Useful Tips

The device of the floor in the frame house: features of installation and diagrams for each floor


An important element after the lag of the floor, walls and rafters in the frame house - black floor. The subfloor in the frame house is the initial floor covering, on which they will then lay the final floor covering: linoleum, laminate, parquet, wooden board or tile. Also, a black floor is necessary for the convenience of builders moving around the house, it is very inconvenient and dangerous to walk along the lags.

What is usually made of a rough floor in a frame house?

Option 1. Classic. Plywood or OSB-3
In a Canadian classic frame house, the floor is made from sheet pile plywood. We often do the same, but sometimes they replace it with a cheaper OSB-3 (OSP-3) board. Also OSP-3 (18-22 mm) can replace with a grooved board 36 mm.
In this case, it must be laid across the log, and it is better to lay it upside down for the first time, and turn it over and put the finishing one in a year (this way you will stain it less. In addition, you still need to shift and pull it in a year to there were no gaps).

There are a number of rules that you must follow when laying plywood as a black floor.

1. Plywood is staggered:

That is, the next row in relation to the previous one is offset by joints at half the size of plywood. This is done to increase the strength of the black floor. By the way, did you notice that in the first photo in this article, plywood is positioned incorrectly and is shifted halfway towards each other?

2. Plywood is placed immediately on top of the lag perpendicular to their direction:

3. The thickness of the plywood used depends on the shal lag.

Step lag 300-450 mm - plywood 16-18 mm (OSP-3 18 mm)
Pitch lag 500-625 mm - plywood 18-21 mm (OSP-3 22 mm)

4. Plywood should be joined at the joints of the lag (on the short side):

5. Joints of plywood on the long side (perpendicular to the lags) should be docked on jumpers (bridges):

Thus, we place jumpers every 1250 mm (or 1220 mm, or 1525 mm - depending on the size of the plywood).

6. Fasteners of plywood for logs.

Fasten plywood to lags and lintels or screws (length 50-60 mm) or with brushed nails (60mm) and glue (glue is applied to avoid creaking), which is applied under the plywood to the logs. At the edge of the plywood sheet, the fastener goes in increments of 15 cm, in the middle of the sheet in increments of 30 cm.

7. The gap between the plywood boards in all directions should be 2-3 mm (see the picture above). To do this, for the time of fastening the plates, insert carnations of the corresponding diameter between them.

More pictures with nodes of the black floor of the frame house:

Option 2. Scandinavian
USP or UVP, described them in a post about the foundation for a frame house.

Option 3. Concrete screed
We put plywood as in the first embodiment, the smallest possible thickness is possible. Then, on plywood or OSP-3, we pour a concrete screed of 3-5 cm for waterproofing from the film. In the screed, you can put pipes of the warm floor, then our subfloor will also be responsible for the heating function in the house. For myself, I looked for a similar option for certain circumstances.

Option 4. Wooden board
A black floor (or even a clean floor) in a frame house can also be a wooden board. Of course, the speed of laying the board is much lower than when laying plywood. Usually on the floor lay either an ordinary board with a width of 40-50 mm, or a grooved board of 25-36 mm. In this case, the walls of the frame are not placed on top of the board, but are laid directly on the logs so that the board can be later shifted (when it is dry).

Pluses of the board on the floor of the frame house:
- environmental friendliness
- cheapness
- boards are easier to carry than plywood (because the board is lighter)

Cons of the board:
- cracks in the floor
- floor creaking (often)
- waste of time (pound longer than plywood)

Choose for yourself what to use for the black floor in a frame house, the main thing is that you choose the option you like!
P.S. I chose plywood for myself and have not regretted it yet. I have a warm floor on the plywood and everything looks and feels solid.

What experience do you have? What are you made of or are you planning to make flooring in your home? Share your experiences in the comments.

Send the material to the mail

The device of the subfloor in the frame house depends on the type of foundation on which it stands. And the type of foundation even of such a light structure depends on the nature of the soil. And here there are no restrictions on materials - it can be concrete floors on the ground, and wooden floors on the logs. But the first option, if used, is only on a slab or strip foundation. Although for the strip foundation, the rough floor on the logs is more common. And taking into account the fact that the frame house is usually placed on a screw or column foundation (if the geological features of the site allow), a rough wooden floor is the most common.

