Wooden beams on the floor for a large span. How to properly insulate wooden beams, interfloor floors? Wooden floor between floors

When constructing a roof, special attention is always paid to the construction of the attic. After all, it is important that its overlap is done technologically correctly, does not exert excessive pressure on the walls and be able to bear the load from the things stored under the roof and sometimes a whole set of furniture.

Therefore, in this article, we will figure out in detail with you how the attic floor should be arranged correctly on wooden beams: the features of its installation, calculation of loads and fastening. And our detailed illustrations will help you.

To begin with, we suggest that you watch a small video review of the attic floor device on wooden beams, and then we will analyze the details:

What is a ceiling for an attic?

The overlap is a horizontal load-bearing structure that separates the residential floor from the attic, and at the same time takes on the load from the weight of everything that is under the roof.

The floor itself is a necessary stiffening element, which also provides stability to the entire structure. Among all the others, today we will single out the attic floor, namely, its specific appearance. Note that the general rules apply to all types, but there are still some technical features in arranging the attic floor over beams.

The first is rigidity and strength. Those. the overlap should be:

Able to withstand the design loads and at the same time not bend, will not collapse. For example, the allowable deflection is only 1 in 250 of the span length.
Secondly, the attic floor should not be flimsy, and in no case should it fluctuate when moving objects on it or the movement of people.
And finally, soundproofed to avoid unpleasant squeaks when someone climbs into the attic.

In private construction, two types of floors are mainly used: wood and reinforced concrete. The former are lined up along solid wooden beams, and the latter - along beams, slabs and in a monolithic version. Also, the beams themselves can be steel if you have to bridge large enough spans. But it is in private housing construction that the choice of floor material is most often influenced by the economic factor.

The cost of installing floors is usually up to 20% of the estimate of the entire construction of a house, and labor costs as much as 25%. Therefore, the construction of a wooden attic floor is still quite popular - all thanks to its high performance characteristics and good sound insulation.

And one more important point: in the manufacture of wooden attic floors, you do not need heavy lifting equipment, especially a concrete pump.

Benefits and calculation of beam floors

The whole structure consists of beams and boards, which are called rough. The beams themselves can be load-bearing, located just side by side, or fixed in a special way, which is much more reliable. Standard dimensions of beams are 20-40 centimeters high and 15 meters long, plus 8-20 centimeters wide.

Unlike reinforced concrete attic floors, wooden ones are dry-mounted. By weight, it comes out much lighter, so in private construction it is better to use just such an overlap. On the other hand, wooden floors are the most soundproof, so you will have to spend money on additional measures.

Beams are located at a distance of 60 centimeters to 1.5 meters. Of course, the more often you install them, the greater the load the attic can withstand in the future, but the foundation of the house will have to endure a greater load.

On a wooden attic floor, lightweight partitions are usually mounted - most often frame ones, to which the attic rafters are attached directly. They need to be installed perpendicular to the beams or an edge.

But if for some reason the inner walls of the attic have to be placed parallel to the ribs or beams, which is not at all according to the rules, then the structures in these places must be strengthened. Most often, fragments of boards are used as such elements, which are fastened perpendicular to the edges of the floor.

Installation options for attic beams, depending on its type

Many people ask the question: where to install wooden floor beams correctly? Into the walls, on the walls, or even bring them out a little? It depends on what kind of attic you will have and whether you will use it as a living space in the future. The attic is very popular today!

So, here is an economical option that allows you to convert an attic into an attic in the future without any problems. True, very close:

And therefore, if you have such plans and you are not even now sure whether there will be another place in the project for a personal account or a billiard room, then make the walls higher in order to install the floor beams lower.

What will it give? In such an attic there will be much more usable space, fewer sharp corners and it will be much warmer:

But if in your project the attic was originally planned as a separate and spacious room, as if built on top of the house, then the attic beams need to be installed as strong as in the interfloor overlap, and they should also be fastened to anchors in the armored belt:

Here is a great step-by-step example of how such attics are built and how strong such an overlap should be:

Types of floor structures

In total, there are several types of attic floors on wooden beams. Each of them has its own purpose and its pros and cons.

