With what step should the racks be placed when designing the frame of a house or outbuilding? What to be guided by when choosing the pitch of the racks in frame house? The size of OSB sheets, plywood or the width of the insulation? How to take into account the deformation gap between the sheets of the outer skin, in the step of the wooden frame racks?

These are the first questions that appear for anyone who decides to design a frame house or any other building based on a wooden frame with their own hands. In literature and textbooks, the pitch of the racks is often 600 mm. in the centers of the racks or in 575 mm. between the racks, without particularly explaining what caused these recommendations. And the lack of clear explanations makes many think and start looking for “their own way”…

The choice of the pitch of the racks during the construction of the frame must be approached comprehensively: i.e. take into account the format of OSB sheets or plywood for the outer cladding of the frame, what will be used to insulate the walls, how and with what the interior of the house will be finished. This approach will make it possible to optimally use materials, minimize waste, and find new opportunities to save effort, time, materials, and therefore money. So when choosing the step of the racks, we first advise you to think about how the “pie” of the wall in your frame house will look like.

What does mean? For example, if the frame wall looks like this () siding, hydro-wind protection, osb, eco-wool insulation, kraft paper, drywall. It makes sense to calculate the pitch of the racks for the dimensions of OSB or drywall, since the pitch of the racks is not of fundamental importance for insulation with eco-wool.

What to choose? Format of drywall sheets or OSB boards? In this case, it is more reasonable to calculate the pitch of the frame racks for the format of drywall sheets, which is 600 mm, and cut the OSB outer sheathing sheets, taking into account the deformation gap.

In another option () slabs are used to insulate walls basalt insulation"Rockwool", 600 mm wide. with a deformation strip of 50 mm. For external wall cladding, OSB sheets 2500 x 1250 x 12 mm, and interior decoration produce lining. Here, the determining influence on the pitch of the racks in the frame of the house is in the format of OSB and stone wool slabs. Since we have basalt wool slabs with a deformation strip of 50 mm, the size between the posts can vary from 595 to 560 mm. The length of the lining also does not affect the pitch of the racks in the frame. Of the determining factors, only the size of the OSB sheets remains.

Suppose our building does not have complex corners, balconies and bay windows, which allows the formation of an expansion joint between the OSB sheets directly on the wall, simply by setting the circular saw blade to the thickness of the OSB plate and “driving” all the joints of the sheets, before installation truss system and roofs. The size of OSB sheets is 2500 x 1250 mm. Based on this, we get the step of the racks in the frame 625 mm, and the distance between the racks will be 575 mm. This is enough to install basalt wool slabs solely due to the deformation strip provided on them, without additional trimming of the slabs.

But if the frame of the house or the household block is insulated with foam plates, then it is better to calculate the step of the racks according to the size of the plates. Otherwise, a lot of waste is generated. The calculation of the pitch of the wall frame racks for foam insulation has its own characteristics. Fresh foam sheets lose about 1 percent in size for about six months, then this process stops, that is, a sheet of 100 x 200 cm will subsequently dry out to 99 x 199 cm.

If the sheets are cut with a saw with a fine tooth, then another 3-4 mm must be subtracted. Sawing a sheet that has lain for six months, we will get two strips with a width of about 492 - 494 mm. There are two ways to fix the foam between the racks of the wall frame:

Option one (), the opening between the posts is reduced by 7 - 10 mm, i.e., the posts are placed in increments of 530 - 535 mm. so that the foam sheets during installation enter between the racks, slightly squeezing, leaving no gaps, which later can become cold bridges. For such installation of foam requires accuracy and experience.

In the second option (), the racks are installed in increments of 560 mm. so that on all sides the opening is 6 - 10 mm larger than the size of the foam boards. After that, the slots on the sides, top and bottom are filled mounting foam. The gap is 6 - 10mm. optimal, in gaps less than 5 mm. the spout of the mounting gun is not included, and the gaps are more than 10 mm. increase the consumption of mounting foam.

But whatever you choose for insulation and wall decoration, when using 50 x 150 mm boards as frame racks. the pitch of the racks should not exceed 650 mm, and when using a board 50 x 100 mm. the maximum distance between the posts is 400 mm.

In general, as you can see the universal answer to the question, what step of the racks to choose during construction frame house, No. You need to choose it comprehensively, taking into account both what the house will be insulated with and what it will be finished with. Otherwise, you may find that all materials will have to be cut and cut, increasing waste, labor costs, and the construction budget.

The strength of a frame house is determined by its design. The weight of the walls, ceilings and roofs are supported by the supporting frame of the frame house. For the strength of the frame house, it is important to choose the right thickness of the bearing racks, as well as the distance between the racks. There are rules. Today we will discuss how to calculate the distance between the posts in a frame house, the so-called pitch of the racks in a frame house.