All the enclosing surfaces of the frame house are arranged similarly - thin-skinned sheathing with insulation in the middle

General terms

In principle, there are two types of wooden draft floor on the first floor of a frame house:

load-bearing ventilated structure on a tape or pile (screw) foundation,

lattice structure on a slab or concrete screed.

In the first case, the horizontal level should already be observed at the level of the cap, grillage or strapping, in the second - when pouring the base.

If there is a subfloor in the shallow, shallow foundation in the bearing walls of the base around the perimeter and inside it, ventilation ducts should be laid.

Note. Ventilation should also be left when arranging the pick-up (basement) of the pile foundation.

To protect the tree from rotting in contact with a concrete or metal surface, the places of support of the supporting beams of the floor to the foundation are isolated using a roll of bitumen waterproofing.

A wooden beam must be isolated from contact with concrete

All wooden elements must be treated with antiseptics, the metal fasteners used and the attachment points must have an anti-corrosion coating.

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 true correct frame house does not exist. What a surprise, isn't it? 🙂

You will ask why? Yes, very simple. A frame house is a great designer with many solutions. And there are many solutions that can be called correct. Even more decisions are “semi-correct”, but “wrong” are generally legion.

Nevertheless, among the variety of solutions, we can distinguish those that are usually taken into account when speaking of “correctness”. This is the frame of the American and, 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, were 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 it with a probability of 99.9%, everything will be fine with you. Moreover, this scheme is the optimal solution for several characteristics at once:

  1. Design reliability of solutions.
  2. Optimization of labor costs during construction.
  3. Optimized material costs.
  4. Good thermal performance.

Why step on your own rake if you can take advantage of the experience of people who have already stepped on this rake? Why reinvent the wheel if it is already invented?

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

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

Well, to the “wrong" I would attribute all the others. Moreover, their “incorrectness" is often conditional. It’s 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, “wrongness” lies in some controversial and not the best decisions. As a result, it becomes difficult where it can be made easier. More material is used wherever possible. A design is made colder or inconvenient for subsequent work than it could be.

The main disadvantage of “wrong” frames is that they give absolutely no gains compared to “right” or “semi-correct” ones - neither in reliability, nor in cost, nor in labor costs ... in general, nothing.

Or these advantages are far-fetched and generally doubtful. In extreme cases (and there are such), the wrong frames can be dangerous and will lead to the fact that major repairs of the house will be required in a few years.

Now consider the issue in more detail.

Key Features of the American Frame

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

The Americans are fussy guys, and if they manage to save a couple of thousand dollars at a construction site, they will definitely do it. At the same time, they will not be able to go down to blatant hack, since there is tight control in the construction industry, insurance companies will refuse payments in case of problems, and customers of unfortunate builders will quickly sue and strip off negligent contractors like sticky.

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

The American frame is simple and reliable.

Let's consider in more detail the main points that distinguish exactly the American wireframe scheme:

Typical units of frame house

First, it is worth noting that the “right” frame houses are made without the use of timber and only from dry lumber. That is, all racks, harnesses, etc. made only of dry planed boards. Why? Read the article about the choice of lumber for a frame house.

A bar in racks and harnesses is practically never used, unless this 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. According to this criterion alone, you can discard 80% of Russian companies and teams working in the frame market.

Moments that distinguish the American frame:

  1. Corners - there are several different schemes for the implementation of angles, but nowhere you will not see the beam as corner posts.
  2. Double or built racks in the area of ​​window and doorways.
  3. Amplifier over openings - a board mounted on an edge. The so-called “header" (from the English header).
  4. The double top binding from a board, no bar.
  5. The overlap of the lower and upper row of strapping at key points - angles, different fragments of walls, places of adjacency of the internal partitions to the outer walls.

I deliberately did not note Ukosin as a distinctive moment. Since in the American style, in the presence of sheathing with OSB3 plates (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.

