The development of domestic frame housing construction does not stand still. Having thoroughly mastered standard American and European approaches to frame construction, companies and private associations are beginning to offer the consumer something more modern. Thus, frame technologies of DOK (double volumetric frame), as well as cross, 3-D frames, from double racks, etc., have appeared on our market.
Of course, such a wealth of choice is only a plus for a potential developer. But at the same time, many questions arise about the feasibility and optimality of this or that method of housing construction. Let's try to understand the advantages of complex frames, as well as in what cases they should be preferred.
Why complicate standard frame house designs?
It would seem that in the technologies of American-Canadian and European (Norwegian, German, Finnish, etc.) masters, honed over centuries, everything has already been taken into account to the smallest detail. Their designs frame houses differ:
- Reliability and durability. In America, for example, with its powerful hurricanes, it is not always possible for the elements to seriously damage frame structures, some of which have been standing for more than 100 years.
- Excellent thermal efficiency. It’s hard to argue with this, because it’s not for nothing that these houses are found everywhere in the coldest regions of Canada or Scandinavia.
- Profitability of projects. Minimizing investments in construction is noticeable in all its issues - from labor costs to the purchase of materials.
So what went wrong if the technology for building frame houses, established over many years, suddenly began to be widely modernized again? After all, even the emergence of more efficient materials, for example, mineral wool or foam plastic to replace clay, straw, sawdust or reeds did not introduce fundamental innovations in the technical process. The main reason should be sought in a significant increase in the cost of energy resources, environmental problems, and therefore in a changed approach to heat conservation issues.
What is wrong with single frame systems?
To answer this question, we first turn to the cornerstone parameters used in thermodynamic calculations building structures– thermal conductivity coefficients of materials. The higher they are, the more intense the process of energy transfer (heating, cooling) through the thermal circuit enclosures occurs. For a wall or ceiling of a house with wooden frame The thermal conductivity of insulating fillers and supporting structures is of key importance. The former are usually represented by mineral wool, ecowool, and expanded polystyrene, the latter by softwood boards.
Let's look at the average thermal conductivity coefficients λ (W/(m*°C)) of these materials at normal humidity:
- stone wool – 0.043;
- glass wool – 0.044;
- expanded polystyrene (PSB, PSB-S) – 0.041;
- extruded polystyrene foam (EPS, XPS) – 0.03;
- ecowool – 0.04;
- pine (across the grain) – 0.14;
- spruce (across the grain) – 0.29.
Comparing, for example, stone wool and pine boards, we see a difference in thermal conductivity of more than 3 times, not in favor of wood. So, in winter through the skeleton frame house The outflow of heat to the outside will occur much more intensely than through the heat-insulating filler. Thus, in relatively thin frame enclosing structures, wood becomes a cold bridge.
What does this entail in practice? Firstly, additional heating costs. Secondly, there is a risk, especially during periods of severe frost, of the formation of dew point conditions in the areas of the frame elements. And this already threatens the wood with moisture, which directly affects the durability of frame houses.
How can you improve the performance of frame structures?
Increased heating of the premises will help get rid of condensation. In fact, this is how, in many respects, the problems of thermal comfort for residents were solved in the past. In the most severe frosts, you could walk around the house undressed, and few people had ever heard of condensation on the walls. Now such an approach is an unjustified luxury. Therefore, frame house builders are looking for all sorts of ways to reduce heat loss, in this context by increasing the thermal resistance of the enclosing shells. For this:
- advanced thermal insulation materials are used;
- the thickness of parts of the thermal contour of the structure increases;
- Cold bridges are eliminated (by design and installation methods).
Effective thermal insulation
In any modern frame technology for internal filling external walls and ceilings, they try to give preference to materials with minimal thermal conductivity coefficients. Today they have fairly effective values, and their qualitative improvement is not expected in the foreseeable future.
Thermal insulation products should be chosen from a range of well-established manufacturers. This includes, for example, basalt insulation Paroc or Rockwool, films for vapor barrier or wind protection Yuta. Superdiffusion membranes of the Tyvek brand from DuPont, unique in their properties, have received particular recognition from domestic consumers.
Does thicker mean warmer?
In general, this is true. Just look at the basic formula for calculating the thermal resistance R ((m 2 *°C)/W) of a homogeneous material with a layer thickness σ (m):
It follows from the expression that the thermal resistance of the enclosing structure will increase with increasing width of its cross-section, as well as with the use of materials with lower thermal conductivity coefficients in the structural pie set.