Rack pitch in a frame house

The distance of the racks in a frame house is determined by their strength and future load. The stronger the racks of the frame, the greater the gaps between them. In addition, the size of the frame house racks is affected by the size of the finishing materials. Why should the distance between the supports take into account the dimensions of the finishing panels?

Step in the frame wall.

Let's take an example. For ease of installation of OSB sheets, they try to choose the step between the racks, taking into account their sizes. OSB dimensions are 2500x1250 mm. This means that when the distance between the posts is a multiple of 1250 mm (or a multiple of 2500 mm), the flow finishing material on trimming will be quite minimal. The edges of the OSB sheet will be attached to the rack. At a distance greater than 1250, part of the OSB sheet will be cut off during installation.

They also try to take into account the dimensions of the future insulation. For example, if the frame house is insulated from the inside with Rockwool mineral wool mats, then their dimensions are 1200x600 mm with a deformation strip of 50 mm. Then the distance between the posts for insulation should be 550 mm. Which does not correspond to 1250 mm OSB. In this case, when choosing the pitch of the supports, the dimensions of the insulation are not taken into account, and additional strips are provided for its installation in the frame.

On a note

It is also necessary to take into account that in the places where doors and windows are installed, the distance between the racks in the frame house can be more or less. The distance should correspond to the width of the future window or doorway.

The choice of fasteners will be determined by the frame material. The vertical racks of a wooden frame house are attached to the lower and upper trim using metal corners and nails. And metal vertical supports are twisted with bolts or welded by arc welding.

So, we figured out the features of the choice of step and the selection of fasteners. Now let's turn to the calculations and calculate the weight of the future frame, the thickness of the supports and the distance between them.

How much does the frame weigh

The frame of the house is the supporting system. Its strength must withstand the pressure of walls, ceilings and roofs. Therefore, to calculate the racks of a frame house, it is necessary to determine the weight of the future structure. How to do it?

The weight of the walls of the frame.

There are several methods for determining the weight of a future structure. Let's take two:

1. Determining the weight of a building using an online calculator. In this version, the values ​​​​of the width and length of the walls of the building, its height, the number of load-bearing partitions, as well as the material of the walls, their thickness are entered into the calculator and the finished result is obtained - the approximate weight of the future structure.
2. Calculations on construction tables. This is a more complex and painstaking work, during which you can get a more accurate result. According to the construction tables, an approximate specific gravity 1 cu. m, as well as the linear weight of each meter of floors, roofing sheets. The data obtained are multiplied by the area of ​​\u200b\u200bthe walls of the house or roof, summed up and added up to the total weight of the frame house.

The weight of the future structure obtained in the calculations is multiplied by a factor of 1.1. It takes into account the additional weight of plumbing fixtures, furniture, which will be located in the building. As a result, we get the weight that the frame of the house must withstand for many years of operation.

According to the online calculator, we get that 8x8 m with a metal profile roof and wooden lags, in the climatic zone with winter temperatures of -10 will be about 10.5 tons. Multiplying by the coefficient, we get 11.55 tons, which, for convenience of calculations, are rounded up to 12 tons of building weight. So what to do next?

Frame house racks

Next - let's turn to the strength of wooden racks, and find out how much weight each support rack can withstand. Traditionally for wooden frames one-story buildings use the corner posts of a frame house with a section of at least 100x50 mm, for two-story houses - 150x50 mm. Using the reference tables, we determine the bearing capacity of the frame rack.

Distance between bases.

On a note

The calculation of the bearing capacity by the formulas is quite complicated and is associated with the knowledge of the resistance of materials.

According to the directory physical properties wood, the compressive strength of wood is 30 - 50 MPa (depending on the type of wood). This means that each cm section can withstand 30-50 kg of weight. Racks of the walls of a frame house 100x50 mm are guaranteed to withstand 300 kg.

Given the total weight of the house, determined earlier, you can calculate the minimum number of support posts. To do this, we divide 12,000 kg by 300 kg, as a result of which we get that the installation of racks will require 40 boards with a section of 100x50 mm.

Distance between supports

The distance of the racks in a frame house is determined by the load or weight of the house, the number of supports. Using the data obtained, we determine the required distance between the racks of the frame. To do this, we calculate the total perimeter of the wall. In a house of 8x8 m, it will be 32 m. After that, we divide the resulting 32 m by the number of racks of 40 pieces. We get a distance of 0.8 m or 800 mm.

In the construction literature there are general recommendations on how to properly mount the racks of a frame house. They say that if it is impossible to perform construction calculations, the step between is selected in the amount of 500 to 700 mm. And one more thing: it is accepted that the step of the racks of a frame house should not exceed 1 m.

The most capacious stage of frame construction in the technology of frame housing construction is the installation of vertical racks. It takes most of the time to build frame walls. It is necessary to carry out the installation of racks with particular care, since these are the main elements that ensure the structural stability of the "skeleton" of the building. In addition, the installation of racks determines the quality of laying the insulation and, accordingly, the quality of the entire insulation of the house.