The correct corners of the frame house

In fact, on the Internet, even in the American segment, you can find a dozen schemes. But most of them are obsolete and rarely used, especially in cold regions. I will single out three basic angle schemes. Although real, the main ones are only the first two.

Knots of corners of the frame house

  1. Option 1 - the so-called “California” corner. The most common option. Why exactly “California” - I have no idea :). From the inside, to the extreme pillar of one of the walls, another OSB board or strip is nailed. As a result, a shelf forms 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 - a closed corner. Also one of the most popular. The bottom line is an extra rack to make a shelf on the inside corner. Of the advantages: the quality of the insulation of the angle is better than in option 1. Of the disadvantages: such an angle can only be insulated from the outside, that is, it must be done before sheathe the frame with something from the outside (plates, membrane, etc.)
  3. Option 3 - “Scandinavian” warm corner. A very rare option, not used in America. Saw in the Scandinavian frames, but not often. Why did I bring him back then? Because, in my opinion, this is the warmest version of the angle. And I’m thinking about starting to apply it to our facilities. But before using it, you need to think about it, 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 the beam a bad option for the corner?

Corner from a bar, the most losing option

If you notice - in all three versions of 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 an angle will be the coldest. Secondly - if there is a beam in the corner, then there are no “shelves” inside to attach the interior trim to it.

Of course, the last question can be resolved. But remember what I said about the “wrong” frames? Why make it difficult, if it can be done easier? Why make a beam, creating a bridge of cold and thinking how then to attach a finish to it, 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.

Correct openings in the frame house

The openings and the upper harness - this is the most significant difference between the American skeleton scheme from the Scandinavian, 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 performed on the same principle).

Correct openings in the frame house

The first (1), which is usually paid attention to when talking about “wrong” openings, is the double and even built racks on the sides of the opening. It is often believed that this is necessary for some reinforcement of the opening for installing a window or door. In fact this is not true. A window or door will be fine on single racks. Why, then, need cohesive boards?

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

Figure 3 is one of the simplified versions when the bottom window trim crashes into a torn pillar. But at the same time, both window trimmings still have supports along the edges.

Therefore, one cannot speak formally about the fact that if the racks are not doubled, then this is “wrong." They can be single, as in the Scandinavian frame. Rather, a mistake is when the racks at the edges of the openings are cohesive, but do not bear the load from the elements resting on them. In this case, they are simply meaningless.

In this case, the horizontal elements hang 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 “incorrectness” of the opening. This is the “header" above the opening (header).

This is a really important element. As a rule, some load will come from above on the window or doorway - logs of overlapping the second floor, rafter system. And the wall itself is weakened by a deflection in the area of ​​the opening. Therefore, local amplifications are made in the openings. In American, these are 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 racks (if the classic American scheme with cohesive racks of openings is used), or are cut into the extreme racks, if they are single. Moreover, the cross section of the hider 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, built, extended in height, etc. - I repeat, it depends on the load. But, as a rule, for openings up to 1.5 m wide, a header from a 45x195 board is quite enough.

Is the absence of a hider a sign of a “wrong” frame? Yes and no. If we act according to the American principle of “simple and reliable”, then the header must be present on 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 at the edges of the opening - the load on top of the opening is minimal and you can do without a header.

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

Double upper harness

The double top harness from the board is also a distinctive feature of the American frame

Double upper harness

Сдвоенная обвязка опять же дает усиление по верху стены на прогиб от нагрузки сверху – нагрузка от перекрытия, стропил и т. п. In addition, pay attention to the overlaps of the second row of strapping.

  1. Crossing in the corner - we connect together two perpendicular walls.
  2. Center overlap - we connect together 2 sections of one wall.
  3. The overlap on the partition - we connect together the partition with the outer wall.

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

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

Correct mowing in a frame house

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

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

Why is such a mowing called “right” and what should I pay attention to?

