Step-by-step instructions on how to make formwork for a strip foundation with your own hands

To install formwork for a strip foundation, you do not need to rent complex special equipment.
If you follow construction standards and follow the sequence of technological processes, then the work can be done on your own and with minimal costs for building materials.

We will tell you in the article how and from what materials to make formwork for a strip foundation with your own hands.

What role does design play?

This is a special structure installed around the perimeter of the trench , which serves as a form for the concrete base and helps to achieve the exact dimensions of the foundation.

When pouring the solution, its walls are subjected to significant loads, so special requirements are placed on their strength. The geometric shape of the formwork must fully correspond to the dimensions of the monolithic base and have precise angles.

It is important for the builder to ensure that there are no cracks or gaps in the walls being erected. Even small holes will expand under intense load and the mixture will begin to flow out. Thus, voids are formed in the foundation mass, which reduce its performance characteristics.

Technologies for strengthening formwork

The procedure for enhancing the characteristics of foundation formwork can be carried out in three ways:

• the use of wooden clamps;
• installation of struts;
• tightening opposite elements with metal pins.

Use of wooden clamps

Wooden clamps are U-shaped structures, the size of the “leg” is half the height of the formwork. The internal length of the clamp crossbar corresponds to the width of the outer part of the formwork structure (distance between the panels + board thickness*2).

To strengthen it, the clamp is installed on the panels, after which it is fixed using self-tapping screws or nails. This allows the formwork structure to reliably maintain the clear geometry of its shape.

Installation of struts

At the points where boards (boards) are connected with transverse bars, the structure can be strengthened using struts. These additional supporting elements allow the structure to keep its shape and not spread to the sides during pouring of concrete mortar.

So, how to properly attach the struts on both sides:

• fastening elements in the upper part of the shield;
• pegs from below, buried at least 15-20 cm into the ground.

It is recommended to install the struts with a small pitch. This will maintain the reliability of the foundation formwork.

Tightening opposite elements with metal pins

The procedure for tightening parts of the formwork that are in the opposite position is carried out as follows:

• a piece of pipe, equal in length to the width of the future monolithic base, is placed between the panels;
• holes are pre-drilled in the docks (boards), through which a metal pin is threaded and the placed pipe is threaded, and securing nuts are screwed onto the threaded ends;
• When the concrete has completely hardened, the studs must be removed and the spacer pipes remaining in the monolith must be filled with cement mortar.

As is clear from the steps of implementing the method, this technology is very simple. However, before properly strengthening the foundation formwork with studs, you need to become familiar with some nuances that cannot be ignored. Otherwise, when pouring, the thread of the stud may be crushed or the fixing nut may “shoot off”. What could cause such an incident?

It’s simple - purchasing fasteners that are of low quality or manufactured in violation of GOST requirements (use of low-quality metal, differences in thread shape, etc.). As a result, such studs cannot withstand a load of more than 1.5 tons.

Accordingly, there is no need to save on fasteners, because standard products with a diameter of 10 mm can withstand up to 6-7 tons of load, which is quite enough to create a high-quality monolithic base.

Kinds

Traditionally, two types of construction are used - non-removable and collapsible .
In the first case, the formwork remains with the foundation after the mortar hardens. Builders save time and labor by eliminating the need for dismantling.

Collapsible formwork is more economical . Its design consists of individual elements that can be reused after the concrete has hardened.

This construction option takes more time and requires special attention from the craftsman to the tightness of the seams. Collapsible devices are convenient when working with complex foundations, as well as when constructing individual elements of structures.

Types and types of strip foundation

Concrete strip foundations are divided into 3 groups by type:

1. Not buried. It is located at ground level on a bed of crushed stone and sand.
2. Shallow. Designed for panel, frame, foam block or wooden houses. Depth of burial – 50-70 cm.
3. Recessed. Used for houses with basements, buildings with heavy weight, and in areas with heaving soil. The laying depth is below 50 cm of the soil freezing level.

The buried option is rarely used - the amount of concrete for the foundation is required very large. In places with cold climates, the laying depth can be more than 2 m.

When deciding which type to choose for construction, pay attention to 4 indicators:

• the load that the base will experience;
• required height of the base;
• ground water level;
• depth of soil freezing.

By type, concrete strip foundations are divided into prefabricated and monolithic. The first consists of individual elements produced in a factory, from which the structure of the desired configuration is assembled. With the same thickness as a monolithic one, it is inferior in strength by almost a third. Among the advantages of this option are the absence of the need to independently calculate the amount of concrete for a strip foundation, ease of assembly and the ability to install blocks at intervals to save money.

Monolithic is made directly at the construction site: cement mortar is mixed and the strip foundation formwork is concreted. The construction of this option is more labor-intensive, but it is stronger than the prefabricated one and is cheaper.