1. Stages of frame construction

Recall the main stages of frame construction in frame technology:

1. Bottom trim of the foundation
2. Basement and subfloor installation
3. Rack installation
4. Upper trim of racks
5. Ceiling installation.

By the time of the stages, the installation of racks is the longest operation, since the number of elements here is the largest. Each rack must be connected to the base and additionally strengthened so that during the installation process their verticality is maintained.

2. Preparing the uprights - board selection

There are several basic techniques for building a frame using frame technology. The first way is to assemble the frame frame on the floor, lift it up and install it vertically around the entire perimeter.

The second way is to install each rack vertically separately.

Fundamentally, both methods differ in that the racks are fastened in the first case to the upper and lower beams of the frame, and in the second - directly to the foundation strapping. However, the attachment methods themselves are the same, so let's take a closer look at the second case, as the most revealing.

Racks perform a crucial function - ensuring the structural strength of the frame, taking on significant (up to 3-5 tons) loads from the roof and roof. The material for them, respectively, chooses durable and high-quality.

The biggest loads fall on the corner posts, so a massive beam is taken for them - usually 100x100 mm. The side posts, located along the line of the wall, carry a smaller load individually, and for them, as a rule, a bar with a section of 40x100 mm is sufficient. You can also use bars of large sections, but it will generally cost more. If necessary, you can sew racks from two boards of a smaller section, 25-30 mm thick.

3. Installation of corner posts

First, install the side racks. In the simplest case, they are attached to the base using reinforced metal corners. The corners themselves are screwed to the boards with screws or nails. It is advisable to use galvanized corners - they are less susceptible to corrosion. Corner posts must be carefully checked for verticality with a plumb line. For their further stability in a vertical position, it is desirable to install temporary braces until the frame is finally fastened.

There is another way to fasten the side racks - with a wooden dowel. Nagel is a small bar round section. It is hammered in when assembling the corner of the lower harness - into pre-drilled holes - so that the dowel protrudes 8-10 cm above the strapping plane. This additionally fastens the strapping bars and serves as an element connecting the strapping to the rack.

A hole is also drilled in the rack beam for the diameter of the dowel and a depth of 8-10 mm more than the length of the dowel release. Then the rack is put on the dowel and also fixed with braces. This method is quite laborious, but has several advantages:

• No metal fasteners subject to corrosion
• A more reliable connection than a threaded one, weakening over time due to drying out of the wood

The connection of homogeneous materials contributes to greater plasticity under lateral loads on the racks.

4. Fastening the side racks to the bottom trim

After installing the corner posts, proceed to the installation of the side ones. Here the most significant is the choice of the installation step of the racks. The calculation of the distance between the racks takes into account:

• Structural loads on the entire wall
• The method of laying insulation
• Locations for window and door openings.

It is advisable to prepare the required number of racks in advance, and saw them off according to a template so that errors in the size of any of the racks do not affect others.

The side racks are attached to the lower base in several ways:

• With the help of metal braces
• Inserts in cut grooves
• Steel angle mounting.

Metal jibs are installed a little differently than wooden jibs, since the wooden jibs are subsequently removed, while the metal ones remain forever. They are mounted flush with the side surface of the racks and the bottom trim, that is, first, grooves corresponding to the thickness of the metal plate are selected in the rack and trim. Fastening of the corners is carried out on self-tapping screws or nails.

The second method is as follows - in the lower support beam, grooves are selected according to the sectional shape of the rack, and the rack is inserted into them.

It is very important to take into account that when fastening with corners, the height of the vertical rack is equal to the height of the floor. And when fastening by cutting, the height of the rack should be more than exactly 2 cutting depths.

Fastening with a metal corner is carried out similarly to the described method for installing side racks.

The step of the racks is planned depending on

• Dimensions of the inner and outer skin of the frame cell
• Dimensions of insulation boards

So, most of the OSB sheets used for sheathing are produced with a width of 1200 mm, and the step of the racks is chosen at 600 mm. The edges of the sheathing sheets must necessarily fall on the rack at the docking points, otherwise the racks must be installed additionally.

Insulation slabs, such as basalt wool, are also produced with sizes suitable for a typical rack pitch. If rolled mineral wool or other types of insulation are used, then for them the distance between the racks is unimportant. The insulation in this case is cut out under the existing step of the racks.

In order to prevent the racks from tilting during operation, it is advisable to set temporary braces for each - or simultaneously for several racks.

After installing and tying all the racks, it is imperative to install jibs - these are elements from the board that serve to fasten the frame and give it structural strength. The purpose of the jibs is to counteract lateral loads on the house - these are mainly wind loads. The jibs are cut at an angle to the vertical posts, flush with the outer or inner plane of the wall. We talked about this in more detail in the corresponding article of our site.

