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The construction of buildings on a metal frame has been practiced for a long time, but they mainly built industrial and technical premises, buildings of shopping centers, etc. Application in private housing construction was limited by the high thermal conductivity of the metal: heating bills would be unrealistic. Manufacturers solved the problem by making the so-called thermal profiles, which, paired with modern heaters, make it possible to get a warm house. If you are looking for an inexpensive, reliable house that is built in a short time, a metal frame house may be right for you. It has a low cost – two times lower than brick, assembly is fast, the service life of the factory frame is 70 years.
The technology is very flexible: any house you like can be adapted to a metal frame. First, a frame plan is drawn up, the type of finishing materials is determined (only your wishes affect). Further, the developed project is processed by a special program that breaks everything into components, gives a list of elements with all the parameters. Profiles of the required size are manufactured and marked, bundled, packaged, delivered to the construction site. In short, this is the entire technical process – from project development to the start of assembling a frame house from metal profiles.
Advantages and disadvantages
This technology is becoming more and more popular in European countries (including northern ones), Canada and America. And all because steel does not rot, it is not eaten by insects. A metal frame structure weighs several times less than a house made of wood (twice), and even more so, it is lighter than houses made of brick and other similar materials. The light weight of the building means lower foundation costs, since its parameters depend on the load, which further reduces the cost per square meter of development. Usually, pile, pile-grillage or strip foundations are placed under such houses. On average, one square of the area costs 4-5 thousand rubles (excluding the cost of finishing materials).
The technology by which a metal frame house is built is called light thin-walled steel structures, or LSTK for short. Lightweight does not mean fragile. Houses built using LSTK technology can withstand earthquakes of magnitude nine. But this applies to buildings no higher than 3 floors.
Another advantage of a steel frame over a wooden frame is that it is strong enough to withstand heavy roofing materials. If you decide to use ceramic tiles – please. Only its weight must be taken into account when calculating the parameters of the foundation.
The very design of the wall cake is almost the same as that of wooden ones. The whole difference is in the material used for the frame and the method of assembly.
What about cold bridges? Manufacturers claim that the problem is solved. Modern thermal profiles, from which private houses are built, have sections arranged in a checkerboard pattern. They prevent through freezing of structural elements.
And although thermal profiles really work, all the same, such a house is colder than a wooden frame house. However, the problem can be solved by making high-quality insulation. With the correct execution of the “pie” of insulation with all membranes (windproof, vapor-permeable from the outside, vapor barrier inside), the metal-frame house will be warm and no more will be spent on heating than in the so-called “warm houses”.
For insulation, you can use any modern insulation – mineral wool, polystyrene foam, extruded polystyrene foam, foamed glass, ecowool. Foam glass has the best characteristics, extruded polystyrene foam is slightly worse. But they have a solid price, although the required thickness is several times less than that of mineral wool. As a result, the cost of insulation are comparable.
The most optimal combination of qualities and prices for mineral wool. It is more convenient to work with basalt. She also has good features. Fiberglass is also good in terms of characteristics, but it is difficult to work with it. Slag wool is the cheapest, but it is very afraid of getting wet; when using it, it is necessary to install a ventilated facade.
For the above reasons, from the whole variety, I most often choose basalt wool. It fits well into the frame, has good thermal insulation properties, is relatively inexpensive, and is also a good soundproof material, which is important for this technology.
What is a metal frame house made of?
LSTK elements are made of durable structural steel by cold stamping. The sheet has a protective zinc covering from 18 to 40 microns thick. Some factories make structures from hot-dip galvanized sheets. Such elements are more expensive, but they are also more durable.
The thickness of the sheet from which they are formed is from 0,7 mm to 2 mm. The choice depends on the required bearing capacity of a particular element. There are the following types of profiles.
The following types are most commonly used.
There are also special floor and ceiling beams. The truss system of the house is made up of similar elements. The elements are connected to each other by bolts, self-tapping screws, riveting, contact welding can be used.
Now about the quality of components from different companies. There are about a dozen factories in Russia. Everyone’s quality is different. Therefore, carefully look at the quality of galvanizing, metal bending. There should not be any, even the smallest, traces of rust anywhere. In general, even the best “our” profiles are significantly inferior to imported ones. It’s a shame, but it’s true.
Assembly order
From the factory, all material comes packed in packs. Each part is marked, the same marking is present on the working drawings. The frame of the LSTK house is being assembled as a constructor: everything is ready, even holes for hardware are stamped. Put the parts in place, align the grooves and install the fasteners. From the metal-frame house is assembled in exactly the same way as from wooden bars. If we outline the stages briefly, step by step everything looks like this:
- The lower trim is fixed on the finished foundation.
- Corner posts are exposed and fixed.
- Intermediate racks, struts and struts are installed between them.
- The top harness is installed.
- Floor beams are installed and fixed.
- If there is a second floor, its frame is assembled.
- The ceiling is installed.
- The rafter system is assembled.
- Works on insulation and waterproofing of the roof are underway.
- The crate is assembled under the roofing material.
The truss system of a metal frame house is assembled from the same elements.
The frame of the steel house is ready. All that’s left is insulation and finishing work. It is a remark: no matter how much you want to save money, the crate should also be assembled from metal. The same expansion coefficients are exactly what contributes to the high strength of such structures. When joining metal and wood, this cannot be achieved: the fasteners gradually weaken. This is especially critical in regions with high seismic activity. But even in calmer regions, there is little joy from rattling finishes.
Can you build it yourself?
If we are talking about how to assemble the parts that came from the factory into one design, then easily, but with assistants. All work consists in finding the right part and installing it in the place indicated in the drawings. Difficult at first, then get used to it.
If by “do-it-yourself construction of a metal-frame house” they mean welding it from a profile pipe, then this is an ambiguous matter. If you are going to build a small country house, then there are no questions: the frame can be installed according to the same principle as a wooden one, and for a one-story building, 80 * 80 mm pipes are enough for corner posts, and you can take less for intermediate ones. But the installation step is still dictated by the insulation: the distance in the clearance should be 58-59 cm (slightly less than the standard width of mineral wool).
The only thing to remember: when using a profile pipe, cold bridges will be required. Then the insulation itself will need to be done in several layers, blocking heat leaks, which will solve the problem. One layer is traditionally placed in a spacer between the uprights. The cross section of the profile pipe is far from 200-250 mm, which are necessary for warming a house in the Moscow region (for mineral wool). Therefore, a transverse crate is arranged under the missing layers (on one or two sides – decide for yourself). It turns out that between the racks the insulation is laid vertically, and along the crate – horizontally. Cold bridges have become much less.
From the side of the room, the insulation is closed with a vapor barrier membrane (it should not let moisture into the insulation). From the side of the street, a windproof vapor-permeable membrane with waterproofing properties is fixed on it. It performs three functions at once:
- protects from the wind
- prevents condensate or accidentally falling precipitation from getting into the insulation,
- removes steam from the heater, which still penetrates there from the room (despite the vapor barrier).
Only with such a cake and the presence of a ventilation gap between the outer membrane and the finishing materials can you be sure that the insulation will not get wet. Only in order for the ventilation gap to work, ventilation holes are also needed at the bottom of the wall and an unhermetically sealed outlet under the roof from above: the air flow between the exterior finish of the metal frame house and the windproof membrane must pass without encountering obstacles.
For inspiration – a video that shows the process of welding a country house from a profile metal pipe. For those who know how to cook metal, it will not be difficult to make a metal frame house with their own hands from a pipe.
Read about what else you can quickly build a house from here.