If you have a choice between different types of foundation, you can determine which will be better by comparing the characteristics and features of each

So, when choosing between a strip foundation or a monolithic slab, several parameters are taken into account:

1. Soil type. For weak and non-heaving soils, tape is optimally suited. On heaving areas, it is more advisable to use a stove.
2. Time. Installation of the slab is possible at any time of the year; after installation, construction can continue. It is necessary to pour a strip foundation at above-zero temperatures, after which you need to wait until the concrete gains strength.
3. Life time. The service life of the slab declared by the manufacturers is up to 100 years, but it can be shortened due to high load, unfavorable operating conditions and under the influence of other factors. A prefabricated strip foundation retains its integrity for an average of 50-75 years, a monolithic one - up to 150.
4. Budget. What will cost less – a strip foundation or a monolithic slab? The cost of the tape is several times lower than the slab.

It is impossible to unequivocally answer which is better - a strip foundation or a monolithic slab. To build a house on heaving soils in a short time, the second option would be preferable. On slightly heaving soil, tape is used, which is cheaper and easier, since installation does not require special equipment.

The construction process consists of 5 main stages - preparatory work, installation of formwork, reinforcement and concreting and maintenance of concrete

In order for the resulting structure to have the necessary strength, it is important to know what grade of concrete can be used for a strip foundation, as well as to follow the construction technology

What can it be made from?

It is easier for a builder to use ready-made collapsible formwork, but it is much cheaper to make it yourself from scrap materials. Racks can be made of the following materials:

1. Tree. The most affordable option for self-construction. Wooden panels have such advantages as aesthetics and reliability. They are well processed and fastened using ordinary tools.
2. Metal. Sheets made of carbide metal are characterized by strength, help to achieve an equal concrete surface and further strengthen the foundation.
3. Plastic. Panels made of polypropylene are used as collapsible formwork elements. This material is lightweight and easy to use.
4. Available materials . You can use slate or corrugated sheets that were left over from previous construction projects. But it will be difficult for the worker to achieve accurate geometry and there remains a risk of the solution leaking through the cracks.

For non-removable you can use:

• metal;
• reinforced concrete blocks;
• plywood;
• wood concrete;
• DSP;
• profiled sheet;
• expanded polystyrene;
• glass magnesite.

Which board should I use?

Experts recommend using cheap boards as the main material for formwork for work without the involvement of a construction team. This is an affordable building material that is not difficult to work with without having special equipment at hand.

However, the builder needs to take into account the requirements for wooden panels:

• 
  the type of wood is selected taking into account the humidity, which should be at least 22% (for example, conifers);

• recommended board sizes: width – 15 cm, thickness – from 4 to 5 cm;
• the permissible size of the cracks is up to 2 mm (it is permissible to moisten the boards before pouring to swell and reduce the cracks);
• the wood surface must be free of any defects (knots, breaks);
• At least one side of the board should be smooth and have clean edges.

Compliance of the characteristics of the source material with the given recommendations guarantees that the boards will be able to withstand at least 15 pouring cycles if the technology is followed. Collapsible formwork elements made of chipboard, fiberboard and plywood can be used up to 30 times.

About collapsible formwork

The correct formwork for the foundation has different variations. The following materials are acceptable for construction:

- boards;

— chipboard;

- metal;

- polymer plates.

That is, the formwork for the foundation can consist exclusively of boards. The second option is more practical because plywood is used. Modern construction technologies are increasingly reminiscent of metal. When the formwork is being made, polymer boards also do not lie aside.

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Board construction

While it is not clear how to assemble the formwork, the designs may be different. Experts make full use of pine lumber. When considering opalization, the following parameters matter:

— trench height;

— distance between supports;

— number of shields.

The formwork foundation may include lumber from deciduous trees. The most interesting thing is that the thickness of the board is no more than 4 cm.

Using chipboard on the frame

It becomes clear how to assemble the formwork for the foundation, but chipboard for this is extremely rarely considered. In fact, this is due to low strength characteristics. Builders understand how to make formwork for the foundation, but processing chipboard does not look easy.

In private housing construction, with this option there will definitely be difficulties with moisture resistance.

Work plan:

— marking the work area;

— formation of the frame;

— internal work;

— strengthening the structure;

- checking supports.

At the first stage, the main points are marked. To do this, it is important to place flags on the work area. Experienced experts understand that homemade beacons can be used. First they are installed along the edges. The distance from the edge can be 0.3 meters or more. The main rule is symmetry of the design.

At the second stage, it is recommended to proceed to the formation of the frame. People use solid fiberboard sheets. The beauty is that the panels can be installed one at a time. Builders make sure they are the same size.