5. Conclusion

Installing racks of a frame house is the longest operation of erecting the "skeleton" of a structure. It can be significantly accelerated if the frame frames are assembled in advance, so that all that remains is to raise them vertically along the perimeter.

The company "K-DOM" is currently mastering the assembly of frame frames at its own production facilities. The dimensions of the frame frames correspond to the design of the house and are negotiated with the customer. Such work will save the builder time for the builders to go directly to the place where the house is being built.

Have you ever come across the fact that in discussions on the forums the topic of the “right” or “wrong” frame house pops up? Often people are poked with their noses at the fact that the frame is wrong, but they really find it difficult to explain why it is wrong and how it should be. In this article I will try to explain what is usually hidden behind the concept of a “correct” frame, which is the basis of a frame house, just like a human skeleton. In the future, I hope, we will consider other aspects.

Surely you know that the foundation is the foundation of the house. This is true, but the frame house has another basis - no less important than the foundation. This is the frame itself.

Which frame house is “correct”?

I'll start with the main one. Why is it so difficult to talk about the right frame house? because the only correct correct frame house does not exist. What a surprise, isn't it? 🙂

You will ask why? Yes, very simple. A frame house is a large constructor with many solutions. And there are many decisions that can be called correct. There are even more decisions - “semi-correct”, but there are a legion of “wrong” ones.

Nevertheless, among the variety of solutions, one can single out those that are usually meant when speaking of “correctness”. This is a frame of the American and, more rarely, Scandinavian type.

Why are they considered examples of “correctness”? Everything is very simple. The vast majority of private homes for permanent residence in America, and a very significant percentage in Scandinavia, are built using frame technology. This technology has been used there for more than a dozen and perhaps even a hundred years. During this time, all possible cones were filled, all possible options were sorted out and a certain universal scheme was found that says: do this and with a probability of 99.9% you will be fine. Moreover, this scheme is the optimal solution for several characteristics at once:

1. Structural reliability of solutions.
2. Optimal labor costs during construction.
3. Optimal cost of materials.
4. Good thermal performance.

Why step on your own rake if you can use the experience of people who have already stepped on this rake? Why reinvent the wheel if it has already been invented?

Remember. Whenever we are talking about the “correct” frame or about the “correct” nodes of a frame house, then, as a rule, this means standard solutions and nodes used in America and Scandinavia. And the frame itself satisfies all the above criteria.

What frameworks can be called “semi-regular”? Basically, these are those that differ from the typical Scandinavian-American solutions, but, nevertheless, also satisfy at least two criteria - reliable design and good solutions in terms of heat engineering.

Well, I would classify all the rest as “wrong”. Moreover, their “incorrectness” is often conditional. It is not at all a fact that the “wrong” frame will necessarily fall apart. Such a scenario is actually extremely rare, although it does occur. Basically, the “wrongness” lies in some controversial and not the best decisions. As a result, it becomes difficult where it can be done easier. More material is used where less is possible. A colder or more inconvenient design for subsequent work is made than it could be.

The main drawback of the “wrong” frames is that they do not give absolutely any gains compared to the “correct” or “semi-correct” ones - neither in reliability, nor in cost, nor in labor costs ... nothing at all.

Or these advantages are far-fetched and generally questionable. In extreme cases (and there are some), improper framing can be dangerous and result in a home needing a major overhaul in just a few years.

Now let's look at the issue in more detail.

Key Features of the American Frame

The American frame is practically a standard. It is simple, strong, functional and reliable as an iron saw. It is easy to assemble, it has a large margin of safety.

Americans are tight-fisted guys, and if they manage to save a couple of thousand dollars on a construction site, they will definitely do it. At the same time, they will not be able to stoop to outright hack-work, since there is strict control in the construction industry, insurance companies will refuse to pay out in case of problems, and the customers of would-be builders will quickly sue and rip negligent contractors like sticky.

Therefore, the American frame can be called the standard in terms of the ratio: price, reliability, result.

American frame is simple and reliable

Let's take a closer look at the main points that distinguish the American wireframe scheme:

Typical nodes of a frame house

Beam in racks and harnesses is almost never used, unless it is due to some specific conditions. Therefore, the first thing that distinguishes the “correct” frame house is the use of dry lumber and the absence of timber in the walls. By this criterion alone, you can discard 80% of Russian companies and teams operating in the frame market.

Moments that distinguish the American frame:

1. Corners - There are several different ways to implement corners, but nowhere do you see a beam as a corner post.
2. Double or triple racks in the area of ​​window and door openings.
3. The amplifier above the openings is a board mounted on an edge. The so-called "header" (from the English header).
4. Double top strapping from the board, no timber.
5. The overlap of the lower and upper rows of strapping at key points - corners, different fragments of walls, junctions of internal partitions to external walls.

Ukosina I specifically did not note as a distinctive moment. Since in the American style, in the presence of sheathing with OSB3 boards (OSB) on the frame, there is no need for jibs. The plate can be considered as an infinite number of jibs.

