It is evident, and all would agree, that the house should be strong, durable, built quickly and at a relatively inexpensive cost. In most cases, disputes begin on the choice of building materials. Which would be stronger, thermal insulated, warmer – wood, brick, concrete, or polymer-based materials? Which of them are considered environmentally friendly and which are not? Until recently, metal, steel in particular was not part of the discussion on the material for the construction of the frame of an individual house. However, the development of energy-efficient technology, the translucent structures based on steel beams are built today even beyond the Arctic Circle (Charlet and Thomas, 2013). Design engineers have found a way to reduce the heat-conducting ability of steel beams to the level of wood moldings. To do this within an extruded steel beam, the designers have made air pockets and inserted thermo-pads made of plastic, which prevent the rapid spread of the cold. The peculiar features of this structure is not only in the rapid cooling of the metal, but also the formation of condensation in winter. To remove we must install a certain ventilation system allowing to take the vapor out of the premises in order to prevent corrosion of the metal (Waite, 2000).
So ,how do we build a lightweight and durable steel frame housing and try to avoid corrosion, the formation of cold drafts and condensation? The answer to this question was found in the fifties of the last century by the Swedes. With the advent of high-quality insulation and vapor-permeable protective materials they developed a new concept of the construction of homes made of steel framing. Today, this techniques is known as the technology of construction of lightweight steel thin-walled structures. As a frame a thin-walled galvanized profile, similar to the one that is used for mounting drywall sheets, only larger in the cross-section and with a special perforation (it was called thermal profile) is used (Charlet and Thomas, 2013). The gaps between the frame struts are filled with mineral wool insulation or fiberglass. According to researches, the openings in the walls of the profile significantly reduce heat loss through the walls of the building due to the extension of the path of the heat flow and characteristics of the boundary properties of the slots having a complicated shape. In addition, the heat conductivity affects the thickness profile of the material. The thinner the steel, the less heat loss.
"But what about the problem of the" dew point?” you would ask. After all, when the temperature increases moisture will still show up." Indeed, the "dew point" is present in a wall construction of any building. However, it is important, where and how the water vapor is discharged. In hose with a steel frame the "dew point" is located inside the walls of the building, and the problem of condensation can be solved only with the well-designed system of ventilation panels. Firstly, they are protected from moisture, coming from within the house by an insulation film. Second, outside the frame is filled with vapor-permeable insulation, which freely releases the moisture contained in the outside panels, but protects the heater from weathering and wetting. Third, an additional clearance is vented between the film and the outer lining, which creates conditions for occurrence of air thrust. Air flow quickly removes water vapor (Riley, Cotgrave & Howard, 2008).
Another problem that cannot fail to excite the people who know physics is the high electrical conductivity of steel structures. However, a lightning strike or an accidental breakdown is dangerous if the metallic conductors are poorly grounded. If preventive measures to avoid the occurrence of potential differences in various parts of the metal have been made, then there is nothing to fear. To make life in a steel framed house more secure and safer is helped by a correct potential equalization system. The latter becomes an effective defense system - in the event of potential differences in various parts of the installation it levels them out (Waite, 2000).
How does this system work? All potential conductors of electricity in the building, including a metal frame, are connected to a common circuit and are grounded at several points. When the lightning injects an electrical discharge into the building it is transferred onto the earth without causing harm to people and equipment. In addition, finishing the house inside and outside with non-conducting materials eliminates direct contact with the metal frame. For wiring it is recommended to use double insulation. To improve the electrical safety of a steel framed house and to protect the equipment located it is usually a must to install surge arresters, circuit breakers and selective RCDs in switchboards.
The initial components of the are lightweight steel thin-walled structures are steel profiles having a cross section in the form of letter C, U, S and Z and made of galvanized steel with a thickness of 0.7 to 2 mm (Riley, Cotgrave & Howard, 2008). As noted above, the highlight of the supporting structure of the walls is considered thermal profile, in which the walls are cut through with multiple grooves. Because of this the heat flux path between the jumper grooves sharply increases whereas the flow area decreases (Green Home International, 2016). As a result, the amount of heat lost is substantially reduced. Unfortunately, the strength characteristics of the profile are weakened (including resistance to bending, twisting and longitudinal stability). Therefore, it is necessary to carefully think about the design and calculate the frame rigidity for the entire building. Specific elements, such as panel truss, hard drives overlapping the edge of the beam, fastener nodes in truss ceilings and roofs are used (Riley, Cotgrave & Howard, 2008). Thermoprofiles are combined with the conventional thin-walled profiles with a wall thickness of 1-1.5 mm. Since the metal plating treatment is carried out with hot-coating this provides a protective layer with a thickness of 20 microns with a longevity of up to a hundred years. Thermoprofiles are connected on site to design with special self-drilling screws (Riley, Cotgrave & Howard, 2008).
