So, what is wall formwork? It is called a simple structure consisting of a number of stacked panel blocks. These components are simply attached in the required position at a specific height and are needed to hold the concrete mixture until it is completely dry.
In recent years, the volume of monolithic construction has increased, because of this, wall formwork has become the most necessary and sought-after auxiliary material. Monolithic buildings gained popularity due to the speed of construction, excellent strength, and the ability to save on materials. In most cases, the high reliability of the completed building is determined by the formwork.
Any form consists of the following elements:
- supporting frame;
- fasteners;
- panel;
- stiffening rib.
What materials can removable formwork be made from?
- Steel. It is characterized by high mechanical strength and the ability to cope with the most severe loads. Steel formwork has become widespread in large-scale construction and can withstand over 200 work cycles. The only drawback is the significant mass of structural elements, which requires the use of a crane during assembly and disassembly.
Removable formwork - steel wall formwork
- Aluminum. It is used in the process of pouring small structures. This is due to the weak resistance of aluminum to deformation under high loads. The low weight of aluminum formwork allows it to be installed manually without any problems.
Removable formwork - aluminum wall formwork
- Wooden. The most popular type of formwork in private construction. Wooden formwork has a very low cost and can easily be made independently. The main materials used for its assembly are ordinary boards and plywood. It is worth noting that when assembling panels using plywood, special attention should be paid to the dimensions of the structure being poured. With a large volume of concrete, plywood may not withstand the pressure and collapse.
Removable wooden formwork
— Composite. Due to its high cost, it is justified only for repeated use. It is distinguished by reliability, durability, modest weight and ease of installation. Plastic structural elements can be easily and quickly cleaned of concrete residues. This reduces the time and complexity of preparatory work before the next pour.
Removable plastic formwork
Manufacturing of composite boards
A slab made of steel concrete, the load-bearing element of which is corrugated sheeting, is called composite. Corrugated sheeting of increased rigidity carries the functional load of additional reinforcement, withstanding the pressure of the reinforced concrete mixture on the surface of the floor. In this case, it is permissible to reduce the cross-section of the frame reinforcement rod, reducing the cost of manufacturing the slab.
Construction of a composite reinforced concrete slab with permanent formwork made of corrugated sheets
The main indicator of using a grade of corrugated board for composite slabs is the height of the corrugation . This parameter allows you to use a smaller number of load-bearing beams and install them at a greater distance from each other. The short span allows the use of profiled steel of lower wave height to create composite floor slabs at a cost lower than super load-bearing. The maximum length of profiled steel sheet is twelve meters.
The fastening of corrugated sheets in the manufacture of composite flooring is carried out in each wave to create greater strength for the base. The optimal number of supporting columns reaches three. Two supports may not withstand the load of a reinforced concrete monolith, which leads to deflection and deformation of the entire structure. By making composite slabs of a metal profile base, the ceiling surface of a given color is initially created . The variety of polymer coatings provides wide design possibilities.
Types of removable formwork
Depending on the structural design and scope of application, there are several types of formwork systems. Let's consider the main ones:
- Sliding. Purpose – tiered concreting during the construction of multi-storey structures. A characteristic feature of this type of formwork is the ability to lift it upward using electric motors as the concrete hardens.
- Perestavnaya. It is distinguished by its versatility and is assembled from metal panels. Structural elements are fixed using tubes and pins. After the concrete mixture has set, fasteners and panels are dismantled and can be used for repeated pouring. All mounting holes must be cemented.
- Hanging. Assembled from beams, racks and panels. The material used in the manufacture of shields can be plywood, steel or plastic. All panels are fixed to each other as tightly as possible and suspended on beams or racks. Suspended formwork has become widespread when pouring attic and interfloor floors, as well as staircases.
- Volumetric. It was specially developed for concreting large-sized horizontal structures. Often used for simultaneous pouring of ceilings and walls or gutters. The formwork is moved after the concrete has hardened using wheel supports or rollers. To construct the foundations, volumetric formwork with U-shaped sections is used.