Options:

— maximum length up to 2 meters;

— width from 0.2 meters.

It is important to check the chipboard level before starting work. If there is a deviation of more than 10 degrees, it is better to put such workpieces aside.

The chipboard will move even more when poured, so the deviation will be more than 20 degrees, which is critical for the base. Plus, a large amount of material is consumed. If you choose workpieces whose length is less than 2 meters, you can avoid defects. When making shields, it is worth making sure that the marks remain in place.

Connection options:

— staples;

— additional sheets of chipboard.

If you use staples, you can work quickly and without problems. Builders understand that staples are not the most reliable method. The main task is how to make the frame airtight. The following methods are used for this:

- additional sheets;

- film.

If additional sheets are considered, they incur additional costs. Plus, the integrity of the structure is compromised.

When builders choose film, they are guaranteed to get a good result. However, this method is more expensive than the first.

Metal formwork

You need to figure out how to set up a frame for the foundation, and for this you can consider metal structures. They are reliably protected from corrosion before use. Experts know that wooden formwork will not be as strong

To make formwork from sheets of paper, you need to prepare reinforcement in advance for strengthening. The designs are suitable for reusable use. Sheet panels can be folded and moved to another place.

Work plan:

— site marking;

— formation of sheets;

— strengthening shields;

— design verification;

— installation of supports.

When marking the site, you can use any weights. This could be reinforcement or stones. The most important thing is to show the edges of the frame. Metal sheets are installed in pairs. Builders start at the edge and work their way to the middle.

If a large recess is used, there should be no problems with alignment. People also face the problem when the trench is not made level.

In this case, you will have to redo the base, and only then continue work. The most interesting thing is that the sheets can be made immediately with ready-made fasteners:

- screws;

- rivets.

The most common option for shields are screws. Builders use bolts that are screwed into a welded bolt. The process may take a long time. It all depends on the length of the workpieces.

If we consider rivets, they make it possible to quickly complete the job. At the same time, there is a risk of premature opening.

Additional mounting options:

- lock;

- metal valves.

Locks are used on shields that are made of durable metal. Homemade products with a similar option are often found. To weld the lock from the edge, builders make an indent of no more than 4 mm. The most interesting thing is that such structures are considered reusable.

Expert advice:

— reliable fastening of the frame;

— fixation of the upper supports.

If you look at the pouring process, you can see that the main load is on the upper supports. Novice builders try to make the bottom stable, and fix the jumpers on top not rigidly.

Further, when pouring, deformation of the sheets occurs. They remain connected. The most interesting thing is that it is almost impossible to remove the locks after deformation.

When installing top fasteners, it is important to adhere to the following rules:

— width of supports from 0.1 meters;

— mounting angle 90 degrees.

Users select metal sheets with a thickness of 2 mm or more for jumpers. This is quite enough to withstand the load. According to physics, the pressure vector is directed to the side. That is, the support will be stretched to the side.

If you use lintels that are too thick, the builder will simply waste time and resources. The second point concerns the installation angle. Even if a thick workpiece is used, during stretching, it transfers the load to the shields.

When the support is at a slight angle, it begins to unfold when pouring. Eventually it will be right at 90 degrees. The problem is that there is little space in the design for it. As a result, the shields will begin to slowly but surely move apart.

Formwork made of polymer boards

When the conversation turns to how to make formwork correctly, builders talk about the advantages of polymer boards:

- locking connections;

- different types of structures;

— use of profile pipes for rigidity.

Indeed, this is not a bad material for formwork. At the same time, the structure requires timber supports. The assembly of the formwork takes place in several stages, when the required number of polymer slabs is prepared.

The material for the structure can be cut in blocks. Builders prefer to use small elements so that they can be adjusted. Small blocks are easier to handle and level.

Expert advice:

— use of professional tools;

— use of high-quality blocks.

If you handle the blocks manually, there may be chips. Poor quality blocks instantly split.

Advance paynemt

It is not difficult to independently calculate the required number of boards . It is more convenient to have a prepared drawing with exact dimensions. Calculations are carried out for each side of the formwork separately, and then added together.

To calculate the number of units of building material on one side horizontally, you need to divide the length of the tape by the length of the board. To calculate the amount of material in height, you need to divide the depth of the foundation by the width of the board.

At this stage, the builder needs to take into account that the panels should be slightly higher than the depth of the foundation, so the resulting value is rounded up.

The results of the two calculations are multiplied and the answer reflects the required amount of building material on one side of the foundation. Experts recommend having a supply of boards equal to approximately 10% of the calculated data.

To simplify calculations, you can use online calculators at construction services.

Recommendations for design calculations

Beginners absolutely do not understand how to install formwork under the foundation, although experts give recommendations on calculations.