  1. Such a jib is installed with an angle of 45 to 60 g - this is the most stable triangle. Of course, the angle may be different, but just such a range is the best.
  2. Ukosina crashes into the upper and lower harness, and not just rests on the rack - this is quite an important point, so we connect the structure together.
  3. Ukosina crashes into every stance in its path.
  4. At each node - adjoining to the harness or stand, there must be at least two fastener points. Since one point will give a “hinge” with a certain degree of freedom.
  5. Ukosina crashes into the rib - this way it works better in the structure and less interferes with insulation.

And here is an example of the most “wrong" mowing. Nevertheless, it occurs all the time.

It’s just a board stuck in the first opening of the frame. What is so “wrong" in it, because formally it is also a triangle?

  1. Firstly, a very small angle.
  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. Fourth, pay attention to the fact that in places adjacent to the frame extremely uncomfortable cavities are formed for insulation. Even if you carefully cut the jib and there will be no gap at the end, there’s no escape from an acute angle, and to qualitatively insulate such an angle is not an easy task, so this will most likely be done somehow.

Another example, also common. This is a jib cut into racks, but not cut into strapping.

Ukosina is not embedded in the harness

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

We will not even consider the options of any small inferior “mowers and struts” that do not reach from the upper harness to the lower harness.

Formally, even the most crooked jib makes a contribution. But again: why do it your own way if you already have a good solution?

This ends with the American frame and move on to the Scandinavian.

The right scandinavian frame

Unlike America, where the frames are almost 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 framework, in fact, is the development and modernization of the American. However, mainly when talking about the Scandinavian frame, we are talking about such a design.

Typical Scandinavian home kit

Corners, jibs - everything is like the Americans have. What to look for?

  1. Single strapping on top of the wall.
  2. Power bolt embedded in racks throughout the wall.
  3. Single racks on window and doorways.

In fact, the main difference is this same “Scandinavian” crossbar - it replaces both the American hider and the double harness, being a powerful force element.

What, in my opinion, is the advantage of the Scandinavian frame over the American? The fact that there is much greater emphasis on minimizing all kinds of cold bridges, which are almost all cohesive boards (double strands, racks of openings). Indeed, between each close-knit board, 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 the other question is when there are already two or three of them.

Of course, you should not get stuck on cold bridges. All the same, they can’t get anywhere and in fact often their significance is exaggerated. But, nevertheless, they are, and if it is possible to minimize them relatively painlessly, why not?

The Scandinavians in general, unlike the Americans, are very much confused on energy conservation. Affected by a colder, northern climate, and expensive energy. But the climate of Scandinavia is much closer to us (I speak primarily about the North-West region) than most American states.

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

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

“Semi-steering” frames

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

I will give a few examples.

An example of how to “overtake”

The first example from our own practice. This house was built by us, but according to the project provided by the customer. We even wanted to remake the project completely, but were limited in time, because it was necessary to go to the site, in addition, the customer paid a tangible amount for the project and there are no formal design violations, but he put up with the voiced shortcomings of the current solution.

Why, then, did I classify this framework as “semi-correct”? Pay attention to the fact that there are Scandinavian crossbars, American headers, and double strappings not only on the top, but also on the bottom of the walls. In short, here is the American scheme, the Scandinavian one, and another 30 percent of the Russian supply is thrown on top, just in case. Well, a team stand of 6 (.) Boards under the glued beam of the ridge speaks for itself. Indeed, in this place the only warming is isoplatings from the outside, and cross-warming 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 framework “semi-correct” because there are no complaints against it from the point of view of structural reliability. There is a multiple margin of safety “in case of atomic warfare”. But the abundance of cold bridges, and a huge overspending of material on 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 the framework according to the “double volumetric” framework system promoted by one Moscow company.

The main difference is actually a double outer wall, with racks 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 framework, can be solved by simpler, more reliable and correct methods such as “cross-insulation”.

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

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

“Wrong" frame houses

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

The quintessence of “directive” frame housing construction

What can be noted right away in this photo?

  1. Total use of material of natural humidity. Moreover, the material is massive, which most of all dries out and changes its geometry during the drying process.
  2. The beam in the corners and on the harnesses and even on the racks is the cold bridges and the inconvenience in further work.
  3. Lack of headers and amplifications of openings.
  4. Do not understand how the mowing made, poorly performing its role and interfering with warming.
  5. Assembly on corners with black self-tapping screws, the purpose of which is to fasten GKL during decoration (and not use in power structures).

