself. For pouring concrete, you need to properly equip the formwork. That is why in our article we will consider the subtleties of this process.
You can also make a blind area from paving slabs.
Around large public, multi-apartment residential buildings and shopping centers, the blind area is made of asphalt.

Rules for the execution of formwork and blind areas

Before you get to work and start making formwork near the house with your own hands, you should remember a few simple rules that will allow you to do everything at the highest level:

If the work will be carried out in hot weather, then the surface of the formwork and concrete (after pouring it) must be periodically moistened with water. Due to this, dried wood will not absorb moisture from concrete, thereby reducing its strength. Wetting and covering the concrete cover in the first few days after pouring will avoid too rapid and uneven evaporation of moisture, which can lead to cracking of the surface.
In order to correctly determine the width of the blind area, the slope, the depth of its laying and design, it is important to take into account the geological and climatic features of the construction site. By following this rule, you will make a high-quality and durable blind area.
The arrangement of this coating around the building is best done before the onset of cold weather.
This protective concrete product should encircle the entire house with a continuous strip. That is, the coating should not have gaps and areas of unprotected soil. Otherwise, through such uncoated gaps, water will easily seep into the ground and cause the destruction of the foundation structures.
A deformation seam is necessarily made between the blind area and the basement of the house, since these structural parts cannot be connected to each other. The width of the temperature gap is 2 cm. The seam must be closed with a sealant so that water does not seep into it.
When making formwork, it is worth making sure that there are no significant gaps in its structure through which uncured concrete mixture can flow.
The slope of the coating must be at least 10 ppm from the walls of the house, that is, 1 cm of slope per meter of width.

Necessary materials

For the manufacture of formwork, you can use different materials, which are selected depending on the complexity of the design and its purpose:

unedged or edged board;
shield formwork can be made of chipboard (chipboard);
moisture-resistant plywood or oriented strand board (OSB) is also suitable for these purposes;
some types of formwork that take heavy loads are made of steel and aluminum alloys;
fixed formwork is made of expanded polystyrene reinforced with fiber additives.

Important: for the manufacture of a protective coating around the house, a removable formwork is usually used, which is dismantled after the concrete has hardened.

In the case of a concrete blind area, you will need the following tools and materials for work:

crushed stone, sand and cement;
polyurethane sealant for insulation of expansion joints between the coating and the house;
reinforcing mesh;
nails, screws;
roofing felt or polyethylene film;
edged (unedged) boards or strips of plywood along the height of the poured coating;
level, rule;
spatula, bayonet shovel;
container for mixing concrete.

Formwork technology

After you decide on the material for the blind area, calculate its width and the required slope, you can get to work:

First of all, it is necessary to mark the future coverage around the house. To do this, the estimated distance recedes from the walls, pegs are hammered in the corners and a fishing line or cord is pulled.
After that, within the markings along the perimeter of the building, a fertile layer of soil 20 cm thick is removed. The soil at the bottom of the resulting recess is carefully leveled and rammed.
Now proceed to the assembly of the formwork. First, a frame is made from a bar. To do this, at the corners of the recess in the soil, bars are fixed with a height slightly higher than the thickness of the coating being performed. Further along the stretched fishing line, the same bars are installed in increments of 50-100 cm. For greater rigidity, the bars are fastened together with longitudinal bars. Wooden elements are connected with nails or self-tapping screws.
After that, we attach an unedged or edged board to the frame from the timber so that the timber is on the outside of the structure, that is, on the side of the concrete pouring there is a continuous flat surface of the boards. We fasten the boards to the frame with nails.

Attention: so that concrete cannot seep between the boards, the gaps between adjacent elements should not be more than 0.3 cm.

So that after pouring concrete, the formwork structure does not burst and deform, oblique struts are attached to the frame from the outside. The installation step of such spacers is 50 cm. We fasten the spacers to the frame bars using self-tapping screws or nails.
To make it easier to remove the formwork after pouring and hardening of concrete, its inner surface can be covered with a dense plastic film or one layer of roofing material. This material will perform other additional functions:
- will not allow moisture from concrete to be absorbed into the formwork boards, thereby reducing the strength of the concrete coating;
- if there are significant gaps between the formwork boards (especially if unedged boards are used), the coating will prevent concrete from flowing into the gaps.

Along the walls of the house, it is necessary to install an edged board 2 cm thick and slightly higher than the height of the coating in this place. It is not necessary to firmly fix the board, because after the concrete hardens, it will be removed. With the help of this board, we will create the necessary temperature gap between the coating and the walls of the house.

Covering

After the formwork is assembled, you can start making concrete pavement around the house. In this case, the following sequence of actions is followed:

First, a sand cushion 10 cm high is made. The sand layer is leveled, wetted with water and rammed.
After that, a layer of crushed stone 10-15 cm high is made. It is also carefully rammed. At the same time, one should not forget about the necessary slope of the blind area from the walls of the building, therefore, already at the stage of performing the crushed stone cushion, you can take care of creating a slope.
A reinforcing mesh is laid over the rubble.
Now you can start pouring the concrete solution. You can use a factory mix or make your own.

Important: in order for the coating to have a sufficiently high strength and not crack over time, concrete must be poured at a time, without long interruptions in work.