As an example, we will make a rough estimate of the thickness of the thermal insulation layer for insulating the wall of a house built using frame technology. Rough because a real thermotechnical calculation takes into account a larger amount of data. We must satisfy the condition R o σ=3.13*0.044=0.138 m or 138 mm. In practice, taking into account cold bridges, installation errors and safety factors, we get at least 150 mm. And yet there remains a risk of local hypothermia of a single frame, especially in the coldest periods, leading to condensation in the area of wooden posts and lintels. Therefore, in order not to affect the durability of the frame house and to guarantee a “warm” wall over the entire surface, its thickness is increased to 200-250 mm. The specified parameters of the thermal circuit of a residential building are developed based on the operation of a full-fledged modern heating system, endowed with a specific heat output of 60–100 kW/m2. However, today in the design of not only frame structures, but also other types of buildings, there is a desire to get closer to the ideal of thermal efficiency. Engineers and installers are trying to create a so-called “passive frame house”. This is a structure with such insignificant heat losses that no energy is specifically spent on maintaining thermal comfort in it. To heat the internal volume of a passive house, the heat generated by the human body, electrical appliances, and coming from outside with sunlight through window glazing is sufficient. Of course, achieving such a high efficiency in the process of heat saving is possible only by implementing entire complexes of design solutions. They concern special energy-saving windows, an optimized ventilation system with heat recovery, and many other issues. However, key importance in a number of improvements in the thermophysical properties of a building is given to increasing the thermal resistance of walls and ceilings by creating reinforced frames with wide cross sections. In theory, the width of their sections can approach a meter in size, which in practice can complicate and unjustifiably increase the construction time of a frame house, making it too expensive. Therefore, in order to create a close analogue of a passive house (with heating costs of about 15 kW/m2) with investments that will pay off in the foreseeable future, its enclosing structures (for the central zone of the Russian Federation) must contain a layer of effective thermal insulation with a thickness of: But even when creating such thermal shells using single-frame technology, many questions arise. Firstly, as the thickness of dry planed timber increases, its specific cost and scarcity increases. Secondly, structural elements made of wood through the entire width of the section, in any case, remain areas with relatively high heat losses. Thirdly, various installation difficulties accumulate that can significantly worsen the calculated thermodynamic parameters of the structure. They relate to high-quality fastening and distribution of thermal insulation throughout the volume of the wall (floor), tight fit of rows of racks and their node connections, as well as other practical issues. Cross frame, double frame, DOK and 3-D help solve these issues. This is the simplest attempt to avoid through cold bridges through the entire end part of the wood of wall studs or floor joists. The figure shows the paths of heat outflow from the room through the conventional and volumetric cross frame of the house, as well as the most cooled zones that form in this case. Along the width of the structures (top view), with their same thickness, the length of the heat transfer sections does not change. However, if you look at them from the front, the difference in the areas of the cooled zones becomes obvious. Thus, with the same thickness of the enclosing structures and insulation in them, the double cross volumetric frame, in comparison with the usual one, allows: For example, the assembly of a structural skeleton for laying insulation with a thickness of 150 mm can no longer be carried out on the basis of racks from a 50 * 150 mm board, but on the basis of a 50 * 100 mm board (racks) and a 50 * 50 mm bar (horizontal frame). The double frame house scheme, patented in the West, using DOK technology - its promotion on the domestic market is carried out by the Nanosphere group of companies - can provide even higher energy efficiency and strength of the walls of the structure than when installing a cross frame. The feasibility of its use may be caused by the need to lay thick layers of insulation in the external and internal parts of the enclosing structure. If you resort to a cross pattern, the load on the vertical posts will be too high. Therefore, the second frame row is also assembled from vertical elements, but with the cells offset relative to the first. After uniform laying of the insulation, cold bridges are mainly formed only through the contact zones of the stud/lintel between the outer and inner layers. The area of local supercooled zones turns out to be approximately the same as in the case of a cross frame, which is clearly shown in the diagram below. However, by increasing the cross-section, the heat outflow paths are lengthened, which means heat loss through these areas becomes lower. As a result, wooden frames using DOK technology guarantee all the same advantages as cross ones, but at the same time provide higher strength to the enclosing structures. Another structural modification of the standard technology for constructing frame houses. From the diagram it can be seen that in the 3-D system there are completely no paths for through heat outflow. Heat exchange through the supporting skeleton is no longer carried out in a straight line, but along a more extended broken line. It passes through two posts and a horizontal crossbar of the intermediate frame. The Larsen frame system, just like the volumetric