- Block forms. It has the form of a frame structure used for casting products in both vertical and horizontal planes. As a rule, block molds are used to manufacture elevator shafts, volumetric wall elements, columns and other related structures. Dismantling of this formwork is carried out using jacks.
Please note that formwork systems are also usually classified into small-panel and large-panel.
Small panel ones are suitable for pouring small monolithic concrete structures. Due to their small weight, they are easily assembled by hand without the use of special equipment.
Large panel formwork is used in the construction of large structures. During its assembly, construction equipment is used. It is designed for high mechanical loads. Often the overall dimensions of the panels correspond to the dimensions of the concrete structure.
Large panel removable wall formwork photo
Small panel removable wall formwork photo
Corrugated sheeting for floor formwork - use when creating a flat roof
Load-bearing corrugated sheeting is used as formwork when installing interfloor ceilings and flat roofs. The profiled sheet used for these purposes has a profile height of more than 44 mm and is usually reinforced with additional stiffeners to increase its load-bearing capacity.
When installing flat roofs, a layer of vapor barrier, insulation and waterproofing is laid on the surface of the corrugated sheet. After this, a slope is made from a reinforced cement screed. Such roofs are often used in the construction of large-span entertainment and sports buildings, as well as large shopping complexes. In addition, multi-apartment residential buildings also almost always have a flat roof, which is associated with the need to maintain ventilation shafts and other structural components of the house.
Flat green roof for a residential building
For individual residential construction, a flat roof is used much less frequently. Basically, such projects are associated with the organization of a small recreation area on such a roof, including green spaces. In this case, the use of corrugated sheets for floor formwork is doubly justified - the high load-bearing capacity of corrugated sheets allows you to easily withstand not only the mass of land and green spaces, but also water bodies such as artificial ponds or swimming pools.
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What characteristics should removable formwork have?
- Low adhesion to concrete mixture. Those parts of the structure that will be in direct contact with concrete should have as low adhesion as possible. Otherwise, the formwork will be difficult to remove and clean for further use.
- High strength. All structural elements must withstand increased mechanical loads. A large mass of concrete can deform the formwork. This, in turn, threatens with unnecessary financial costs and loss of time.
- No gaps at joints. All structural elements must fit perfectly against each other to avoid leakage of the concrete mixture. Gaps should be repaired prior to the pouring process.
- Reliability of connections. In removable formwork, the strength of the locks and their simplicity are extremely important. This affects the reliability of the entire structure and the speed of its assembly.
Some basic solutions
It is not so important what material the formwork is made from; it is advisable to comply with some requirements when making it yourself, namely:
- The manufactured frame must have sufficient strength and be well fixed in the desired position.
- All elements of the prefabricated structure must be adjusted as accurately as possible. In this case, only minimal gaps are allowed. This applies to the frames being built not only for the foundation, but also for the walls.
- The structure over its entire area must withstand the maximum loads that the liquid concrete solution will exert.
- It is desirable that the removable structure has the least adhesion to the concrete solution.
- If you plan to use the frame more than once, then it should not have any deformation or damage.
Scope of application
The scope of application of removable formwork in monolithic construction is practically unlimited. Depending on its design, craftsmen have the opportunity to create concrete products of a wide variety of shapes and sizes. As mentioned earlier, with the help of formwork systems you can pour foundations, erect walls of buildings in multi-story construction, make floors, columns, and stairs. Also, formwork is indispensable in the construction of tunnels, monolithic parts of pipelines, as well as the formation of objects of complex curved shape. For example, the domes of churches and mosques.
It is worth noting that when carrying out work in the cold season, formwork systems are able to protect concrete from the destructive effects of low temperatures.
Removable frame option
This type of formwork is used more often. In this case, the structure is dismantled immediately after the first signs of setting of the concrete solution appear. Using removable frames, you can form not only the foundation, but also regulate the construction of walls for multi-story buildings and many other building structures.
Next, it’s worth considering what materials can be used to make such frames:
- Solid wood of various species.
- Compressed wood, or as it is also called plywood.