Main stages:

— marking;

- height;

— number of supports;

- width of the ties.

Formwork made from pallets can only hold up after marking. If nothing is known about the height of the trench, supports and ties will not help.

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Auxiliary materials and working tools

To build formwork with your own hands, the builder will need:

• fasteners (nails, screws);
• beams for assembly and selections;
• waterproofing film;
• working tools (level, saw, axe, hammer, chisel and others).

The purchase of auxiliary materials for the builder will cost approximately 40-50% of the cost of the boards.

Tool

You will need regular carpentry tools and some extra ones. Marking tools - marker, water level, building level, plumb line, cord. Hand tools: hammer, hacksaw, carpenter's hatchet, mallet, small sledgehammer, nail puller, crowbar (used for removing formwork), wide “priming” brush (for coating with a water-repellent composition). A small sapper blade will come in handy, but you can also use a regular bayonet blade. If you use self-tapping screws, you definitely need a good screwdriver. Having a chainsaw, electric saw, circular saw or even a jigsaw will greatly facilitate the work.

Manufacturing and installation

The whole process can be divided into several key stages:

1. Preparatory – calculations and purchase of building materials.
2. Transition to field work - marking the site and digging a trench according to the specified parameters.
3. Production of blanks for panels (if it is not stamped material for formwork).
4. Driving support beams into the ground.
5. Installation of dampers.
6. Strengthening.

Shield assembly

The size of the dampers is chosen taking into account the geometric shape of the base so that their height is greater than the depth of the concrete pad. The length of the elements is chosen arbitrarily, but the optimal value is considered to be no more than 3 m. The total length of the dampers must correspond to the length of the tape.

Shields can be a prefabricated structure made of boards. Fixing bars are attached across the boards in increments of 50-80 cm. The central and outer bars can be longer than the height of the formwork and have pointed ends that will go into the ground.

Installation Features

The finished dampers are installed according to the markings strictly in a vertical plane.
For convenience, you can drive in vertical beams along the perimeter of the base in advance and align the walls of the formwork closely to them. The worker must ensure that the elements fit tightly so that concrete does not flow out through the cracks . Armed with a level and a hammer, he needs to align all the shields exactly in the same plane and at the same height.

If the shields do not have long bars that could go into the ground and hold the structure, then vertical bars are first placed along the perimeter of the trench. These elements will serve as support for the shields, which must be tightly attached to them using spacers and slopes.

Strengthening

The walls of the formwork are subjected to heavy loads during concrete pouring and may fall apart. To prevent this from happening, additional elements are installed to strengthen the structure.

From the outside, the walls are supported by braces and supports . They are placed in increments of no less than 1 m. Particular attention is paid to the corners of the formwork, where support is needed on both sides at once. If the height of the shields is more than 2 m, then the supports are placed around the perimeter in two rows: upper and lower.

Basic information about strip foundations

Strip foundations can be used in the construction of houses with or without basements. Either way, you get significant savings when choosing this type of foundation.

When constructing a basement, it is advisable to build a foundation in a ready-made pit using double-sided formwork; in this case, the foundation will play the role of basement walls.

A simpler method is to pour the structure into specially prepared trenches. In this case, you can save on the cost of formwork, because it is enough to install only its outer part, which, when using modern materials (formwork using extruded foam), will also become a reliable element of insulation and waterproofing.

The calculation of foundation parameters must be carried out by a civil engineer who will be able to calculate all design parameters depending on the condition of the soil, the presence of groundwater and other factors.

The entire technology of pouring a strip foundation can be divided into several stages:

• Preparatory and excavation work
• Preparing the base, installing formwork
• Manufacturing of reinforcing frame
• Pouring concrete mixture

Let's look at all these stages in more detail.

Preparatory and excavation work

The main issue of preparation is the calculation and purchase of necessary materials. If you decide to prepare the concrete mixture yourself, which will help somewhat reduce the cost of pouring a strip foundation, but will significantly increase the time of its construction, you need to bring the required amount of crushed stone, sand, and cement to the construction site.

In addition, before starting work, it is necessary to purchase formwork material and reinforcement; all this can be imported during the excavation process. In addition, to prepare concrete, you need to make sure you have a concrete mixer, which, in extreme cases, can be rented. But we would still recommend using ready-made concrete mixtures, which will greatly simplify the work.

Construction of a clay castle

As already mentioned, concrete can be laid either in trenches or in a foundation pit. In addition to the fact that constructing a pit will simplify the work on arranging the basement, in this case it is possible to arrange additional waterproofing of the building by installing a clay castle over the entire area, which will significantly reduce the access of groundwater to the building.

When performing excavation work, it is necessary to constantly monitor elevations; this will be the basis for the stability of the entire building.

