Any building needs a solid foundation. In individual construction, the most common pile-tape and tape structures. As the only way to create a form for the base of the building, construction of the formwork quite often appears. In the process, plank shields are used.
The biggest drawback of the design is the deformation of the boards under the pressure of the solution. However, today there are new materials on sale that allow you to replace the boards and solve this problem. As such, sheet plywood is used. It is more expensive than boards, but has many advantages.
Why choose plywood?
Plywood formwork has many advantages, among them it should be highlighted:
- evenness and smoothness of the material;
- moisture resistance;
- easy installation;
- less chance of deformation;
- reduction of costs for work.
In the process of pouring, plywood is able to maintain its properties due to moisture resistance. You can install it yourself. Elements will not deform when filled. If we compare plywood with wood shields, the first is installed with less time.
Plywood selection
If you need to build a formwork from plywood, then first you need to choose the material. If its reuse is not planned, 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 specifications.
High-quality laminated plywood is a multilayer plate, which is coated with a polymer film on both sides. It is resistant to moisture and mechanical stress. This building material is the most durable among other varieties of plywood, such as FC 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 blades will be operated in harsh conditions, then their turnover is reduced 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. To bookmark the tape base of each of the mentioned resources will be enough.
Before you build a formwork from plywood, you can consider alternative solutions. For example, a variety of cloths with the FC marking are sheets that are made using carbamide glue. It contains a lot of formaldehyde resins. Therefore, such 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 the FC reaches 25 times. This material costs up to 1950 rubles. per sheet.
In the manufacture of FSF plywood, formaldehyde adhesive is used. It gives the sheets strength and resistance to moisture. This 18 mm laminated plywood has improved durability. Turnover reaches 43 times. The basis is the adhesive composition, which, under the influence of moisture and temperature, begins to release phenol. Use this kind of sheets is possible only for outdoor work. For 1 sheet of the FSF 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 bonded to each other with a varnish bakelite composition, resistant to moisture and not afraid of temperature changes. Cloths are resistant to climatic and atmospheric loads. This plywood is moisture resistant, and its price reaches 3500 rubles. per sheet. It can be used in any operating conditions.
An analogue in matters of wear resistance and mechanical strength is Finnish plywood with the 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 bakelite glue. As a result, it is possible to obtain webs resistant to microorganisms, which are able to withstand horizontal and vertical loads.
8 mm plywood is the smallest material. On sale you can find 15 mm sheets. The final value will depend on the characteristics of the foundation. Glue is present in the layers, which gives the plywood a flexibility property. The building material has high bending strength. The price per sheet reaches 3800 rubles.
Construction Instruction
Before installing formwork of 8 mm plywood, it is necessary to prepare a trench, having gone deeper by the calculated value. If it is planned to build a pile-tape foundation, 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.
Plywood installation
Moisture-resistant formwork plywood must be placed on both sides of the trench. Cloths should be located around the perimeter and under load-bearing walls. In order to exclude displacement, fastening is carried out with struts, braces and jumpers. Sheets are interconnected by steel studs. 10 mm holes are drilled for this in plywood. The walls of the holes are covered with drying oil to prevent moisture penetration.
A corrugated plastic tube is exposed between the sheets along the width of the trench. To match the distance between the sheets, wooden blocks are installed. When disassembling structures, the studs are removed from the tube. The hairpin is inserted into the hole and secured with nuts. The side walls are reinforced with rails installed in three rows. A 10 mm hole is drilled in each rail.
How to ensure smoothness
If the foundation is planned to be made high, then another rail should be located in the center. Staples are fixed on the side corners using self-tapping screws. Mounts should be on the outside. This will ensure the smoothness of the internal surfaces. The nails are driven inside and bent. All cracks are closed to prevent leakage of concrete. To protect the plywood from pressure, clamps are put on it. On the outside of the formwork, stakes are clogged into the soil, which are pulled together by wire.
Using racks
Formwork stands are used in the construction of floors using monolithic technology. At the same time, it is possible to perform work at a height of up to 5.5 m. When constructing floors at an impressive height, telescopic structures are used. If the loads are more impressive, you should use the system on volumetric racks for formwork.
Finally
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 precision. The cutting width is minimal, while the equipment is multifunctional.