The photo above shows the virtually quintessence of what is commonly called the “wrong” frame or “RSK”. The abbreviation RSK appeared a year in 2008 on the Federal Reserve, with the filing of one builder who presented a similar product to the world, called the Russian Power Frame. Over time, as people began to understand what was happening, this abbreviation began to be deciphered as Rashen Strasen Karkashen. As the apotheosis of meaninglessness with a claim to a unique solution.

What is most curious, if desired, it can be attributed to “semi-correct”: because if the screws do not rot (black phosphated screws are by no means a sample of corrosion resistance) and do not burst with the inevitable drying 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 “wrong” frames? If people understand what they are doing, they quickly come to the Canadian-Scandinavian scheme. Fortunately, the information is now in bulk. And if they don’t come, then this says one thing: by and large, they don’t give a damn about the result. The classic answer when trying to ask them a question, why exactly - “we always built like that, nobody complained”. That is, the entire construction is based solely on intuition and ingenuity. Without trying to inquire - but how is it generally accepted to do it.

What prevented a board from being made instead of a beam? Make reinforcements for openings? Make normal jibs? Collect for nails? That is, do it right? Indeed, such a framework does not give any advantages! One large set of not the best solutions with a claim to super strength, etc. .. Moreover, the labor cost is the same as the “right” one, the cost is the same, and the material consumption may be even more.


As a result: the “Scandinavian-American frame scheme is called“ correct ”, because it has already been tested many times on thousands of houses, proving its viability and the optimal ratio of labor-reliability-quality.”

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

As a rule, if potential contractors cannot justify the use of certain design solutions other than the “right” American-Scandinavian ones, this means that they have no idea about these same “right” solutions and build a house solely on a hunch, replacing knowledge with intuition and ingenuity. And this is a very risky way, which can come back to the future owner of the house.

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

And the main result is as follows:

Understanding what is usually called the “right” frame house, you can quickly understand who are the builders who really know the basics of modern frame house building, or self-taught people whose products originate in the camp huts of the Gulag ... and who have no desire to improve their qualification, taking advantage of the abundance of information on the Internet.

Floor device

Regardless of whether the house rests on a foundation slab or stands on stilts, the floor structure will consist of a bearing draft and decorative finishing floor. The rough floor is designed for load bearing. He holds the weight of the insulation, as well as communications, which can be built into it. For example, elements of a heating system, the so-called "warm floor" - electric cables or water pipes can be mounted in the floor.

Draft floor from boards.

The final floor is a decorating material. It does not carry heavy loads, but it covers the main supporting material, elements of the heating system, insulation and waterproofing, and also creates a look and supports the style. The floor material should be consistent with the overall decor of the room.

Rough screed

Rough concrete screed is performed on slab or strip foundations. In the tape version, the rough screed implies the absence of a subfloor or other empty space under the overlap of the first floor. In a slab foundation, the slab itself can function as a rough screed.

Rough floor screed.

Concrete subfloor is the most durable floor covering option. It can install any equipment, heating devices, heavy musical instruments. The concrete base can be laid cable and floor heating pipes.

The concrete floor has low thermal insulation. Concrete itself is “cold” and requires insulation. The concrete floor creates discomfort and “chills” the legs, so it is covered with a “warm” coating - wooden parquet, cork panels, insulated linoleum. Or equip it with a heating system "warm floor".

In addition, by hardening the concrete screed, you can vary its thickness, and this saves concrete. So, the use of reinforcing mesh provides the strength of a thin concrete screed with a thickness of 3 cm at the level of a thicker screed with a thickness of 5-6 cm.

Floor waterproofing

Concrete is able to absorb moisture and water. Soil water can rise through the pores of the material and causes the flooring to become damp. Therefore, the rough screed of the floor in the frame house is waterproofed in one of the selected ways - waterproof additives are added to the solution or insulating material is laid before pouring the solution.

Waterproofing the floor during construction.