In addition, trenches must be monitored along the axes of the building. To do this, they resort to the so-called cast-off, it is performed as follows. 2 m are retreated from the lines of the future walls, supports are mounted to which the boards are attached. Thus, we obtain a structure that follows the entire contour of the building, which facilitates excavation work.

Foundation stripping

How to assemble and install dampers from various materials?

Previously, the general algorithm for installing formwork was considered. The use of different materials for shields requires its own installation features. It is easier for a builder who does not have special equipment to build a structure from boards, plywood or polystyrene foam.

Installation of boards from boards

This option is considered one of the easiest to install and the cheapest in terms of cost . When working with boards, a craftsman can make do with ordinary woodworking tools.

When there are cracks on the surface of the source material, leakage of the solution can be prevented using a plastic film that is attached inside the system.

Ordinary boards are a popular building material for formwork and even a beginner can cope with their installation. The only drawback is the need to strengthen the structure with additional elements (ties, supports, metal pins).

Made from polystyrene foam

Expanded polystyrene is a practical and high-quality material . Ready stamped blocks serve as shields. They quickly assemble into a single structure. The elements fit into grooves and are secured with threaded ties.

Difficulties may arise at the stage of selecting sheets of expanded polystyrene, when arranging the necessary corners and curves. Before pouring the concrete mixture, a reinforced frame can be placed in the formwork. A significant drawback is the high cost of polystyrene foam.

How to install plywood correctly?

Sheets of plywood will serve as reliable walls for the formwork . The assembly of elements is not much different from the standard scheme. The master’s task is to assemble a structure that accurately replicates the geometry of the base.

To maintain the accuracy of the width of the tape along the entire perimeter, identical bars are attached between the sheets of plywood. When working with a massive foundation, experts recommend strengthening the walls with screeds.

Requirements for formwork

Since this entire system is created in order to give shape to concrete and reinforced concrete products, it must be strong and elastic enough to withstand the pressure of the mass of liquid concrete. Therefore, quite serious demands are placed on formwork materials in terms of strength. In addition, the assembled panels must have a smooth and even inner surface: it forms the foundation walls, and then hydro- and/or heat-insulating materials are fixed to them. It is easier to attach them to flat (at least relatively) surfaces.

Materials for removable structure

Construction organizations have metal structures assembled with studs and bolts. In private construction, formwork panels are made from boards, moisture-resistant plywood and OSB. Wooden blocks are used as stops and spacers. No one bothers to make a structure from metal, but it is very expensive and unprofitable for one-time use.

When building a cottage or country house, boards made of boards are most often used. You can use any species, both coniferous and deciduous. It is better to take an edged one: the solution should not ooze through the formwork, but this is impossible to achieve with an unedged board.

What does the formwork for a strip foundation look like in section?

With a foundation height of up to 1.5 meters, the formwork board must have a thickness of at least 40 mm. The panels are fastened using bars with a section of 60*40 mm or 80*40 mm. If the height of the foundation is large - it is deep - such bars will not be enough to hold the mass of concrete. If the height is more than a meter, you need to use a block of 50*100 mm or more. For assembly use nails or screws. Their length is 3/4 of the total thickness of the board and bar (for the above sizes 60-70 mm).

Formwork is also made from plywood. There is even a special formwork, laminated with paper with synthetic impregnations. The coating has increased resistance to aggressive environments, which is liquid concrete. This material is labeled FSF (using formaldehyde glue).

The thickness of plywood for formwork is 18-21 mm. The panels are assembled on a metal or wooden frame. The wooden frame is made from a 40*40 mm block; you need to use shorter fasteners - 50-55 mm. When using plywood, it will be easier to work with self-tapping screws: nails are difficult to hammer in.

Construction of formwork panels made of plywood and OSB

OSB is not often used for this purpose, but this option also exists. The thickness is about the same: 18-21 mm. Structurally, it is no different from plywood panels.

Select the dimensions of the sheets of these sheet materials based on the dimensions of the required formwork panels - so that there is as little waste as possible. No special surface quality is required, so you can use low-grade materials, which are usually called “construction materials”.

Decide for yourself what to make the formwork for the foundation from: it depends on the prices for these materials in your region. The usual approach is economic: whatever is cheaper is used.

How to save money?

Laying the foundation with your own hands, in most cases, is explained by the desire of the master to save money on hiring a construction team. Therefore, it is advisable to consider additional ways to save.

Filling in layers

The use of removable formwork allows builders to reduce the cost of purchasing materials. The method involves the gradual pouring of concrete mixture .

After the solution hardens, the structure is dismantled and reassembled on another section of the tape. During the warm season, approximately 3-4 days pass between filling cycles.