The mortar to be poured must be thick enough so that it can be laid in a thicker layer against the walls of the house, thereby creating the necessary slope. The correctness of the filling is checked using a level. The surface is leveled by the rule.
In the process of hardening in the first days, the concrete surface is wetted with water and covered with a plastic film.
After removing the formwork and removing the board, which is laid along the walls of the house, the formed temperature gap is filled with polyurethane sealant.

How to make formwork around the house with your own hands

How to make formwork around the house. Features and functions of the blind area. Do-it-yourself formwork technology.

The formwork under the strip foundation is subject to increased requirements regarding rigidity and strength. The design should not change in size and shape when pouring concrete. The dynamic load that accompanies the do-it-yourself foundation installation process should not be a test for the formwork.

Basic requirements for formwork

In addition to concrete-fixing properties, the formwork provides optimal temperature and humidity conditions - a necessary condition for the full curing of the mortar. If these conditions are violated, the design strength of the finished support will be seriously reduced.

Important note: a competent formwork device involves the use of materials that are chemically neutral.

Appearance of the structure

Any structure must be made in such a way that it can subsequently be easily disassembled without deformation of the concrete.

Formwork without concrete preparation

If you want to make a formwork for a country house, most often we mean a shallow type of foundation on tapes. Such a base is able to withstand the weight of a small house, and the formwork device does not take much time and effort. All operations can be performed by hand, the formwork in such cases is a small-panel collapsible structure.

In the absence of a concrete screed under the tape base, the formwork is the soil walls of the pit dug under the tapes. A prerequisite can be called from below, the thickness of which should not be less than 20 cm.

Formwork for a strip foundation - the manufacture of a structure from panels that have a dense and durable structure. Boards or sheets of plywood (even used ones) can be used on shields.

Shields are subject to the following requirements:

thickness - from 4 to 5 cm;
humidity - below 21-23%;
width - an average of 15 cm.

The maximum gap between the boards is 2 mm. Formwork panels are mounted on braces supported by stakes driven into the ground. The distance between the braces is determined by the dimensions (height, width and thickness) of the foundation itself.

Important: if the house has standard dimensions, the installation of braces is carried out at a distance of 1 meter from each other.

To fasten the tops of the formwork under the strip foundation, the sections of the shields are fixed with wooden jumpers. This prevents the opening of the structure during the concreting process and the spreading of the mixture. The step for installing fastening bars is from 50 cm to 1 m. To prevent the structure from bending to the sides, the control is carried out by a 2-meter rail.

In order for the formwork under the strip foundation to allow maintaining optimal temperature and humidity parameters of concrete, the structure is lined with a layer of waterproofing from the inside. The waterproofing material is polyethylene film, EDPM-sheet, PVC, etc.

The value of waterproofing is difficult to overestimate: wood is a material with a porous structure. To prevent the absorption of moisture from the concrete solution, insulation is laid. Water from cement milk can seep not only into the walls of the formwork, but also into the ground. Therefore, the do-it-yourself construction device must be done correctly - the installation of the waterproofing layer must provide for a horizontal exit of the concrete mass. The bottom of the trench is covered with several layers of material, which is attached to the walls with a stapler.

Important: when installing the formwork under the strip foundation, its height should exceed the concrete strip by 5-7 cm (video).

Creating a combined formwork

If you want to make a strip base on crumbling soil, you need to make a removable-non-removable type of formwork. Do-it-yourself installation of the structure allows you to save a certain amount of money, but it requires time and effort.

The correct combined formwork includes 2 parts:

internal - fixed, which is made of expanded polystyrene plates (thickness - from 5 to 10 cm);
external - a standard design, which fixes the PPS plates in the desired position with small shields.

The installation of expanded polystyrene is carried out as follows: the material is attached to the ground with ordinary 20-cm nails, and to wood - with removable self-tapping screws. The manufacturer supplies its expanded polystyrene sheets with tongue-and-groove locking mechanisms that prevent the mixture from flowing out and water seeping through.

Important: PPS is much more profitable than wood and does not need additional insulation. Among other things, the installation of light sheets is comfortable and efficient.

To keep the polystyrene foam in a vertical position, do-it-yourself wooden crates are installed. On this topic, you can find a detailed video on the network.

Proper installation of removable and non-removable formwork pursues a number of tasks:

insulation of the foundation above and below the ground;
waterproofing of the tape base;
creation of a removable layer on which the soil load is distributed;
the formation of a smooth surface that can withstand the force of frost heaving.

Nuances of construction

To on a concrete screed, it is necessary to withstand the time interval before it hardens.

When choosing a formwork material, preference is given to moisture-resistant types of plywood - FSF or bakelite boards. Do-it-yourself plywood shields need to be reinforced with wooden bars. Numerous forums and resources on the construction topic contain photo and video reports of a detailed description of the procedure.

To prevent the formwork from deforming the concrete surface during dismantling, the inner surface of the panel structure is lubricated with any of the following compositions:

cement mortar;
hydrophobic mass;
lime milk.

If it is impossible to make formwork with your own hands (no energy, time or for other reasons), the structure can be rented from a specialized company. The cost of renting 1 square meter of imported formwork - starting from 260 rubles. per day of operation. There are several advantages of professional formwork: