How to make formwork for a strip foundation with your own hands

Creating formwork for a strip foundation is an essential step in the process of building a solid foundation, which is vital for any construction project. Formwork acts as a mold, keeping the concrete in place while it hardens to guarantee the strength and form of the foundation. Formwork construction for a strip foundation is a straightforward process that can be completed by any do-it-yourselfer.

The materials must be gathered before formwork for a strip foundation can be created. Generally, you’ll need measuring tape, a hammer or screwdriver, wooden boards or planks, nails or screws, and a saw to cut the wood to size. The size and layout of your foundation will determine the formwork’s dimensions. Make sure the wood can sustain the pressure of the wet concrete.

Next, use stakes and strings to measure and mark the ground where your foundation will be located. This stage aids in visualizing the strip foundation’s precise measurements and location. Making sure that all of the formwork’s markings are precise and have straight lines and angles is crucial.

Cut the wooden boards to the proper lengths for each side of the foundation after the layout has been marked. Boards for the trench’s sides and extra bracing to support the weight of the concrete are usually required. When cutting the boards, don’t forget to take the foundation’s width and depth into consideration.

Form the foundation trench shape out of the cut boards. First, arrange the boards according to the drawn lines, making sure they are firmly in place and, if needed, supported by braces or stakes. Verify the formwork’s straightness and evenness with a level because this will have an immediate impact on the foundation’s alignment and stability.

Add bracing inside the trench to strengthen the structure after the formwork is assembled. Braces aid in preserving the structural integrity of the formwork and stop it from moving when concrete is poured. If the ground is uneven or prone to shifting, use extra stakes or supports on the outside of the formwork to keep it firmly in place.

Lastly, make sure there are no openings or gaps in the formwork that could allow concrete to leak. Use appropriate materials to fill in any gaps, like clay or specialized formwork sealing products. Concrete can be poured into your strip foundation once the formwork is firmly in place and sealed. By taking these precautions, you can be sure that the foundation you lay will be solid and stable enough to support your building project over time.

Materials Needed: Wood planks, nails, hammer, measuring tape, saw
Steps: 1. Measure and mark the layout of the foundation.
2. Cut the planks to the required lengths.
3. Nail the planks together to form the frame.
4. Ensure the formwork is level and securely supported.
5. Check dimensions and alignment before pouring concrete.
6. Remove formwork after concrete has cured.

What is formwork for a strip foundation

Concrete can be poured using formwork. It is a panel structure that resembles a concrete strip and is constructed out of wood, plywood, or polymer materials. According to the measurements given in the project or working drawing, it is constructed right there at the casting site.

The exhibition is typically constructed from edged boards, but there are also more specialized pieces made to be reused. Strength is the primary need for formwork; it must be able to support the loads generated during the pouring and setting of concrete.

Furthermore, the form’s tightness plays a crucial role in stopping concrete leaks and unnecessary material loss.

Of course! Here is a succinct and unambiguous thesis statement for your paper: This guide will walk you through a practical method of building formwork for a strip foundation with readily available materials and simple techniques. Even individuals who are not experienced in construction can create their own formwork with confidence if they follow these detailed instructions. In addition to saving money, this do-it-yourself method gives homeowners and do-it-yourselfers the ability to efficiently ready their property for a solid and long-lasting strip foundation. Gaining proficiency in this fundamental ability will greatly improve your construction projects, regardless of whether you’re creating a brand-new building or remodeling an old one.

Kinds

Formwork comes in various forms.

Their installation and design styles differ:

  • Small and large shield. Most common type.
  • Block. Used for filling wells, columns, etc.P.
  • Volume-adjustable. Used for parallel casting of vertical and horizontal surfaces.
  • sliding. Moves as concrete sets for further pouring.
  • Horizontally movable. A type of sliding formwork for pouring horizontal structures.
  • Lifting and extinguishing. Used for highlight concreting vertical structures.
  • Non -removable. Concrete or polystyrene blocks are used, from which the wall is assembled, and the inner cavity is poured with concrete. The technology is relatively new and has not yet gained widespread.

The majority of these options are shield types because the remaining structures are more for general construction work than they are for the strip foundation.

The degree of heat conservation varies:

  • Insulated.
  • Heating.
  • Special.
  • Unfinished.

During the design phase, the type and material of formwork are selected based on engineering calculations.

Because wooden formwork can be collected in any size, it is the material of choice for most private house projects; however, alternative solutions exist.

What material is used

Several materials can be used to create formwork:

  • Wooden.
  • Plywood.
  • Polystyrene foam.
  • Metal.

There are also alternatives composed of rubber or synthetic textiles. The majority of structures are made of wood because they are affordable, reusable, and available in various sizes.

Because reusable forms are intended to be used in large quantities for castings with identical dimensions and configurations, they are composed of stronger and longer-lasting materials.

Although wooden structures are more affordable and adaptable than prefabricated metal or plywood panels, they require more time to assemble.

How to calculate the quantity?

