Prefabricated frame houses are in high demand due to low cost and accelerated installation technology. Obviously, these advantages come at the expense of a wide range of design flaws, such as mechanical weakness and short service life. On the other hand, such projects are not always designed for long-term use, but even in this case, not everyone is ready to put up with the shortcomings of the building, which affects comfort. The technology of a frame-fill house allows you to eliminate one of these disadvantages. We are talking about thermal insulation, and in some cases, strengthening the structure.
General information about backfill buildings
The technology is based on the principles of the Canadian prefabricated frame method of building private houses. As a rule, these are one-story buildings of a small area. The construction process is carried out using a ready-made house kit, which includes all the necessary materials. The supporting structure is constructed according to the traditional scheme using frame racks. The fundamental difference between almost allframe houses is that walls and partitions do not perform the direct function of holding horizontal interfloor ceilings with the load placed on them. They serve only as building envelopes. In turn, the bearing function is separately transferred to the metal and reinforced concrete racks of the frame. Sheathing can be made from a variety of materials from chipboard or OSB sheets to brick and timber.
What is a filling structure? From the usual frame construction, it is distinguished by the approach to the thermal insulation device. The fact is that the walls of backfill houses inside have a cavity for filling with bulk materials. Actually, hence the name of the technology. If a standard frame house contains mineral wool with film vapor and water insulators in the wall structure, then sand (perlite), peat or sawdust acts as a heater in backfill structures. It is tightly rammed so that there are no voids left. The walls themselves are made with sheathing from boards or other panel materials used in frame-panel construction.
In general, we can conclude that the backfill building is a prefabricated structure, which is built from start to finish at the construction site, has a system of load-bearing racks and provides for laying loose insulation in the walls.
Requirements for backfill materials
The basis of the frame is formed by wooden supporting structures, which must be made of softwood lumber, dried in a dry room. Forelements that will be located in the area of \u200b\u200bthe foundation or basement (at a level below the ground surface or less than 25 cm above it) should also be subjected to antiseptic treatment. It protects wood from rotting and physical destruction.
According to SNiP 2.03.11., facing, finishing, roofing, insulating, sealing and other building materials for a frame house must also comply with local conditions of use.
Ecological requirements are taken into account separately. This is one of the aspects that distinguish the frame-fill house from conventional prefabricated panel buildings. It is the rejection of synthetic heat-insulating layers in favor of loose fillers that determines a higher environmental friendliness of the structure. The regulations also approve the rules for the use of board materials made of wood, which should not contain toxic inclusions like formaldehyde above 5 mg per 100 g. If they cannot be abandoned, then the material will have to undergo a preliminary detoxifying primer.
Often, asbestos-containing elements are also used in frame housing construction - in particular, in interior decoration. Such materials, when installed, must either be faced with glazed tiles, or covered with waterproof paints and varnishes. This treatment is required to protect against exposure to disinfectant solutions in household care.
Safety regulations
Features of the operation of prefabricated frame houses, among other things, are associated with fire hazards and low structural strength. Both factorsaccordingly, determine higher requirements for the prevention of similar threats.
As for fire safety, it is provided in two ways:
- Replacement or complete rejection of combustible or at least flammable materials in the main structure. The same OSB sheathing burns quickly, transferring the flame to load-bearing panels and walls, if they can, in principle, burn. Particular attention is paid to insulators and insulating filler. If wood chips or sawdust are used, the sheathing must be non-combustible.
- The second way to increase the fire safety of a backfill house on a wooden base involves the creation of protective fire-resistant barriers. These can be special impregnations for the wood structure, and quite functional structural elements. For example, there are modifications of drywall sheets and bas alt wool that do not support combustion and serve as full-fledged layers of interior cladding.
Rules for ensuring the mechanical strength of the house
According to experts, the mechanical strength of correctly erected frame houses allows them to serve for more than 50 years. Structural reliability is also maintained in a variety of ways. As already noted, much will depend on the carrier system of racks. These are vertical and horizontal elements that form power belts in the form of lower and upper harnesses. Also, lintels above the openings are introduced into this system. Racks should rest on the floor of each floor, distributing the load over the entire area.
Strengthen the design and through the inclusion of more durable materials than wood. For example, there is a technology for a combined brick-fill house, which uses one or more brickwork. Actually, the masonry acts as a supporting strapping belt, which increases the load capacity of the base. But it is important to consider that a brick with a monolithic structure will not allow proper thermal insulation to be performed - moreover, cold bridges can form at the junctions. An alternative option would be the use of polystyrene blocks. These are modular hollow wall segments that can be filled with any bulk insulation.
Establishing the foundation of a backfill house
The site for future construction is being cleared for a strip foundation. Debris, stones and vegetation are removed along with the roots. If there is an anthill in the site area, the contaminated soil is replaced to a depth of up to 30 cm. The soil structure at the bottom of the pit should maintain an even geometry. If it is planned to lay communications, then the contours of the trench are filled with dense bulk material, which is then rammed and concreted. Next, the width of the walls is determined. It is possible to build a backfill house with external and internal walls 20-50 cm thick. The specific value is determined by the number of floors with ceilings. Accordingly, for a one-story house, walls with a thickness of 20-30 cm are calculated, and for a three-story house - about 50 cm.
Foundation soles are arranged for load-bearing columns. The step between them is calculatedindividually - depending on the number of floors, the structure of the carrier system and the nature of groundwater. How to make a backfill house on a stepped foundation? Such structures are organized on slopes so that the length of the horizontal section is at least 60 cm. It is also possible to use a columnar foundation. In this case, the piles are located along the perimeter of the supporting frame with a step of 2-3.5 m.