Options for waterproofing the rough screed floor in the frame:

  • Before pouring concrete, Penetron-type moisture-resistant components are added to the solution. They form insoluble complexes with the components of the concrete mixture, which close the pores and prevent the rise of soil moisture. Thus, the concrete remains dry, which prevents wetting of the flooring, and also increases the durability of the concrete screed.
  • Before pouring concrete, a layer of rolled waterproofing (polyethylene, roofing material) is laid - this method is less effective, since it does not provide 100% moisture protection and has a limited insulation time. At its expiration - polyethylene and roofing material begin to collapse, lose a solid foundation.

Floor insulation

Insulation of the floor is necessary to limit heat loss during winter heating. It is provided for those frame houses in which they will live year-round. Warming can also use various heat-insulating materials:

  • Expanded clay - bulk natural and the most inexpensive option for warming the floor screed. It is poured over the ground with a layer of 300-600 mm. The thickness of the bulk layer is determined by winter temperatures. At medium temperatures around 0 ° C, 300 mm expanded clay is sufficient. At winter temperatures of -30 ° C, 600 mm of bulk insulation is required.
  • Polyurethane foam is the next low-cost heat insulator. For floor and foundation insulation, it is recommended to use its moisture-resistant forms - extruded Penoplex boards. They combine the function of insulation and waterproofing, and also serve a longer period.

Warm floor

There are two options for installing underfloor heating:

  • Так называемый электрический пол, в котором функцию обогревательных элементов выполняют электрические провода, силовые кабели, проложенные в толще пола, в его черновой стяжке. Такой пол отличается низкой инертностью. Он быстро нагревается и также быстро остывает. Его очень удобно использовать для дачных и сезонных помещений, когда необходимо за час-полтора нагреть пространство дома для комфортной ночёвки.
Electric floor.
  • A water or water floor in which space is heated by water pipes laid in recesses in the screed. This option is more inert. The water floor warms up longer and also retains its heat longer. Therefore, a water floor is best used for homes with year-round living. To heat it sometimes, occasionally, from time to time - is unprofitable and inefficient. Another advantage of a warm water floor is that it can be connected to any heat source. Be it a gas boiler, electric or wood-burning - heating pipes are connected to any heating device through which hot liquid moves.

And one more feature: an electric floor is equipped on top of a concrete screed (for safety and fire prevention). Therefore, for this type of heating, a foundation slab or tape with a rough concrete screed is necessary.

And now we will describe in more detail, how to make a warm floor in a frame house?

Electric cables or IR film

For electric floor heating use special power cables or infrared films, infrared panels. They differ from the cable installation, used for various floors. The cable is laid in a screed, and therefore used for plate and strip types of foundations. The film does not require the construction of a concrete screed, and therefore is used to heat the floor in pile-grillage frame structures.

Electric floor in concrete screed.

An electric power cable is laid inside the concrete screed. It is poured with a layer of concrete 50 mm thick, if necessary, reinforced. The outputs of the cable wires are connected to a temperature controller. Depending on the displayed readings, the controller periodically shuts off the current supply to the cable. Thus, there is an automatic adjustment of the temperature of the floor and the room. As soon as the heating reaches the set temperature, the controller turns off the electric current, the screed of which continues to radiate heat without heating. As soon as the temperature drops, the controller resumes the current supply and the screed is heated.

The film is laid on top of any surface, on a concrete screed or wooden beam. It also fits onto the floor of the second floor, which is often equipped with boards, OSB and plywood in frame buildings. Such a warm floor is called "film", it is often equipped on light floors. This is the most successful option for heating the upper floors of light frame buildings, attic rooms.

The infrared film is not glued to the base and is not concrete in the screed. It is laid on an existing rough floor - a concrete slab, wood, or a slab of DSP, or OSB. And on top they close with a fine floor covering - laminate, linoleum.

To control the temperature of the floor and room heating, the infrared film wire outputs are used. They are connected to the heating controller and automatic on / off similarly to a cable.