Vertical division

The concreting process can be divided into stages both according to the length of the foundation and its height . When the bottom layer of the mortar has completely hardened, the cement laitance must be removed from its surface and you can begin the next cycle of formwork construction.

To make the building material last longer, the surface of the dampers can be covered with plastic film or treated with an aqueous solution of slaked lime.

The procedure for reinforcing a strip foundation

The existing scheme for reinforcing a strip foundation for building a house requires following several mandatory rules:

1. Application when carrying out reinforcement of rods of class A400
2. Minimizing the use of welding when connecting rods, as this technology helps to weaken the sections
3. At the corners, the frame can only be tied; the use of welding at the corners is not recommended
4. The protective layer of concrete used in a particular situation must be at least 4 centimeters to protect metal elements from the negative effects of the environment and corrosion
5. The use of smooth reinforcement is not recommended
6. During laying, concrete must not be able to get stuck between the rods, which will eliminate control over failure due to too frequent placement of metal rods

Detailed step-by-step instructions with photos and videos provided for clarity will help you create a reinforcement frame. A significant advantage of reinforced strip foundations is the combination of high reliability and affordable cost. Steel and concrete are high-strength materials.

This is important for creating a foundation for construction on any soil, except for naturally stable and reliable rocks. In other situations, reinforcement of any foundation will eliminate damage caused by stress

How is it formed

When carrying out work such as reinforcing a strip foundation, the drawings include three groups of rods:

• Working rods used for laying along the belt
• Horizontal elements arranged transversely
• Vertical options, transverse

The task of transverse reinforcement is to connect all working elements into a single unit of reliable, innovative working rods that is stable in use. They are often called clamps.

An important feature of the work is the use of SNP and other regulatory specialized documents for activities such as reinforcement of strip foundations. When calculating, SNiP 52-01-2203 is used

In this regulatory document it is easy to find all the necessary calculations for creating reinforcement for the strip foundation of a small country house.

What requirements for concrete are determined by regulatory documents?

If you follow the order of creating reinforcement, it is important to comply with the mandatory requirements for the concrete used in a particular work. When creating a strip foundation with your own hands at the site of future construction, it is worth considering that the main characteristics of the strength of concrete structures include resistance to axial compression, readiness to withstand tension and not respond to transverse fracture

Reliability correction factors can vary from 1 to 1.5

When creating a strip foundation with your own hands at the site of future construction, it is worth considering that the main characteristics of the strength of concrete structures include resistance to axial compression, readiness to withstand tension and not respond to transverse fracture. Reliability correction factors can vary from 1 to 1.5.

Turnkey price

To evaluate the benefits of self-construction, the master should have an idea of ​​the average market cost of the service in Russia:

Basic rules for installing formwork

Prefabricated formwork for creating monolithic reinforced concrete structures consists of panels or blocks connected by fasteners and reinforced with supports. The nuances of assembly depend on the type of formwork and the material of its manufacture.

But there are also general installation rules. Therefore, it is worth getting acquainted with the peculiarities of the work. When performing installation work, the following rules must be observed:

Advice! Particular attention must be paid to checking the tightness of formwork forms assembled from boards. In this case, not only the joints, but also the shields themselves may become leaky. Large cracks are filled using slats, and small cracks are filled with tow.

How to further strengthen it?

When it is necessary to pour a large amount of concrete mixture, the system is reinforced with metal pins.
Sometimes the walls of the formwork can split apart under the weight of the solution. In this case, it is advisable to install screeds along the top of the structure .

To fix the shields, the walls are supported with beams in one or two rows, depending on the depth of the concrete base. The foundation will be stronger if wooden pegs or reinforcing rods are driven into the ground around the entire perimeter at intervals of at least 0.4 m.

Removable and non-removable

According to the principle of use, formwork can be removable (collapsible) or permanent. As the name implies, the removable one is disassembled after the concrete gains strength above critical (about 50%). Therefore it can be used several times. Depending on the material, the same set can withstand from 3 to 8 pours; industrial options can be used several dozen, and some hundreds of times.

Removable formwork is dismantled after the concrete has gained 50% strength

Permanent formwork becomes an inseparable part of the foundation. Such systems began to be used relatively recently. They are made mainly from extruded polystyrene foam. Blocks of different configurations are produced, which are connected to each other using locks and metal pins. From the blocks, like from a construction set, the required shape is assembled.

Fixed formwork becomes part of the foundation - it also doubles as a heat insulator

Fixed polystyrene foam formwork not only gives shape, but also acts as thermal and hydro insulation and also has sound insulating properties. It costs a lot, but it immediately solves many problems, and the time spent on building the foundation is significantly reduced.