Let's talk in more detail about the key features of the correct frame in the American version.

Correct corners of the frame house

In fact, on the Internet, even in the American segment, you can find about a dozen schemes. But most of them are outdated and rarely used, especially in cold regions. I will highlight three main angle patterns. Although realistically, only the first two are the main ones.

Knots of the corners of the frame house

1. Option 1 - the so-called "California" corner. The most common option. Why "California" - I have no idea :). From the inside, another board or strip of OSB is nailed to the extreme rack of one of the walls. As a result, a shelf is formed on the inside of the corner, which later serves as a support for the interior decoration or any inner layers of the wall.
2. Option 2 - closed corner. Also one of the most popular. The bottom line is an additional rack in order to make a shelf on the inner corner. Of the advantages: the quality of the insulation of the corner is better than in option 1. Among the disadvantages: such a corner can only be insulated from the outside, that is, this must be done before sheathing the frame with something from the outside (plates, membrane, etc.)
3. Option 3 - "Scandinavian" warm corner. A very rare variant, not used in America. I saw it in Scandinavian frames, but not often. Why did I bring him then? Because, in my opinion, this is the warmest version of the corner. And I'm thinking about starting to apply it to our facilities. But before using it, you need to think, since it is structurally inferior to the first two and will not work everywhere.

What is the peculiarity of all these three options and why is a beam a bad option for a corner?

Angle from a bar, the most losing option

If you notice - in all three options from the boards, the corner can be insulated. Somewhere more, somewhere less. In the case of a beam in the corner, we immediately have 2 drawbacks: firstly, from the point of view of heat engineering, such a corner will be the coldest. Secondly, if there is a beam in the corner, then there are no “shelves” from the inside to attach the interior trim to it.

Of course, the last question can be solved. But remember what I said about “wrong” wireframes? Why make it difficult when you can make it easier? Why make a beam, creating a bridge of cold and thinking how to attach the finish to it later, if you can make a warm corner from the boards? Despite the fact that this will not affect the amount of material or the complexity of the work.

Openings and top trim are the most significant difference between the American frame scheme and the Scandinavian one, but more on that later. So, when they talk about the correct openings in the frame, they usually talk about the following scheme (window and door openings are made according to the same principle).

Correct openings in a frame house

The first thing (1) that people usually pay attention to when talking about “wrong” openings is the double and even triple posts on the sides of the opening. It is often believed that this is necessary for some kind of strengthening of the opening to install a window or door. Actually this is not true. A window or door will be fine on single racks. Why then do we need cohesive boards?

Everything is elementary. Remember, I said that the American frame is as simple and reliable as an iron saw? Pay attention to figure 2. And you will understand that cohesive racks are needed solely to support the elements lying on them. So that the edges of these elements do not hang on nails. Simple, reliable and versatile.

In Figure 3 - one of the simplified varieties, when the bottom trim of the window crashes into a broken rack. But at the same time, both window trims still have supports at the edges.

Therefore, it is impossible to speak formally about the fact that if the racks are not doubled, then this is “wrong”. They can also be single, as in the Scandinavian frame. Rather, it is a mistake when the posts along the edges of the openings are cohesive, but do not bear the load from the elements based on them. In this case, they are simply meaningless.

In this case, the horizontal elements are hanging on the fasteners, so there is no point in doubling or tripling the racks on the sides.

Now let's talk about an element that is already more critical and the absence of which can be considered as an "irregularity" of the opening. This is the “header” above the opening (header).

Window header

This is the really important element. As a rule, some kind of load will come from above to the window or doorway - the logs of the second floor, the rafter system. And the wall itself is weakened by deflection in the area of ​​the opening. Therefore, local reinforcements are made in the openings. American style is headers. In fact, this is a board mounted on an edge above the opening. Here it is already important that the edges of the header either rest on the posts (if the classic American scheme with cohesive posts of openings is used), or be cut into the extreme posts, if they are single. Moreover, the cross section of the header directly depends on the loads and dimensions of the opening. The larger the opening and the stronger the load on it, the more powerful the header. It can also be double, triple, increased in height, etc. Again, it depends on the load. But, as a rule, for openings up to 1.5 m wide, a header from a 45x195 board is enough.

Is the absence of a header a sign that the framework is “wrong”? Yes and no. If you act according to the American principle of “simple and reliable”, then the header must be present at every opening. Do this and be sure of the result.

But in fact, you need to dance from the load falling on the opening from above. For example, a narrow window in a one-story house and rafters in this section of the wall are located along the edges of the opening - the load from above on the opening is minimal and you can do without a header.

Therefore, the issue of the header should be treated as follows. If it exists, great. If it is not there, then the builders (contractor) must clearly explain why, in their opinion, it is not needed here, and it will depend, first of all, on the load falling on the opening zone from above.

