Any building needs a solid foundation. In individual construction, pile-tape and tape structures are most common. The only way to create a form for the foundation of a building is quite often the construction of formwork. In the process, plank shields are used.
The biggest disadvantage of the design is the deformation of the boards under the pressure of the mortar. However, today there are new materials on the market that allow you to replace the boards and solve this problem. As such, sheet plywood is used. It costs more than planks, but has many advantages.
Why choose plywood
Plywood formwork has many advantages, among them should be highlighted:
- evenness and smoothness of the material;
- moisture resistance;
- easy installation;
- less likely to warp;
- reducing labor costs.
During the casting process, plywood is able to retain itsproperties due to moisture resistance. You can install it yourself. Elements will not deform when filled. If we compare plywood with wooden boards, then the first one is installed with less time.
Choosing plywood
If you need to build plywood formwork, then first you need to choose the material. If its reuse is not planned, then it is better to purchase laminated sheets. The cost of one will range from 560 to 1200 rubles. Such differences are related to manufacturers and characteristics.
High-quality laminated plywood is a multi-layer board that is covered with a polymer film on both sides. It is resistant to moisture and mechanical stress. This building material is the most durable among other types of plywood, such as FK and FSF.
You can purchase new or used material. In the first case, we are talking about laminated plywood 18 mm, which can be used up to 100 times. If the canvases are operated in harsh conditions, then their turnover is reduced up to 70 times. By purchasing used material, you get the opportunity to use it up to 55 times. The resource is checked by tests and affects the final cost. Each of the mentioned resources will be enough to lay the tape base.
Before you build plywood formwork, you can consider alternative solutions. For example, a variety of fabrics marked FK are sheets that are made withusing urea glue. It contains a lot of formaldehyde resins. Therefore, this plywood is not suitable for fixed structures.
These boards are moisture resistant, and their resistance to moisture is lower than that of laminated plywood. However, with careful use, the turnover of FC reaches 25 times. This material costs up to 1950 rubles. per sheet.
For the manufacture of FSF plywood, formaldehyde adhesive is used. It gives the sheets strength and resistance to moisture. This film faced plywood 18 mm has improved wear resistance qualities. The turnover reaches 43 times. It is based on an adhesive composition, which, under the influence of moisture and temperature, begins to release phenol. You can use this type of sheet only for outdoor work. For 1 sheet of FSF you will have to pay 2800 rubles.
Plywood formwork may consist of FBK. In this case, we are talking about plates, the layers of which are interconnected by a lacquered bakelite composition, resistant to moisture and not afraid of temperature changes. Cloths are steady against climatic and atmospheric loadings. This plywood is moisture resistant, and its price reaches 3500 rubles. per sheet. It can be used in any operating conditions.
An analogue in terms of wear resistance and mechanical strength is Finnish plywood with FB marking, which is used in conditions with high humidity. The most common solution is FBS sheets. They are based on veneer, which is processed with alcohol-based bakelite glue. As a result, it is possible to obtain microorganism-resistant webs that are capable ofwithstand horizontal and vertical loads.
8mm plywood is the thinnest material. On sale you can find 15 mm sheets. The final value will depend on the characteristics of the foundation. There is glue in the layers, which gives the plywood the property of flexibility. The building material has high bending strength. The price per sheet reaches 3800 rubles.
Build instructions
Before installing the formwork of 8 mm plywood, it is necessary to prepare a trench, deepening to the calculated value. If it is planned to erect a pile-tape base, then it will be necessary to drill wells along the bottom of the trench. The latter are re-cleaned, and then a layer of sand is poured onto the bottom, which must be compacted. The surface is checked with a level.
Installation of plywood
Moisture-resistant formwork plywood should be placed on both sides of the trench. Cloths should be located around the perimeter and under the bearing walls. In order to exclude displacement, fastening is carried out with spacers, braces and jumpers. The sheets are connected to each other with steel pins. 10 mm holes are drilled in plywood for this. The walls of the holes are covered with drying oil to prevent moisture penetration.
A corrugated plastic tube is placed between the sheets along the width of the trench. To match the distance between the sheets, wooden bars are installed. When disassembling the structures, the studs are removed from the tube. The pin is inserted into the hole and fixednuts. The side walls are reinforced with rails installed in three rows. A 10mm hole is drilled into each rail.
How to ensure smoothness
If the foundation is planned to be high, then another rail should be located in the center. Staples are fixed on the side corners with self-tapping screws. Fasteners must be located on the outside. This will ensure the smoothness of the internal surfaces. Nails are hammered from the inside and bent. All cracks are sealed to prevent concrete leaks. To protect the plywood from pressure, clamps are put on it. From the outside of the formwork, stakes are driven into the soil, which are pulled together with wire from above.
Use racks
Stands for formwork are used in the construction of ceilings using monolithic technology. At the same time, it is possible to perform work at a height of up to 5.5 m. When constructing ceilings at an impressive height, telescopic structures are used. If the loads are more impressive, you should use a system on volumetric racks for formwork.
In closing
When installing the form for the foundation, it will be necessary to cut the sheets. For this, laser cutting technology is used. This allows you to ensure the speed of work and helps to achieve aesthetics. Do-it-yourself plywood cutting using this technique is characterized by low cost and high accuracy. The cutting width is minimal, while the equipment is multifunctional.