There is another type of permanent formwork - hollow concrete blocks. They also come in different configurations - wall, corner, radius, etc. They consist of two or three walls and several jumpers that hold the walls in a certain position. They are connected to each other using locks and reinforced with rods.

When to shoot, after how many days?

Dismantling of the structure is possible only after the solution has completely turned into a solid mass . The duration of the process is determined by the massiveness of the foundation, its depth, the grade of concrete, and the ambient temperature.

Under suitable weather conditions, foundations for heavy structures require up to 4 weeks to fully cure. For private housing construction, demoulding can be done after 20 days.

After dismantling, gaps may remain on the surface of the base. These defects are filled with soil or filled with cement mortar.

Tips and tricks

The process of strengthening (strengthening) the foundation formwork should be approached carefully and carefully. When performing, you need to take into account:

1. Construction type. The removable one is reinforced without taking into account the aesthetics of the structure. The non-removable one should be approached carefully, using inconspicuous or completely invisible fasteners, because it will become an integral element of the future structure, often carrying a decorative load.
2. Material of formwork equipment. To fix boards and boards, you can use both wooden and metal elements.

Concrete slabs must be joined by welding existing structural embedded parts. Expanded polystyrene panels are assembled using a tongue-and-groove method and reinforced with threaded ties.

1. Concrete pressure This is a value that depends on the dimensions of the foundation being built (width, depth), as well as the composition of the working mixture and the height of the pour.

These factors are only part of the nuances that require consideration during the installation and strengthening of formwork for foundation structures for private housing construction, outbuildings, industrial or other purposes.

Therefore, if non-specialists are unsure of their strengths and skills, it is better not to engage in amateur activities and turn to builders with experience to create a high-quality foundation for a future structure.

Do-it-yourself foundation formwork from scrap materials

Not only specialized materials are used to assemble formwork. For example, a small form for the foundation can be made from available materials. These could be old doors, pieces of furniture, boards, slate, etc. The main advantage of this method is its low cost.

It is worth noting that it is quite difficult to design such a form, since it is quite difficult to select the necessary parts. It is very difficult to achieve the tightness of formwork made from improvised materials. That is why this method is not popular. It can be used in the construction of a concrete fence. A form for a fence made using this technology requires taking into account possible problems that sometimes arise during work.

Studs for screeding formwork panels

When using any materials, it is recommended to use special formwork pins. They are necessary to tighten the walls of the structure. The rigidity of freeform formwork is much lower than that of forms assembled from specialized parts. When organizing this option, the risk of solution leakage increases.

It is recommended to take into account that in this case you cannot do without additional fasteners. To ensure good rigidity and stability of the structure, it is necessary to install special wedges and supports. It should be remembered that this method absolutely cannot be used when organizing the foundation for residential buildings.

How to make formwork for a foundation with your own hands (removable): preparatory stage

Before starting the assembly of a removable forming structure, it is necessary to purchase the appropriate tools and materials, and it is also worth preparing the area that has been designated for installation of the foundation. The most common is the strip base. To make removable formwork you will need the following materials:

The calculation of materials for organizing the formwork of a strip foundation is carried out based on the dimensions of the future foundation. It is necessary to take into account several requirements to correctly implement the forming design. The height of the formwork assembled from plywood must exceed the level of the base by 50 mm. The spacers are installed at a strictly defined distance from each other (700-1000 mm).

It is important to remember that there should be as many stakes as there are side supports. The shields in the corners are fixed together. For this purpose, side jumpers are used. When organizing formwork, a dense film made of polyethylene material is used. It should cover the entire inside of the fence. Before you begin, it is recommended to watch training videos on how to properly make a foundation.

Preparing the place where the base will be cast includes several types of work. First of all, you need to dig a ditch in the ground. The trench must correspond to the designed depth. In this case, it is required that the width of the ditch have a margin of 10 cm greater than that of the future strip base.

Next, you need to level and compact the soil at the bottom of the trench. Then the walls are leveled. One of the most important conditions when pouring a foundation is the organization of a special cushion of gravel and sand at the bottom of the ditch. The standard width of this layer is 10-15 cm.

In soil that has a high density coefficient, a trench is made corresponding to the width of the concrete strip. Moreover, the formwork in this case should be located above the soil level.

Formwork for board foundations

Construction of wooden panels and their connection

It is convenient to assemble structures for strip foundations from panels prepared in advance. The panels are knocked together from edged boards and perpendicular bars using nails or connected with self-tapping screws. When assembling the boards into a single system, at the joint, an overlapped piece of ribbing is installed, which is attached with self-tapping screws to both boards. This fastening allows you to block concrete leakage at the junction and give the structure additional rigidity. Spacers are placed between the shields, which are made from wooden blocks.