Double top harness

Double plank top piping, also a distinctive feature of the American frame

Double top harness

The double strapping again gives reinforcement along the top of the wall for deflection from the load from above - the load from the ceiling, rafters, etc. In addition, pay attention to the overlaps of the second row of strapping.

1. Overlap in the corner - we tie together two perpendicular walls.
2. Overlap in the center - we tie together 2 sections of one wall.
3. Overlap on the partition - we tie together the partition with the outer wall.

Thus, the double strapping also performs the second task - ensuring the integrity of the entire wall structure.

In the domestic version, you can often find the upper trim of the timber. And this, again, is not the best solution. Firstly, the beam is thicker than the double strapping. Yes, it may be better for deflection, but it’s not a fact that it is necessary, but the cold bridge at the top of the wall will be more significant. Well, it’s more difficult to implement this overlap to ensure the integrity of the entire structure. Therefore, we return again to the fact that why is it difficult to do, if you can make it easier and more reliable?

Proper jib in a frame house

Another cornerstone. Surely you have come across the phrase “the jibs are made incorrectly”. Let's talk about it. First, what is a slug? This is a diagonal element in the wall, which provides spatial shear rigidity in the lateral plane. Because thanks to the jib, a system of triangular structures appears, and the triangle is the most stable geometric figure.

So, when they talk about the correct jib, then usually we are talking about this option:

Correct jib

Why is such a jib called “correct” and what should I pay attention to?

1. Such a jib is installed with an angle of 45 to 60 degrees - this is the most stable triangle. Of course, the angle may be different, but it is this range that is best.
2. The jib cuts into the upper and lower trim, and does not just rest against the rack - this is quite an important point, so we tie the structure together.
3. The jib crashes into every post in its path.
4. For each node - adjoining to the harness or rack, there must be at least two fastening points. Since one point will give a “hinge” with a certain degree of freedom.
5. The jib cuts into the rib - this way it works better in the structure and interferes less with insulation.

And here is an example of the most “wrong” jib. But nevertheless, it occurs all the time.

It's just a board stuck into the first opening of the frame. What is so “wrong” about it, because formally it is also a triangle?

1. First - a very small angle of inclination.
2. Secondly, in such a plane, the jib board works the worst.
3. Thirdly, it is difficult to fix such a jib to the wall.
4. Fourthly, pay attention to the fact that extremely inconvenient cavities for insulation are formed at the points of junction with the frame. Even if the jib is carefully cut and there is no gap at the end, there is no escape from an acute angle, and it is not an easy task to insulate such an angle with high quality, so most likely it will be done somehow.

Another example, also common. This is a jib cut into the posts, but not cut into the harness.

The jib is not embedded in the harness

This option is already much better than the previous one, but, nevertheless, such a jib will work worse than embedded in the strapping, and after all, the work is 5 minutes more. And if, moreover, it is fixed to each rack with only one nail, then the effect of it will also be minimized.

We won’t even consider options for all sorts of small inferior “braces and braces” that do not reach from the top trim to the bottom.

Formally, even the most crooked jib makes at least some contribution. But once again: why do it your way when a good solution already exists?

On this we will finish with the American frame and move on to the Scandinavian one.

Correct scandinavian frame

Unlike America, where the frames are practically standardized and there are very few differences, there are more variations in Scandinavia. Here you can find both the classic American frame and hybrid versions. The Scandinavian frame, in fact, is the development and modernization of the American one. However, basically, when they talk about the Scandinavian frame, we are talking about such a design.

Typical Scandinavian house set

scandinavian frame

Corners, jibs - everything is like the Americans. What to pay attention to?

1. Single strapping on the top of the wall.
2. Power crossbar embedded in racks throughout the wall.
3. Single racks on window and door openings.

In fact, the main difference is this very “Scandinavian” crossbar - it replaces both American headers and double strapping, being a powerful power element.

What, in my opinion, is the advantage of the Scandinavian frame over the American one? The fact that it has a much greater emphasis on minimizing all kinds of cold bridges, which are almost all cohesive boards (double strapping, opening racks). Indeed, between each cohesive boards, a gap can potentially form over time, which you may never know about. Well, it's one thing when the cold bridge has the width of one board and another question - when there are already two or three of them.

Of course, you should not get hung up on cold bridges. You can’t get away from them anyway, and in fact, their importance is often exaggerated. But, nevertheless, they exist, and if it is possible to minimize them relatively painlessly, why not do it?

The Scandinavians in general, unlike the Americans, are very confused about energy saving. The colder, northern climate and expensive energy sources also have an effect. But in terms of climate, Scandinavia is much closer to us (I'm talking primarily about the Northwestern region) than most American states.