Warm water floor

Water pipes are a modification of traditional heating with metal batteries - radiators. It can be laid on concrete and wood, on top of concrete slabs on the ground floor or between wooden planks of the floor. On the floor logs in the frame house lay a rough ceiling, which is collected from strong boards with a thickness of 50-60 mm. On top of the boards - put water pipes. On top of the pipes is decorative flooring.

For the underfloor heating system, metal-plastic pipes with a diameter of at least 20 mm are used. They are placed either in the floor screed of the first floor, or in the grooves between the wooden boards of the draft floor of the second floor of the building. The ends of the pipes are connected to a heating device.

The scheme of the water floor from the boiler.

Each room has its own “loop” of heating. At the inlet and outlet, the heating devices are connected to the collectors. They distribute water between the rooms of the frame house, and also take it from the same rooms. Further, water passes into the boiler, where it is heated, and again leaves the collector.

Laminate flooring

Laminate - The best option for flooring heating system "warm" floor. It is a wood-containing material, a fiberboard under a wear-resistant synthetic film. It is produced in the form of plates with a special edge. The edge of the plate has a groove-tongue system that allows you to conveniently assemble the floor, “snap” adjacent panels into each other. An important advantage of the laminate is that its pattern can imitate various types of wood, a board, parquet, and cork.

Linoleum on the floor

Linoleum - the cheapest polymer coating for a "warm" floor. It differs in some water resistance, therefore parts are used for household frame rooms - a corridor, a kitchen. Also allows you to simulate various materials and surfaces. At the same time, it has a more affordable price.

For floor heating devices use linoleum without a substrate-insulation. If you have a concrete floor without heating, it is better to use linoleum with a foam base or lay it on top of plywood.

Sub floor structure

The structure of the floor device in the frame house does not differ from the walls.

There are also power elements responsible for the reliability and strength of the structure - logs and jumpers. They are also attached to the supporting base - the foundation. And in the context, this is the same sandwich - a thin-layer skin of the frame, inside of which there is a heater. And so that the insulation and wood do not get wet from condensation and atmospheric moisture, they are protected with special films and membranes.

Equip the rough floor in the frame house in two stages.

Features of the rough floor of the first floor. First stage

At the first stage, immediately after completion of the construction of the foundation, a supporting floor structure is installed - logs and crossbars.

It looks like a simple "skeleton" of the floor of the first floor

And here there are different options for attaching them:

Logs are fixed on top of the pile foundation strapping beam or the laying of the strip foundation on nails. First, along the two opposite walls, a facade (strapping) board for the lag is fastened to a timber or bench. And then the lags themselves set in between them. If necessary, they are increased with an overlap, which should rest on one of the internal bearing walls of the strip foundation or the internal beam of the grillage (run).

Scheme with fastening lag to the facade board

On our site you can familiarize yourself with the most popular projects of frame houses from construction companies represented at the exhibition "Low-Rise Country".

Video Description

The rigidity of the structure is ensured by additional struts, the length of which must correspond to the step of the lag (minus their thickness). How Larry Hon does this can be seen in the video below:

Logs are mounted on top of a strapping beam or bed, fixing them directly to the wall posts on nails and brackets. In this case, the layout of the lag completely coincides with the pitch of the racks, and this is not always "convenient".

Racks and logs in one mount

The lags are fixed in the strapping beam, for which they make special slots.

Logs are attached to the strapping beam on the inside, using special brackets.

As for the lag layout step, there is no unequivocal opinion.

A more “economical” option is 600 mm. And if we talk about the axial distance, then taking into account the thickness of the lag - 625 mm. But some experts recommend a pitch of 400 mm. And although it is necessary to cut the mats when warming mineral wool, the design of the rough floor will be much stronger.

Important! In places of installation of heavy equipment (stove, fireplace, floor boiler with a boiler), the layout (step) of the lag is additionally reduced.

Installation of the rough floor. Second phase

The second stage of arranging the subfloor is started after the walls are standing and the roof is mounted. Although frame houses are prefabricated, precipitation can "happen" at any time, and mineral wool must be laid on the condition that it does not get wet from rain.