Platform: for a cold attic

As for frame houses, the floors in them are recommended according to the "platform" system. That is, after installing the walls, beams are laid and a platform, as it were, is created, and a working base for the future attic floor at the same time. It is important here not to put too much pressure on fragile walls, so the attic floor will also not be designed for a piano in the corner.

In this case, the beams are installed on a strapping beam, which is used as a Mauerlat:

Rigid shield: for uniform shrinkage

But in a house with walls made of logs or beams, a rigid shield is arranged as an attic floor according to the rules, which, when the walls shrink, will smoothly descend with them, and necessarily evenly.

Economy flooring: to save time

Pre-fabricated wooden floors should be distinguished as a separate type of attic floors. Their main feature is the use of special fasteners, which are made of galvanized steel. Their thickness and quality are calculated depending on the level of future floor loads.

Standard attic floors on beams with beams and wooden joists appeared at the end of the 20th century, and after them wide board ceilings became more fashionable.

Ready-made trusses: for residential attic

Today, special ready-made companies for arranging the attic floor are also in fashion. In fact, this is not a novelty in the construction market, such firms appeared at the end of the 16th century and found their rebirth at the end of the 20th century. Canadian construction companies have developed special calculation programs for such firms and their exact shapes with assembly lines.

Ribbed-girder flooring: for private housing construction

In our country, new types of wooden floors are beginning to appear, which until that time were popular only abroad. These are lightweight hardwood floors. They are relevant for private construction, when a fairly light wooden frame is used as a system.

The essence of the overlap is that the "ribs" are installed every 30-60 centimeters, and they are covered with sheathing. Wooden beams with a height of about 20 and 28 centimeters, and 45 centimeters thick, and up to 5 meters long are taken as "ribs". They are made from natural wood and connected with special bundles from boards, covering with sheathing of chipboard or fiberboard.

Therefore, we will single out from the main advantages of the ribbed attic floor, quick and easy installation. Of the minuses: the need for processing with a fire retardant, lower strength and low sound insulation properties. And, of course, such boards are more sensitive to sudden fluctuations in humidity and temperature. And also, if a fungus or some insect decides to eat such an overlap in a few years, then it will eat it much faster than thick beams.

From below, such a structure is sewn up with a suspended ceiling made of gypsum plasterboards. Mineral wool is placed on top between the ribs. It is she who will provide fire resistance and sound insulation to the entire wood floor.

Ribbed attic floors are much cheaper than beamed ones - this is quite reasonable and rational if you do not insulate the non-residential premises and make a residential attic out of it. Then you don't have to worry about the bearing capacity of such a foundation. The only drawback is that beams are more familiar to Russian houses, and the ribbed flooring is almost the same in appearance from the monolithic one. Therefore, in Russian houses, ribbed-beam attic floors are more often arranged.

A beam for the device of such an attic floor must be taken in a rectangular shape, and strictly, and not a diamond. And be sure to take with you the most ordinary school ruler when buying such a bar, because it often happens that many are going to build a ceiling from a 15x15 cm bar, and as a result are built from a 14x14 cm bar.And then, on your site, be sure to prepare a storage space such a bar and its processing.

By the way, today many even put an ordinary beam in a wooden floor on the edge. The fact is that even a ruler, no matter what material it is, bends easily along its entire length, but if you put it on the edge, it will be almost impossible to bend it:

And on the sub-floor of the planks, already lay the final floor, and mount a suspended ceiling from below. But often the wooden ceiling of the attic is left without additional finishing on purpose, in view of the concept of interior design, but then all its details are done very carefully and even with a decorative slope:

The suspended ceiling itself gives a certain rigidity to the ribbed ceiling.

How to embed attic beams into walls of different materials?

Today, there are several ways to attach attic beams. Basically, it is necessary to install a perpendicular support beam, which is equal to the maximum length of the floor beams. If the project does not provide for additional stiffening beams, then the beams of the attic floor should lie along the axes of the racks of the load-bearing walls. By standards, the floor beams must rest on the upper wall trim and fasten to it with two nails 3.5x100 mm on each side.

But often, in construction, you also have to use special fastening methods, and in order for you to better deal with them, we have prepared high-quality master classes for you.

It is necessary to design a wooden attic floor based on the loads that will affect it. But consider this moment. Quite often, residential buildings are built with the expectation that there will be enough for the whole family. And such loads are divided into distributed and concentrated.