The disadvantage of the Scandinavian frame is its slightly greater complexity, at least in the fact that in all racks you need to make cuts under the crossbar. And the fact that, unlike the American one, it still requires some kind of mental effort. For example: on large openings, double posts to support horizontal elements, and additional crossbars and headers may be required. And somewhere, for example, on the gable walls of one-story buildings, where there is no load from the log or roof, the crossbar may not even be required.

In general, the Scandinavian frame has certain advantages, but requires a little more effort and intelligence than the American one. If the American frame can be assembled with completely disabled brains, then in the Scandinavian one it is better to turn them on, at least on the minimum mode.

"Semi-correct" frames

Let me remind you that by “semi-correct” I mean precisely those that have every right to exist, but differ from typical Scandinavian-American solutions. Therefore, calling them “semi-correct” should be cautious.

I will give a few examples.

An example of how you can "override"

The first example is from our own practice. This house was built by us, but according to the project provided by the customer. We even wanted to redo the project completely, but we were limited by the deadlines, since we had to go to the site; in addition, the customer paid a tangible amount for the project and formally there are no structural violations, but he reconciled with the voiced shortcomings of the current solution.

Why, then, did I classify this frame as “semi-correct”? Pay attention to the fact that here there are Scandinavian crossbars, and American headers, and double strapping not only along the top, but also along the bottom of the walls. In short, here is the American scheme, and the Scandinavian one, and another 30% of the stock in Russian is thrown on top, just in case. Well, the prefabricated rack of 6 (!!!) boards under the glued beam of the ridge speaks for itself. Indeed, in this place the only insulation is isoplats from the outside, and cross-insulation from the inside. And if there was a purely American scheme, then there would simply be no insulation in this section of the wall, a bare piece of wood from the outside to the inside.

I call this frame “semi-correct” because from the point of view of constructive reliability, there are no complaints about it. There is a multiple margin of safety "in case of an atomic war." But the abundance of cold bridges, and a huge overrun of material for the frame, and high labor costs, which also affects the price.

This house could be made with a smaller, but sufficient margin of safety, but at the same time reduce the amount of lumber by 30 percent and significantly reduce the number of cold bridges, making the house warmer.

Another example is a “double-volume” framework promoted by a Moscow company.

The main difference is actually a double outer wall, with posts spaced apart from each other. So the frame fully satisfies the strength criteria and is very good from the point of view of heat engineering, due to the minimization of cold bridges, but loses in manufacturability. The task of eliminating cold bridges, which, first of all, is solved by such a frame, can be solved by simpler, more reliable and correct methods such as “cross-insulation”.

And, curiously, usually “semi-correct” frames somehow have Scandinavian-American solutions in them. And the differences are rather in an attempt to improve the good. But it often happens that it turns out that “the best is the enemy of the good”.

Such frameworks can safely be called “semi-correct” precisely because there are no gross violations here. There are differences from the typical American-Scandinavian decisions in attempts to improve something or come up with some kind of “trick”. To pay for them or not is the choice of the customer.

"Wrong" frame houses

Now let's talk about the "wrong" frames. The most typical, I would even say, collective, case is presented in the photo below.

The quintessence of "correct" frame housing construction

What can be immediately noted in this photo?

1. Total use of natural moisture material. Moreover, the material is massive, which dries out the most and changes its geometry in the process of shrinkage.
2. The beam in the corners and on the strapping and even on the racks are cold bridges and inconvenience in further work.
3. Lack of headers and reinforcements of openings.
4. Do not understand how the jib is made, poorly fulfilling its role and interfering with insulation.
5. Assembly on corners with black self-tapping screws, the purpose of which is to fasten the plasterboard during finishing (and not use in load-bearing structures).

The photo above shows almost the quintessence of what is commonly called the “wrong” frame or “RSK”. The abbreviation RSK appeared in 2008 at the FH, at the suggestion of one builder who presented a similar product to the world, called the Russian Power Frame. Over time, as people began to figure out what was what, this abbreviation began to be deciphered as Russian Strashen Karkashen. As an apotheosis of meaninglessness with a claim to a unique solution.

What is most curious, if desired, it can also be classified as “semi-correct”: after all, if the self-tapping screws do not rot (black phosphated self-tapping screws are by no means an example of corrosion resistance) and do not burst during the inevitable shrinkage of the beam, this frame is unlikely to fall apart. That is, such a design has the right to life.

What is the main disadvantage of the “wrong” frames? If people know what they're doing, they pretty quickly come to the Canadian-Scandinavian scheme. Fortunately, information is now in bulk. And if they don’t come, then this speaks of one thing: they, by and large, do not care about the result. The classic answer when trying to ask them why it is so is “we have always built it this way, no one complained”. That is, the entire construction is based solely on intuition and ingenuity. Without trying to ask - how is it customary to do this.

What prevented you from making a board instead of a beam? Make reinforcements of openings? Make normal cuts? Collect for nails? That is, do it right? After all, such a frame does not give exactly any advantages! One large set of not the best solutions with a claim to super strength, etc. Moreover, the labor input is the same as that of the “correct” one, the cost is the same, and the material consumption, perhaps even more.