- Metal sheets. Most often, steel is used in this case.
- Aluminum molds or sheets.
- A variety of combined materials.
- In addition to the above materials, recently, quite often formwork is made of polyvinyl chloride.
Important:
Metal sheets are used to form the frames of massive structures. In this case, for large-sized structures it is more advisable to use a monolithic frame to avoid any further difficulties.
To build the foundation, wooden formwork is most often used, which is quite easy to make with your own hands. Boards, bars or plywood can be used here.
Pros and cons of removable formwork
One of the key advantages is the possibility of repeated use. This makes dismountable formwork systems very popular among professional builders, as they can significantly reduce the construction budget. High-quality systems can easily withstand 100-200 or more operating cycles!
An important advantage is the ability to cast concrete products of complex geometric shapes. In particular, removable formwork is an ideal option for the manufacture of stairs, columns, tunnels, arches, etc.
Thanks to a well-thought-out fastening system, assembly and dismantling of the formwork takes a minimum of time. Due to the low adhesion of concrete to structural elements, cleaning them before reuse is quite simple.
Formwork systems are manufactured in accordance with GOST. This allows you to easily replace failed structural elements, increasing the service life of the formwork as a whole.
In the case of professional use, removable formwork has no disadvantages as such. The fairly high cost more than pays off in the long run. Some difficulties may arise during the transportation and installation of large-panel formwork. It requires the use of specialized equipment and additional costs for transportation.
How to make sliding mobile formwork yourself? Diagrams and videos
The use of sliding formwork allows you to quickly pour a monolithic reinforced concrete structure with good performance characteristics; the maximum effect is achieved when concreting buildings without openings and protrusions. This technology is valued for its lack of seams, the ability to fill complex architectural forms, and the reduction of work time, money and labor costs. The main area includes industrial and civil construction, but a number of techniques are also suitable for individual developers; the simplest options are easy to do with your own hands.
Installation of removable formwork
The design and installation of removable formwork must be carried out by professionals. This procedure has a lot of subtleties and nuances. In general terms the whole process looks like this:
- Selecting the type of formwork depending on the specific construction task;
- Preparation of all components (boards, racks, fasteners, etc.);
- Preparing the construction site for the installation of formwork;
- Installation of shields. Be sure to check that there are no gaps at the joints. Otherwise, concrete will seep through them, which will lead to defects in the poured structure.
- When pouring massive thick-walled structures, the formwork should be further strengthened.
- After the concrete mixture has hardened, the formwork is dismantled, cleaned and lubricated.
Technology for erecting monolithic structures using sliding formwork
Mobile structures are successfully used in the construction of deeply buried strip foundations. Concrete preparation is made on the underlying layer, then a reinforcement frame is erected on it, around which sliding formwork structures are installed. The technology for constructing the foundation walls of a strip monolith is the same as for the construction of load-bearing walls of a building. After installing the formwork structures, the concrete mixture is poured around the reinforcement frame. All layers of concrete 200-300 mm thick are compacted with electric vibrators. After the concrete reaches its initial load-bearing capacity, the panels are driven vertically by hydraulic lifts.
Vertical guides in the form of metal rods are fixed in the foundation. The formwork panels are moved along these guides. When constructing walls, the initial height of the rods is 6 meters. When building a house of greater height, the rods are increased.
Watch a video of how this type of formwork is used when pouring monolithic structures.
Walling
After installing the reinforced frame, layer-by-layer concreting of the formwork is carried out. Sliding formwork is poured along the entire perimeter of the building at the same time. When the concrete acquires its initial degree of strength, the enclosing structures are moved upward at a speed of 2.5-3 cm every 10 minutes.
Work on concreting the walls is ongoing. During the continuous raising of the panels, reinforcement is made and internal formwork elements are installed for window and door openings. During the day, during normal operation of the formwork system, walls are erected to a height of three meters or more.
Concreting with sliding formwork is carried out only in continuous mode. In case of violation of the concreting rhythm, the monolith structure will not reach the design load-bearing capacity.
We recommend watching a video on how to level walls using this formwork.