frame technologies discussed above, allows you to create external thermal shells of significant thickness. Its development is credited to Canadian John Larsen. In 1981, he proposed a slight departure from the traditional concept of monoelements made of solid wood (boards, timber) for assembling the skeletons of load-bearing structures of frame houses. His technology made it possible to imagine a wall stud or floor beam as a truss made up of boards (belts) and fragments of plywood or OSB (lattice braces). The original width of Larsen wall studs is 30 cm, but in practice it is taken to correspond to the thickness of the insulating layer. Trusses can be assembled using a similar scheme, in which the tie plates are replaced with lintels and struts made from boards. This modification is especially justified for load-bearing elements of wide walls. A logical question, since multilayer structures provide so many benefits to the consumer. However, in the foreseeable future there is hardly any point in abandoning the traditional single systems that have been proven for centuries. The fact is that frame technologies have a solid arsenal of correct solutions. Each of them must be selected based on an analysis of many factors: comfort requirements, acceptable initial investment volumes or payback periods, etc. For example, if a house is being built in a region with a mild climate or you are not afraid of its energy losses at the level of 60–100 kW/m2, compensated by standard autonomous heating, then it will be more expensive to deal with various volumetric frames. On the other hand, standards for thermal efficiency of building envelopes are gradually becoming more stringent. They are reviewed on average every 5 years. Therefore, if you want to keep up with the times or “not pay at all” for heating, then the frame house technology is DOK, 3-D, etc. - everything is yours. However, when choosing such non-standard solutions, you should consider that: These factors affect the return on additional investments in construction, which may well take 10-20 years. You should not forget about this when deciding what type of frame to choose for building your home.
Frame house construction has been known to mankind for more than one millennium. In Russia, with its severe frosts, houses were often built from thick logs. However, after the civil war and devastation, we adopted the cheaper Scandinavian experience of prefabricated panel houses. But over time, such natural construction faded into the background for us. Today, frame technology in Russia is experiencing a rebirth. Over the course of half a century, it has gone through a long evolutionary path; a modernized version has appeared, called “DOK” (double volumetric frame). The USA and Canada are considered its homeland, and the reason for its appearance is an attempt to eliminate some of the shortcomings of the traditional version. When using the classical scheme, residents of the coldest regions noted the tendency of the structure to internal temperature changes. This was due to the fact that the materials used in conventional frame construction have different thermal conductivities. As a result, so-called “cold bridges” are formed at their joints. This leads to the formation of condensation and, consequently, to a decrease in the strength and durability of the building. To solve this problem, DOK technology was developed; wooden houses of this design have the following features: Turnkey frame houses using DOK technology are offered at the lowest prices by the Dachny Season company. Frame houses DOK While some are sorting out the pros and cons of new technologies and advanced solutions, others are already successfully enjoying them. The unconditional benefits of innovations, of course, can be very doubtful, but this in no way applies to DOK construction. Let's look at how this technology is used in our realities in this review. DOK is a new trend in frame construction. A double volumetric frame (DOC) is a construction method made using two frames offset relative to each other. Nothing supernatural, it seems at first glance. However, it allows you to achieve results that were almost impossible before. Using the familiar frame method of constructing country houses and dachas, many had justified complaints about it - temperature changes in the room. And this, you see, is an unpleasant feature, especially when there is severe frost outside. This is explained by the fact that the materials from which conventional prefabricated houses are built conduct heat differently. Therefore, a cold bridge formed at the junctions of materials. Condensation formed, the structural strength and service life of the building decreased. This is why the DOK technology arose - in houses built using it, there can be no talk of condensation formation: Such a ratio of heat saving efficiency, frost resistance, strength, sound insulation and price was unattainable ten years ago. At the moment, the average price for 1 m² of a house built using DOK technology is 4 000
rubles According to generally accepted concepts, a house must have a foundation. In the case of DOK technology, everything is completely different. Of course, there is a foundation, but its role is played by reinforced piles installed in small increments. Firstly, this design is in no way inferior to the usual foundation, and secondly, it is an order of magnitude lighter than it. The patented technique requires certain dimensions and distances, strength limits of materials and special methods for drying timber for the frame. These documents are kept in safes like classified NASA materials. Waterproofing is laid on the foundation thus obtained, and a lining board is placed on top of it. The logs for the wooden floor are already attached to it. The frame itself is mounted not from laminated veneer lumber, but from a solid one, using a special drying technology. In fact, it consists of two cellular