In a number of parameters the counterparts of steel framed structures do not come even close. A lighter construction can only be a thatched hut (Chiras, 2011). Thus, the weight of 1m2 of wall without the exterior cladding is in average of 53 kg; a construction truss with a span of 9 m weighs 70 kg. Due to the ease of completing all construction is carried out without the use of lifting equipment. These buildings do not need a foundation at the depth of 1.5-2 m - they perfectly stand on shallow foundations (tapes, monolithic slabs or bored piles). Application of shallow foundations allows to reduce the consumption of concrete by 50-80%, reducing the cost of construction (Chiras, 2011). Due to the lightweight properties of each element, dimensional accuracy, correct labeling and blueprints, a team of three to four people are in a position to put the house carcass with an area of 150-200 m2 in 2-3 weeks. For the installation of all the elements of the building you only need a set of cordless screwdrivers. Buildings built from lightweight steel can be one-and two-storey plus the attic floor, have a size of 12 meters in width and 90 meters in length, with a height of each floor not higher than 4.2 m. The buildings made from a steel structure are characterized by high seismic resistance and resistance to extreme wind loads (Riley, Cotgrave & Howard, 2008).
Now the whole structure is finished with wooden cladding with an insulating membrane. Cladding from wood is an energy-efficient solution, using the building material with zero thermal conductivity and high vapor permeability (PEFC, 2016). Wooden cladding helps to create a comfortable microclimate inside the building, and allows the structure to "breathe", which, in turn, prevents the formation of condensation on the walls of buildings and increases the service life of the building. With the help of wooden panels the whole structure can be given a presentable appearance, besides, wood is an environmentally clean material safe for humans (PEFC, 2016).
The addition of various additives and components provides a high-lining material that is resistant to moisture and ultraviolet rays. In the production of cladding panels the latest technology is used to provide the client with the following benefits (PEFC, 2016). Wooden cladding is durable, it has low thermal conductivity, it is resistant to change in temperatures, it is resistant to external destructive factors, in the case of frost wooden cladding retains its characteristics at temperatures down to -50 degrees Celsius, it is environmentally friendly; however, most important, the installation and its maintenance are as easy as can be.
Having discussed the benefit of the materials above, it is easy to see why this is a valid suggestion in the construction of a dwelling.
Reference
Charlett, A. & Thomas, C. (2013). Fundamental building technology. New York, NY: Routledge.
Chiras, D. (2011). The homeowner's guide to renewable energy: achieving energy independence through solar, wind, biomass, and hydropower. Gabriola, BC: New Society Publishers.
No author. (2016). Green Home International. Web. Retrieved from http://www.green-homeinternational.com/steel-frame-technology
No Author. (2016). EFC: Promoting Sustainable Cladding and Decking through Certified Timber. PEFC. Retrieved from https://www.google.com.ua/url?sa=t&rct=j&q=&esrc=s&source=web&cd=10&cad=rja&uact=8&ved=0ahUKEwiA_d2RuMrMAhUhIcAKHTciBpIQFghkMAk&url=http%3A%2F%2Fwww.pefc.co.uk%2Fsystem%2Fresources%2FW1siZiIsIjIwMTUvMDYvMjIvN3NiYmcxamR0NF9QRUZDX0NMQURESU5HX0JST0NIVVJFX1dFQi5wZGYiXV0%2FPEFC%2520CLADDING%2520BROCHURE%2520WEB.pdf&usg=AFQjCNFE7pgmY71fpD9EQYHLJutwAr_0Ww&sig2=tJjRaQxBXg2J4fhyNMYtsw&bvm=bv.121421273,d.ZGg
Riley, M., Cotgrave, A. & Howard, C. (2008). Construction technology. Basingstoke England New York: Palgrave Macmillan.
Waite, T. (2000). Steel-frame house construction. Carlsbad, CA: Craftsman Book Co.