The height of the shield for a strip foundation may be slightly higher than the planned height of concrete pouring. In this case, immediately before pouring, mark the level to which it is necessary to fill the formwork in order to obtain the desired height of concrete. The second option is that the height of the shield is equal to the planned height of the foundation. In such a situation, the upper edge of the shields should be level.

When pouring monolithic walls, the height of the boards does not matter, since it is carried out in stages, and the boards are gradually rearranged. The length of the panels that are installed from the outside of the foundation is not important. It is important that the length of the internal formwork is equal to the length of the planned foundation from the inside. Otherwise, the shields will not be able to be installed, or they will flood into the foundation in the corners, which will make it impossible to dismantle them without damaging and destroying the base in the corners.

Laminated plywood for formwork: material features

Laminated plywood is a traditional material used in the assembly of forming structures. This is due to the fact that it has the most suitable technical and physical characteristics. The laminating layer is located on the surface. Its function is to protect wood from moisture.

The surface texture of laminated sheets may vary. There are smooth and grained plywood. When choosing laminated sheets, first of all you need to pay attention to their thickness, which can vary from 3 to 40 mm. The price for a sheet of laminated plywood for formwork ranges from 1.5 to 4 thousand rubles. The cost depends on the type of wood from which the product is made, its thickness and dimensions.

Laminated plywood is a convenient material for formwork

How to choose formwork for the foundation? The best option is considered to be sheets with a thickness of 18 to 21 mm. They are most often used in the construction of formwork for foundations and other building elements. Such products are distinguished by their ability to withstand high loads. Moreover, their weight allows for simple transportation and installation. The dimensions of standard sheets are 1250x2500 mm.

Choosing lumber for formwork

It is quite difficult to find and “rent” ready-made panels and formwork fasteners for reusable use during the construction season. It's easier and faster to assemble it yourself.

In fact, for a relatively small foundation it is a fence for concreting its above-ground part. The entire structure is temporary and it is advisable to plan ahead for the reuse of materials. To make shields, most often an edged board is used.

Although at first glance, it is more logical to use panel materials: plywood or OSB. However, it is not advisable to expose them to prolonged exposure to moisture. At the same time, installation for its intended purpose usually occurs later than the use of edged boards.

What boards are needed for foundation formwork

Any - the length is arbitrary, if possible it is preserved. Thickness: from 25 to 50 mm (that is, with a high probability, anything will do: inch, thirty, forty and fifty).

By and large, everything is decided by further needs. Afterwards, scaffolding is assembled from this board. Next, it goes to the rafters, sheathing, subfloors - there will be no release anyway.

This means that the thickness of the board for the formwork is selected in advance based on its further intended use, and a reasonable approach: low narrow formworks, such as for a small bathhouse, or auxiliary outbuildings, can be assembled even from “inches”.

The most budget option - we use a slab for formwork of the foundation

Situations are different, let's consider preparing the foundation for concreting with minimal investment. In this case, which board is used for formwork - the answer depends entirely on the desire to save money.

Let’s say right away that it is very advisable to take a “business” croaker, that is, as convenient as possible for use. The positive aspect of such an acquisition is the relatively low cost of the material.

A significant drawback is that it will require effort and a lot of time for processing and assembly, because most likely the croaker will have to:

• Edge - determine the possible width of the board and file away any excess irregularities, since when assembling the gaps between the boards need to be minimized.
• Sand it - in austerity mode, there is a high probability of its further use.
• Mark and file the seats for the crossbars in advance - for assembling the slab into the formwork panels.

For strong, high-quality shields, it is precisely the seats for their crossbars that are needed. In principle, it is easy to cut them with a circular saw or chain saw, using a simple jig to ensure the same thickness.

It is advisable to file thin sections of the slab. Spacers for them should be used minimally and carefully - due to the semicircular back side of the boards, it will be difficult to maintain an even front plane of the boards.

Limitations on the use of boards after formwork

The possibility of reusing the board after dismantling the formwork can be complicated if it is insufficiently protected from water, dirt, and cement. It is better not to plan the board for making decorative surfaces. Since even independent planing or grinding can be complicated by contamination from concrete.

And this is not counting missing, unremoved nails, screws, staples from a stapler. The knives of power tools suffer from them, and the abrasive belts of sanding machines break. In addition, carpentry shops do not process second-hand lumber - to save equipment, they prefer to work only with fresh wood.

How to treat wooden formwork to minimize the negative consequences of concreting? In industrial buildings, formwork panels for repeated use are treated with a release agent.

But for a private owner, this is acceptable only with further treatment of the board with waterproofing materials and use in places of high humidity. More often than not, they try to keep the board as clean as possible. To do this, it is simply reliably covered - the finished formwork panels are wrapped in polyethylene.