frames, shifted relative to each other and maximally reinforced with wood, timber for the frame. Both frames are fastened with special fasteners and components. Floor beams with a cross-section in the shape of the letter T are attached to the frame, which serve as an additional reinforcing element of the structure. Roofing work is carried out using conventional technology, characteristic of all frame houses. The beauty of any frame house is that it does not shrink, as is the case with timber. Therefore, you can begin sheathing the frame and other finishing work immediately after construction, rather than waiting a month for the wood to settle and dry completely. In principle, if you have free hands, then the work can be carried out simultaneously with the construction of the frame, which will further speed up the construction process. Another advantage is that you can cover them with almost anything. Plywood, boards, OSB boards. Unlike other types of wooden houses, the cladding begins from the inside, attaching the slabs to the frame with screws or nails. If you use plywood, then the process can be speeded up by using a construction stapler, but self-tapping screws are still preferable. After sheathing, a heat insulator is placed in the wall cavity. Here, too, you can use your imagination, but not too much. Polystyrene foam is not recommended for use in residential premises. Waterproofing can be done either with special rolled double-layer insulators or with construction foam. Foam will give the structure even greater strength. If everything went well, then we proceed to the outer cladding in the same way. The simplest and most economical option would be to use siding. To do this, we build a sheathing from a bar with a cross-section of 25x25cm with a step that corresponds to the size of the panels. We must attach a layer of hydro-vapor barrier to the sheathing, which provides additional protection from moisture and creates an air gap that promotes ventilation of the walls. Siding panels can be mounted on top of the protective layer. And yet, the holders of patents for DOK technologies never cease to assure that this exclusive method of drying wood will give the house an almost unlimited service life. Wait and see. But in any case, no matter what top-secret technology the country house is built using, it is designed to bring joy and tranquility. The history of the construction of frame houses goes back more than one decade. Over time, the technology for their construction improves. This is due to the fact that the requirements for thermal insulation standards are constantly increasing. The harsh climate of Canada, Norway, Finland and other Scandinavian countries, where this technology was originally used, contributes to the movement of construction thought forward. An innovative method was the DOK technology - a double volumetric frame. For Russia, a significant part of which has climatic conditions similar to those of the northern states, this technology is relatively new, but has its own percentage of popularity. Single-frame country houses, as practice has shown, did not live up to expectations, so our builders are turning their attention to double-frame technology. Double frames are used for the construction of housing suitable for year-round living in northern latitudes with a harsh climate. This technology can significantly reduce heating costs due to the increased thermal resistance of walls. In areas with a warm climate, a double frame is used in the construction of houses in urban suburbs or cottage villages in order to provide reliable protection of the room from external noise, as well as if the house is equipped with a home theater. Double volumetric house frame Two insulated wooden frames, rigidly connected to each other, are the basis of this type of frame. The load-bearing frame racks are placed in a checkerboard pattern at a distance that allows insulation of the required thickness to be placed in the resulting gap. The gap filled with polyurethane foam, mineral wool or polystyrene foam does not have cold bridges, and this indicates a significant increase in the energy efficiency of the house. The double frame has a number of advantages and disadvantages, which we will discuss below. Advantages of a double volume frame Houses built using double-frame technology have a service life two or even three times longer than houses with a single frame. This effect is achieved precisely by the absence of cold bridges. In such conditions, the possibility of mold appearing, damaging load-bearing structures, is significantly reduced, since condensation does not accumulate in the walls. A “healthy” tree is the key to the longevity of a structure. The double frame increases the load-bearing capacity. Internal partitions need not be erected on an area reaching 25 m2. Options for room layouts can be very diverse, and in this case there is room for the imagination of planners and designers to run wild. In addition, the increased rigidity of the frame completely eliminates the phenomenon of vibration of the building. An increased level of sound insulation is achieved due to the fact that the insulation has the ability to dissipate sound waves. This indicator is of no small importance, especially if the house is located in close proximity to the road. There is no need to use additional insulation in a double-frame house, and the outside of the house can be sheathed immediately after construction is completed. These facts make it possible to slightly reduce the cost of construction. The requirements for the quality of building materials for a frame house are always high. However, there are situations when the frame has to be assembled from a “not quite high-quality” board. Double framing helps solve the problem: uneven boards can be positioned so that they are inside the wall. Covered with plasterboard, they do not spoil the appearance of the interior. Disadvantages of a