Using an online calculator is the easiest method of calculation. You input your own data (the height of the tape, the total perimeter multiplied by 2, and the material type) into the corresponding windows.

The quantity of wood in cubic meters is thus determined. This is practical because the typical method involves calculating area and then converting it to cubic meters.

The following calculation method will be helpful for people who don’t trust the online calculator:

  1. The perimeter of the tape is calculated.
  2. Divided by the length of one board, we get the number of shields.
  3. The width of the shield is selected based on the height of the tape (usually a multiple of the width of the boards).
  4. The number of boards in each shield is calculated.
  5. Multiplied by the number of shields.
  6. The result obtained is multiplied by 2.

You must also determine how many strips are required to make stops and crossbars. The number of shields multiplied by the number of slats in a single shield yields the answer.

Since any computation method is very imprecise, it is advised to buy ten to fifteen percent more than what was estimated.

Which board is best to use?

When assembling formwork, the most popular material is typically trimmed pine board. Although planning the boards’ working surface is advised, it isn’t always possible, so unplaned boards are typically used to assemble the boards.

The amount of moisture in the lumber is a significant factor. Using a dry board in this situation is not required, and in some cases, is even undesirable. For a considerable amount of time, the formwork holds a mass of wet concrete that is continuously irrigated with water.

As dry lumber actively absorbs moisture, it swells and gets bigger, which forces individual boards to push out of the plane against the board.

The boards that are used to assemble the panels are between 25 and 40 mm thick. In order for the boards to sustain the loads during pouring and the pressure of liquid concrete on the walls, the tape must be wider and higher.

Installation procedure

There are phases involved in creating formwork:

  1. Vertical cross bars are cut. Their length is 40-50 cm greater than the estimated width of the shields, since they will have to be driven into the ground. To do this, one end is sharpened for better fit.
  2. Preparing the boards. They are cut to length (if necessary) and stored on a flat surface. Optimally – close to the trench, so that you don’t have to carry ready-made shields over long distances.
  3. Lay out the crossbars in increments of 0.8-1.2 m. The top cut is aligned along the line.
  4. Assembling shields. First attach the top board, then attach the rest as tightly as possible. Nails or screws are used.
  5. The shields are lowered into the trench, aligned along their axes and dimensions. The pointed ends of the vertical planks are driven into the ground until the horizontal planks come into contact with the bottom of the trench.
  6. Parallel installed panels connected to each other by crossbars, determining the thickness of the tape. Their role is sometimes played by U-shaped clamps assembled from wooden blocks.
  7. From the outside additional inclined struts are installed, eliminating extrusion of panels when pouring concrete.

To guarantee tightness and stop concrete leaks, plastic film should be applied to the inside surface of the formwork. The loads that are experienced during pouring are very high and arise suddenly, regardless of how carefully and firmly the formwork is assembled. The cracks appear as a result of the shields’ slight divergence. You can avoid wasting material and avoid unnecessary losses by using the film.

Installation of removable plywood formwork

With plywood, you can create sealed panels with a smooth, level surface. You can use the least expensive pine plywood for one-time fills, but for reusable formwork, it is advised to use laminated plywood (the best option) or more durable birch plywood that has been impregnated with drying oil.

The formwork height is used to determine the sheet thickness, which must be at least 10–12 mm. The typical plywood thickness is 14–18 mm.

Order of assembly:

  1. Plywood panels are cut to size.
  2. The frame of the panels is made from wooden blocks (50 by 50 mm). It is a edging located on the outer (non-working) side of the shield. There is no need to connect the planks together, but they are firmly attached to the plywood sheet. For fastening, nails, screws or metal pins are used (for large panels).
  3. Pegs are driven into the trench to support the shields.
  4. The finished shields are placed in the trench and their position is leveled. The distance between parallel panels is fixed with transverse struts, which are subsequently removed before pouring.
  5. Separate panels are connected to each other to obtain continuous formwork walls. The joints are sealed as tightly as possible; if cracks appear, they are sealed immediately.
  6. U-shaped clamps are installed on top of the shields at intervals of about 1 m, holding the shields from being squeezed out during pouring.
  7. It is recommended to cover the inside with polyethylene to seal the formwork and improve the hardening behavior of the concrete. The plywood will remain clean and can be used again or for other purposes.

Once the material has been purchased, you must inspect it and coat the entire surface as well as the ends with drying oil. This will facilitate the formwork’s disassembly and preservation for future use.

How to assemble from polystyrene foam

Since the formwork in this instance serves as both an insulation layer and a mold for casting, it cannot be disassembled. Extruded polystyrene foam blocks that are pre-made and supplementary components such as jumpers and parts for longitudinal connections are utilized.

They are all commercially available and can be ordered in advance in the necessary quantities. This makes assembly much easier and enables you to create an outer cocoon for the concrete strip that is both sturdy and airtight. The technology was developed quite some time ago, but it was never put to use for a variety of reasons; only recently has it started to become more and more well-known.

However, the outcomes enable us to anticipate promising futures for the method.