Installing the frame
The supporting structure is formed by pillars, columns and pilasters. The calculation of this system takes into account the load on the floors, as well as external influences such as wind. To provide the backfill house with load-bearing elements of the frame should begin from the basement. At the level of the basement, racks with internal walls are placed, which in this case also perform a load-bearing function, supporting the first and most important floor.
The columns are fixed in the center of the foundation. External rods are additionally connected to the floors with anchor bolts. Usually they use metal and reinforced concrete structures, but sometimes the introduction of wooden poles is also allowed. In such a system, it is important to provide for the isolation of the wood material from the concrete structure. This is done with plastic wrap. Metal poles are indispensable elements of the supporting frame of two-story backfill houses. With your own hands, you can also make pillars of stone or brickwork. The normative parameters for such structures in width and depth look like this: 29x29 or 19x39 cm.
Pilasters can also be used as an addition. They are arranged in the basementwalls, the thickness of which is not more than 14 cm. Pilasters are provided at reference points relative to the floor elements. Fastening is carried out over the entire height at the junction with the walls of the basement.
Features of wall construction
For the walls, a frame power base is also created in the form of vertical racks and auxiliary horizontal support nodes. Jumpers are installed above the openings, and strapping belts are mounted throughout the entire carrier system of columns - at least from above and below. Sheathing of the walls of the backfill house is made of rigid sheet or slab material. The panels must comply with the loads from the own weight of the floors of the house and from the wind. If rigid plating is excluded, then additional reinforcement with diagonal bracing or bracing will be required.
It is advisable to fill the walls with insulation in warm weather, so that the risks of waterlogging the material are initially minimized. In the filling process, it is important to exclude voids, openings, gaps and underfilled areas. Such defects affect not only thermal conductivity, but also structural integrity. Wall niches can be provided with sawdust, arbolite, sand, expanded clay, etc. The cheapest and most practical option is to build a filling house from sawdust, which can be obtained free of charge and in the right amount at sawmills. Another thing is that pre-processing of the material is also required. Experts recommend that the sawdust be dried well, compressed, and also mixed with cement, which will eliminate the riskswaterlogging of the filler during the operation of the house. If the task is to increase the structural reliability of the walls, then it is better to use an adhesive binder instead of cement. It is advisable to choose compounds with antiseptic and refractory properties.
Exterior decoration of the house
Since the walls are mainly designed for enclosing, and not for load-bearing function, it is important to initially provide a solid foundation for attaching the outer decorative material. As a rule, this function is performed by a crate - a structure made of wooden planks and bars, which is mounted on the main wall cladding panel and serves to perform the subsequent fixation of the cladding. The following materials can be used as finishes:
- Wooden board. It can be wide slats, and lining with locking grooves. Reviews of backfill houses with this design emphasize the advantages of natural texture, environmental friendliness and ease of installation. You can mount a board on a wooden crate with ordinary nails with putty and biological treatment.
- Siding. It is also an easy-to-install material, which is plastic, wooden or metal panels. It is more practical to use aluminum sheets, which weigh a little and look quite presentable. The only drawback is that aluminum is easily deformed, but it is also quite easy to restore it.
- Block house. Imitation of the textured image of a classic log house on a metal base. ATessence, a combination of siding and boards - semicircular sheets are fixed to the crate with hardware and interlock with each other through a butt-groove connection.
Repair work
Because the home is largely made up of natural wood components, there will be occasional need to repair areas that have been biodegraded. This mainly applies to wall cladding and internal insulation. How to restore the structure of an old backfill house? Damaged areas, subject to the presence of a small affected area, are literally cut out with a chainsaw. During the cutting process, it is important to avoid damaging the columns and studs associated with the wall structure. Mortgage timber, board or slab material are replaced with new analogues with sealing. If the entire segment was exposed to decay, it should be removed completely without separate clippings.
If there are signs of damage to the internal filler of the walls (smell of decay, moisture coming through, softening of the structure of the wall material), then the sheathing does not have to be dismantled. The same sawdust is replaced with a new loose insulation, but all foci of decay or damage of a different nature in the wall niche should first be eliminated. In this part, the repair of the backfill house will consist of a major antiseptic treatment of the sheathing surfaces from the back. By the way, to initially exclude direct contact between the filler and the wall surfaces, you can lay the material in thick plastic bags, and then place them tightly in the niche of the structure.
Advantages of Technology
As a kind of frame building, a house with loose wall filler gives a lot of advantages in terms of construction organization. They are expressed in the optimization of work processes, the reduction in the cost of materials, the increase in the speed of construction, etc. Even compared to traditional wooden houses, this method will have noticeable organizational advantages. Against the background of other frame buildings, the pros and cons of a backfill house will also be very noticeable. Loose fill, unlike mineral wool, polystyrene foam and other synthetic insulators, allows you to provide an environmentally friendly and cheap thermal barrier.
Flaws of technology
You should also start with the general features of frame houses, which also apply to infill buildings. The disadvantages will include low reliability, limitations in the implementation of various add-ons and high fire safety requirements. Like the advantages of a backfill house, its disadvantages are largely determined by the technology of using bulk insulation. Organic fillers are more susceptible to biological degradation, combustion and are often eaten by insects. In addition, they are fertile ground for the life of rodents, which can cause significant damage to the structure. Accordingly, there are additional requirements for the maintenance and maintenance of the structure of the house, which will include the need for regular flame retardant, disinfectant and biological treatment.surfaces.
Conclusion
With all the limitations and shortcomings, infill structures allow you to build energy-efficient and comfortable modern housing. For a relatively small amount, you can build a completely functional and durable sawdust house of 1-2 floors. Another thing is that it will be necessary to maintain the named operational properties by special measures. They relate to the care of sensitive construction materials, the main of which will be wood. Numerous impregnations, primers and protective coatings help to increase its working life.