double volume frame To build a house with such a complex frame structure, a large amount of lumber is needed. The frame is double - the costs are also double. The disadvantages sometimes include the fact that the complexity of such a frame requires the involvement of the highest class specialists, both at the design stage and for the construction itself. Conclusions (Opinions) There are different opinions among builders regarding the advisability of building houses using double volumetric frame (DFC) technology. Considering the fairly high cost, it makes sense to evaluate the value for money. Some believe that as a result of using this technology, the customer receives a structure that is reliable, durable and aesthetically pleasing. Interior and exterior decoration can have many options, which adds advantages when choosing frame houses of this type. Builders have a different opinion, believing that the savings obtained during the operation of the house can cover the amount of the initial investment only after 15-25 years. Theoretically, an ordinary single frame fully meets the requirements for the thermal insulation qualities of Canadian houses, and can be used without fear or doubt even in the polar regions of Russia. In practice, it turns out that our people are more thermophilic. Another aspect considered by these specialists is the effectiveness of using additional lathing to give the frame increased rigidity and strength, and the walls themselves - improved thermal insulation. According to their calculations, the gain is only 5 percent, but the costs increase to 15 percent. Thus, it turns out that investing in the construction of a double volumetric frame is not justified. Of course, every opinion has the right to life. The developer should be aware of them, but make a decision that represents the “golden mean”. Perhaps this will be a universal option, proposed by experts who believe that a double frame should be used in cases where it is planned to insulate a house with insulation whose thickness exceeds 200 millimeters. This layer of thermal insulation has quite a lot of weight and creates an increased load on the frame - a double frame will help minimize it. Conclusion Interest in frame houses in Russia has been increasing over the years. Many technologies for their construction make it possible to make the only right decision, as a result of which your dream will come true! In the village of Karinskoye, we offer the construction of country houses using DOK technology, recognized as the best technology in the world. DOC homes take care of you and your loved ones: DOK is the only technology that eliminates cold bridges in the walls of a house. This makes the house not only durable, but also environmentally safe for the health of people and pets. Cottages built using DOK technology are record holders for energy efficiency among all the country houses, and according to strength– superior to other types of frame houses. Operating and heating such a house costs much cheaper. It is not for nothing that Western companies have switched from the construction of a conventional frame to a double volumetric frame. Only the highest quality materials are used, and the price remains the same as a regular single frame. Back in the middle of the 20th century, many Western companies began to build using DOK technology. This happened in the homeland of frame housing construction - Canada and the USA. In English-language literature they are called double stud wall framing, double stud wall construction, staggered stud wall, etc. The construction of the DOK began for two purposes. In Canada and the northern United States - to create energy-efficient housing suitable for year-round living in harsh climatic conditions. The double wall design made it possible to eliminate cold bridges, significantly increasing the durability and energy efficiency of the house while simultaneously increasing strength. In the southern United States, DOC technology has become widespread due to its unique soundproofing properties - which is especially important in the noisy suburbs of California and Texas. This is the so-called double stud wall soundproofing. Gradually, other advantages of the DOK technology were discovered - colossal savings on heating, the ability to withstand enormous static and dynamic loads, and special durability. Our company has completely mastered this technology in just a few years. For each house we develop an individual working design with unique technological features and components. Working documentation is the property of the company. Only the NANOSPHERE Group of Companies has the right to build houses using DOK technology in Russia. In America, houses built using DOC technology are called Ferrari House. © NANOSPHERE. All materials and design of this site are subject to copyright. Copying, distribution or any other use of information and objects without the prior consent of the copyright holder is prohibited. The site is not a public offer.
Is it worth making the walls (floors) even thicker and the problems that arise from this?
Thickness of enclosing structures: which one to choose?
Advantages and disadvantages of volumetric frame technologies
Double cross frame
Double volumetric frame (DOC)
3-D frame
As a result, with such an arrangement, heat loss through a wooden structure is minimized so much that it approaches the rate of heat loss through the insulating material. In practice, this means an even higher thermal efficiency of the 3-D system compared to double cross or double volume frames.
Double frame and Larsen struts
Advantages of double frames:
Disadvantages of double frames:
Is single frame a thing of the past?
Frame houses using DOK technology
A new level of frame construction
Features of the method, price
How DOK construction works
Finishing a frame house for a summer residence, video
Complete set of the house using DOK technology:
DOK in the West and in Russia