Why do they not buy formworks, but rent them?
Firstly, because it is much more profitable. If you compare how much it costs to rent formwork with the cost of purchasing it, the difference will be 1 in 80 and even 1 in 100! If you are building only one house, for yourself, there is absolutely no need to overpay for something that will no longer be useful to you.
Although large construction companies also rent formworks. It seemed that it would be more profitable for them to buy them, but no. The fact is that all buildings (even those built using the same technology) differ in number of storeys, load on the foundation, architectural elements (some have square window openings, others have arched ones), etc. But, unfortunately, there is no universal system of supports and racks haven't figured it out yet. So even large players in the construction market have to resort to the services of landlords, since the purchase of formwork increases the price of the finished structure, which is impractical in conditions of high competition.
What determines the cost of renting formwork?
The cost depends on the manufacturer, availability of quality certificates, type of system (vertical or horizontal), material (steel, aluminum, wood), maximum permissible load, etc.
So, for example, vertical systems should be used for walls and arches, and horizontal systems should be used for interfloor ceilings and foundations. Vertical ones will cost less, horizontal ones will cost more.
The cost of rent also depends on the size of the advance payment, the method of delivery of the structure to your site (pickup is cheaper), and the rental period (the longer, the more profitable).
Therefore, the formwork rental price is always individual. Even if you come to a construction market or warehouse and point to any system, the seller will not be able to answer you with an exact price. The number of supports, racks, crossbars and other structural elements of the formwork, as well as the material for their manufacture, are determined exclusively by calculation (taking into account the load on the elements, the number of storeys of the building, the area of concreting, the thickness of the pour, etc.). Therefore, in order to get an accurate estimate, it is better to contact one of the specialized formwork rental companies and call a specialist to your site.
Formwork for the construction of house walls
Today it is no longer enough to build efficiently and beautifully; today’s construction business involves performing construction work as quickly and cheaply as possible. Capital turnover and the ability to interest the client in a quick result depend on this. Therefore, in the niche of classic stone buildings, brick is increasingly used as a facing material. Concrete casting and wall formwork make it possible to form a very strong and rigid frame of a one-story house in just a week. Whereas brick structures take twice as long to lay and at high costs for paying qualified masons.
Where is formwork used?
Formwork is a special structure that is designed to hold concrete while it hardens.
Therefore, it is not difficult to guess that the main area of application of formwork is the construction of a foundation. So, for example, when pouring a strip foundation, formwork is installed along its perimeter along its entire height (but not below the depth of soil freezing). The concrete solution lies smoothly and is securely fixed.
At the same time, the formwork also performs other tasks:
- Prevents cement mortar with additives from crumbling when hardening. That is, it maintains the shape of the foundation and gives it the correct geometric dimensions and shape;
- It also serves as additional protection for the foundation from the effects of precipitation, water, snow, wind and other aggressive environments.
If you fix the formwork so that it is on the same level with all structural elements, you can achieve a flat surface of the strip foundation and a zero level for the walls.
But the use of formwork is not limited to one foundation. Thanks to it, developers can quickly build monolithic concrete walls.
Using this technology, in fact, the entire process of building a house comes down to the fact that you just need to pour concrete inside the constructed wall structure. The formwork itself is assembled from ready-made sheets, boards or blocks directly on the construction site.
There are many advantages of this technology. Firstly, speed - such houses are built very quickly. Secondly, you can build monolithic houses using the formwork method at any time of the year. Even in twenty-degree frost. And thanks to the low thermal conductivity of the walls, the developer’s costs are reduced not only for heating, but also for air conditioning the premises in the summer.
But perhaps the most important advantage of monolithic technology is the low cost of construction. Thanks to the locking design of modern formworks, all blocks are assembled quickly, like a construction set. To build such walls, you do not need to hire large construction crews. And thanks to the low weight of the formwork, cranes and heavy equipment are not needed.
Installation of formwork is a fairly simple process. It does not require much experience in construction. However, people who have previously been involved in the construction of formwork do it faster and better than those who do not have such experience.