There are three ways to make a floor in a frame house (more precisely, its lower part):

The base hem the bottom lag. It is made from boards, moisture-proof plywood or OSB. Since decorative qualities are not needed for this, the board can be taken unedged, but be sure to remove the obzol (bark) and treat it with an antiseptic. All the load that will fall on this base is the weight of mineral wool. Therefore, it is enough if the board will be 20 mm thick, and plywood or OSB - 10-15 mm. The disadvantage of this method is that the base is fastened from the side of the subfloor, and this is possible only with sufficient clearance to the ground.

This is how the floor layout looks like with bottom hem

Binding of the base is carried out on the "cranial" bar. This is the name of a small block in cross section (usually 50x50 mm), which is attached to the logs on the side wallpaper at the very bottom. Planks of the base or cut plywood sheets (OSB boards) are laid on these bars. Moreover, their attachment to the cranial bar is carried out purely "symbolically." The advantage of the method is the installation "from above", so there is no restriction on the clearance between the ceiling and the ground. The disadvantage is that the logs must be at least 200 mm high (even better - 250 mm) to compensate for the loss of usable space for floor insulation. It can also be noted as a drawback the additional purchase of the bar.

Skull sub floor plan

Draft cakeflooring frame housemounted on top of the lag. This method is used if the base is low and there is virtually no subfloor. In fact, it is necessary to lay additional logs perpendicular to the lags of the main draft floor. In this case, the base of the subfloor is attached to the main logs, and additional logs are mounted on it - they serve to fix the finish floor covering.

After the base is mounted, a waterproofing membrane and insulation are laid between the lags (basic or for the third method - additional).

It might be interesting! In the article at the following link, read about how to insulate the floor in a private house.

First floor sub floor cake

The correct arrangement of the layers of the wooden floor of the first floor looks like this:

diffusion waterproofing membrane

insulation between the lag,

directly the sub floor itself, as the base of the finish floor covering.

Note. If a floor tongue is used as the finishing coating, then it is mounted on the logs over the vapor barrier.

This arrangement protects the heater from the penetration of water vapor with warm air from the side of the room, and does not prevent them from weathering out into the underground.

Mineral wool, ecowool, regular or extruded polystyrene foam are chosen for the floor of the frame. Mineral wool is preferred because of its incombustibility. But if you need to make the floor warmer with the same thickness of thermal insulation, then use a combination of expanded polystyrene and mineral wool. At the bottom put 10 cm thick foam, and on top of mineral wool.

It might be interesting! In the article at the following link, read about how to paint a wooden floor in a house.

Draft floor of the second floor

The device for the subfloor in the frame house on the second or attic floor is different from the basement.

Here the vapor barrier is located differently and additionally there should be elastic gaskets to compensate for shock and structural noise. In addition, only mineral wool is used as an insulating layer. Moreover, this is due not only to its incombustibility, but also to the ability to absorb airborne noise, which the foam does not have. That is, it acts not as thermal insulation, but as sound insulation. Therefore, its thickness will be less (although for this case it is better to choose mats of special acoustic cotton wool).

Soundproofing is important for flooring and floors on the second floor of a frame house.

Note. Airborne sounds include any waves in the acoustic range - this is speech, music, a working TV or a music center. Shocking noise is walking on the top floor, sounds from objects falling onto the floor or furniture being moved. Structural noise propagates through structural elements from operating equipment (ventilation, air conditioning, pumps, water supply and heating).

Recommended in terms of sound insulation sequence of arrangement of floor layers of the second floor (top down):

fine finish (for a laminate - with a foam polyethylene backing),

plywood or OSB cooker,

rubber or cork substrateglued over a chipboard (or plywood) plate,

rubber or cork laying on floor beams,

mineral wool between the beams

ceiling cladding (drywall, lining or panels),


The rough floor must be reliable and durable - its main elements are part of the supporting structure of the frame house. In addition, it should have good heat and sound insulation properties - it is precisely the observance of this part of the conditions that is responsible for comfort. Therefore, everything here must be done on the basis of a project, the calculation of which should be carried out taking into account the regulatory requirements and climatic conditions of the region. And this is a job for professionals.