Summarize

As a result: it is customary to call the American-Scandinavian frame scheme “correct”, due to the fact that it has already been repeatedly tested on thousands of houses, proving its viability and the optimal ratio of “labor-intensive-reliability-quality”.

“Semi-correct” and “incorrect” include all other types of frames. In this case, the frame can be quite reliable, but “non-optimal” from the side of the above.

As a rule, if potential contractors cannot justify the use of certain design solutions that differ from the “correct” American-Scandinavian ones, this indicates that they have no idea about these very “correct” decisions and build a house solely on a whim, replacing knowledge with intuition and ingenuity. And this is a very risky path that may come back to haunt the owner of the house in the future.

So. Do you want guaranteed correct, optimal solutions? Pay attention to the classic American or Scandinavian scheme of frame housing construction.

about the author

Hello. My name is Alexey, maybe you met me as Porcupine or Gribnick on the Internet. I am the founder of "Finnish House", a project that has grown from a personal blog into a construction company whose goal is to build a quality and comfortable home for you and your children.

Good afternoon (night, morning - how anyone) everyone!

I read SNiPs here, looked at the requirements for fastening various slab materials, read bourgeois books (special thanks to the author of the selection of links posted on the forum). Then I counted a little and thought about it. Namely:

About the thickness of the rack frame house. SNiP requirement: the distance from the edge of the lumber to the axis of the dowel (nail, screw) 3 - 3.5d. The requirement for fastening Greenboard 3, DSP, OSB is 15 mm from the edge of the sheet (or more). The recommended diameter of self-tapping screws is 3.9 - 4.2 mm. Accordingly, the thickness of the rack on which the junction of plate materials takes place should be at least: 3.9x3x2 + 15x2 = 53.4 mm (if the plate material is installed without a gap between the sheets). If you need a gap between the plate material, then the thickness of the rack should be more ...

About the height of the stand. Based on the strength requirements for wooden structures according to SNiP, with a rack thickness of 50 mm, its maximum height can be 266 mm, with a thickness of 45 mm - 240 mm, with a thickness of 40 mm - 213 mm. At the same time, the maximum load on a rack with a thickness of 50 mm and a width of 150 mm at a height of 266 mm can be no more than 1507 kgf (the calculation is correct for wood with a moisture content of not more than 12%, I did not find how to calculate for other humidity). I was sitting here, calculating the loads on the racks of the first floor of a frame house for myself and a little tense - I got less than 20% margin of safety with a rack pitch of 600 mm along the axes, and I could barely fit into the central load-bearing wall with a pitch of 400 mm (I will today to recalculate the load again - something very heavy house turns out). Maybe, of course, out of an old Russian habit, I try to overdo it, but ...

This is where my questions arose: how do gentlemen of practice attach plate material to racks with a thickness of 50 mm or less, taking into account the fact that manufacturers of plate material require self-tapping screws to be installed strictly at an angle of 90 degrees to the plane of the sheet?

How are the frame racks reinforced, taking into account the requirements for strength and real loads?
Is this same slab material needed in the frame at all? Actually, as far as I understand, wind loads plus unevenly distributed vertical ones affect the displacement of the frame from the vertical? If so, then it seems to me that two or three correctly installed braces in each wall should be enough?

Off-top: I talked here in several Moscow companies that make frame houses ... (a lot of unprintable words) ... transfer of loads through window and door frames, 4-meter spans with 45x145 beams with a step of 600 mm ... to the question on the basis of which design decisions were made - they answer on the basis of SNiP, I ask how they thought - but we don’t think ... When using dry lumber (not the fact that it will be dry), not only the material, but also the work becomes more expensive ...

I had to sit down to design it myself - I really don’t want to sit in the bath on the second floor and end up on the first one ... And the budget, alas, is severely limited ...

About the "pie" of the sexes. I see the following designs for dry rooms:
1. Greenboard 3R - 22 mm
2. Plywood - 21 mm
3. Plywood - 15 mm with sanding joints
4. Cork backing - 2 mm
5. Laminate - 9.5 mm
For wet areas:
1. Greenboard 3R - 22 mm
2. Waterproofing
3. Aquapanel Knauf - 12.5 mm
4. Knauf Boden 15 thin-layer gypsum screed with “warm floor” carbon cables recessed into it - 18 mm
5. Tile adhesive Knauf Flex - 5 mm
6. Ceramic tiles - 10 mm
In both cases, the thickness of the “pie” is 69.5 mm (it is clear that I will lose 0.5 mm and it will be 70).

That’s what I didn’t find ... If I put a multi-span beam and put a wall on top in the places where it is supported, then logically I get a rigid seal in all places where the beam is supported. And how then to consider it for strength and deflection? Where can I see the formulas ... Or consider it as several single-span beams?