The formwork is easy to assemble. The blocks are joined together in accordance with the designer’s concept, and jumpers are used to complete the fixing. Apart from generating a pouring mold, the assembly procedure integrates sound and insulation, thereby diminishing the overall labor duration and streamlining the process overall.

The likelihood of mistakes or technological infractions decreases with the number of operations.

The primary drawback of the technique is the elevated expense of polystyrene foam blocks, leading to a rise in construction expenses.

The primary obstacle impeding the proliferation of technology is this.

Installation of removable formwork with insulation

Installing this kind of formwork on your own is done with our proprietary techniques:

  1. The trench has a width equal to the thickness of the tape plus a double layer of insulation. Usually extruded polystyrene foam is used. The insulator sheets are installed vertically on the edge and fastened with nails 20 cm long directly to the walls of the trench.
  2. Before installing the heat insulator, facade dowels are installed on the back side over the entire area. Their ends pass through the material and protrude into the trench to ensure a high-quality connection between concrete and insulation after pouring.
  3. Wooden formwork is installed along the edge of the trench, forming an upward continuation of its walls. The heat insulator is attached to it in the same way as to the ground – with nails, only of shorter length. The technique for creating shields is common, the only difference is that it is installed not inside the trench, but along its edges.
  4. Pouring concrete ensures tight contact of the tape with the insulation, no gaps and tightness of the insulation layer. After the concrete has hardened, the wooden formwork is dismantled, and the heat insulator remains on the surface of the concrete. Taking into account the specifics of the material, it is necessary to install a protective layer of the base sheathing to prevent mechanical impacts on the insulator.

Care must be taken when disassembling wooden panels to avoid damaging the polystyrene foam boards.

Installation of permanent formwork

Concrete is also used to create permanent formwork in addition to polystyrene foam. It is used to make hollow blocks, which are put together like pieces of a construction kit to create a hollow wall the necessary size.

Concrete is then poured inside to fill in the spaces and create a sturdy wall. Although this technology existed before polymer permanent formwork, it was not extensively employed for a variety of reasons.

You can solve a lot of issues with stiffness, density of connection with concrete filling, and finishing work by building such an external frame. It is possible to install insulation and waterproofing without waiting for the concrete to completely harden.

Building materials are saved because traditional formwork is not required.

The formwork assembly method is straightforward and leaves no doubts unanswered. The waterproofing layer is covered with blocks placed in the trench, followed by the installation of the armored belt and the pouring of concrete on the side surfaces.

The process is easy to follow and can greatly accelerate the building of a strong foundation.

How to further strengthen this device?

Because concrete is so heavy, the loads placed on the formwork during pouring can either destroy it or cause cracks that will allow the concrete to escape. In order to reinforce the walls and support the weight of the concrete, other components are employed.

Typically, stakes with inclined stops attached are driven into the ground at a distance of approximately 50 cm from the exterior. Furthermore, horizontal stops are positioned beneath and firmly positioned between the boards’ lower edge and the stakes.

Consequently, several more fasteners are created, enhancing the formwork’s stability and shielding it from damage.

When to remove formwork from a strip foundation?

Traditionally, formwork is taken down ten days following pouring. R Depending on the size and thickness of the tape, various technological options enable earlier or later dismantling within 5–15 days; the larger the tape, the longer the formwork’s curing period.

Extreme caution must be used when disassembling earlier because the tape’s edges and corners are easily knocked off.

Useful video

This video will teach you how to create formwork for a strip foundation correctly:

Building formwork for a strip foundation is an essential first step in creating a solid foundation for any kind of building. In addition to saving money, creating the formwork yourself guarantees that it meets the requirements of your particular project.

First things first, measure the foundation’s dimensions and gather the required supplies. Usually, you’ll need stakes, plywood, wood planks, nails, and screws. Make certain that every material can sustain the weight of the concrete.

Next, draw the foundation’s outline on the ground, making sure it is square and level. This is a crucial step because it will determine how accurate your formwork is and, eventually, the foundation as a whole.

Once the formwork has been marked, start assembling it by cutting the plywood and wood to the appropriate lengths. The vertically arranged timber boards will support the plywood, which will form the formwork’s sides and give it strength and structure.

Using screws or nails, firmly fasten the plywood to the wooden boards, making sure that all of the joints are tight. Stakes must be used to brace the formwork exterior in order to prevent bulging during the pouring of concrete.

Once the formwork has been assembled and braced, inspect it for any openings or crevices where concrete might leak. To create a watertight seal, fill in these spaces with caulking or an appropriate sealant.

Finally, make sure the formwork is aligned, level, and the right size before pouring concrete. Inconsistencies at this point could result in uneven foundations. Once verified, you can proceed with pouring concrete into the formwork by mixing and pouring it according to standard procedures.

Planning ahead, taking exact measurements, and paying close attention to detail are necessary when making your own formwork for a strip foundation. You can guarantee a strong foundation that efficiently supports your building project by adhering to these procedures.

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Fedor Pavlov

Interior designer, author of books on residential design. I will help you make your home not only functional, but also beautiful.

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