When designing an attic floor, you need to take into account distributed loads, and you can learn more about them from modern SNiPs. Concentrated loads need to be taken into account only if you are definitely going to install some objects with a large mass in the attic.

For example, today it has become fashionable to arrange under the roof SPA salons, billiard rooms, dance floors and rooms for music training. But in practice, it often turns out that 10 rooms in a house is not enough. And under the roof there is wonderful ventilation, a beautiful space and quiet to equip your personal office there.

The need to use special fasteners depends on which technology for arranging the attic floor you chose in general. So the most reliable way is to support the beams on the bearing surfaces of the walls or on the floor beams. Then there is no need or sense at all to use metal elements - the beams are fastened with screws or nails. In all other cases, it is imperative to fix the attic floor.

Therefore, we advise you to initially make such a strong attic floor, so that in a couple of years with a clear conscience, rebuild it into an attic. And our special tables and computer programs will help you to make special calculations. Your task is to choose the right optimal cross-section of the beams and their pitch. All the rest are details.

Is a reinforced belt required?

First of all, decide if you need an armored belt to install the attic floor beams. Armopoyas is a reinforced belt, which is a closed structure along the entire contour of the building. The task of such an element is to distribute the loads.

When installing wooden beams of an attic floor, it is necessary to install an armored belt only if:

The walls of your house are built from aerated concrete or foam block. After all, such a material has a rather fragile structure, and a timber beam floor at the same time has a considerable weight. Due to its design, it always creates a point pressure on the blocks. And our task is to distribute this pressure and make it linear. So that the Mauerlat takes over the entire load.
Also, whether there are prefabricated FBS blocks as a foundation for your house, or the base itself is shallow, it is also important to correctly distribute the load from the attic over the entire area of the base of the house.

In all other cases, you can safely do without an armored belt.

Fastening beams to beams or frame

When the floor beams are attached to a log house or rounded logs, the easiest way is to use the frying pan technology. In simple terms, simply insert beams into walls as part of a constructor.

Please note that the floor beams are fastened together with metal brackets:

Fastening to metal I-beam

If you have to break the floor beams along the length, then their parts should be overlapped or with the help of special overlays, and between the beams themselves you will also need spacers.

And if we are talking about planning a large area, then it is better to use a steel I-beam or an especially strong one made of glued wood as a support for the beams. In this case, leave a gap of 10 millimeters between the attic beams and the steel I-beam. It is important, however, that the steel beam does not touch the ceiling sheathing. And, so that in the future the floor beams do not creak, lay additional sound-insulating material or make the ceiling lath rather dense:

If you are using construction beams, they do not need to be placed inside the floor. These can be easily built into the wall or even used independently. And the beams themselves must be fastened to the so-called beam shoes:

The first step for such beams is to make a strapping. Moreover, it is not at all necessary to fasten the strapping itself to the walls of the first floor, as many think.

The main thing is to properly prepare such beams for installation. And for this they must be treated with an antiseptic (and at a temperature of at least 5 degrees Celsius). Then leave them to soak for a day. Now cut and lay such boards and the supporting beam on a wooden Mauerlat, previously impregnated with its fire-retardant protection. It remains only to fix all the floor beams on the shoes.

And, when the overlap of the beams is ready, make a rough floor, at least so that it is convenient to move on it.

Fastening to brick walls

If we are talking about attaching a wooden beam to a brick wall, then a nest must be created in that, and even at the stage of erecting the walls themselves. The nest should be 160 mm inside the wall (this is the minimum), and on a special board.

When inserting a beam into a wall, you need to fill it with cement mortar or leave it open - it all depends on the thickness of the wall:

So, a closed version is necessary with a wall thickness of two bricks.
Open - with a wall thickness of two and a half bricks.

In addition, the joist ceiling of the attic with brick walls must be reinforced with anchors in every third beam. The anchors should cover it from below and on the sides, and they themselves should go into the wall by 30-50 millimeters. It is also possible to connect the beams to each other and on the interior walls.

Beams should be fastened to a brick wall using the following technology:

Fastening to fragile block walls

If you are fixing wooden beams in a block wall, then you need to build a reinforced concrete lintel. This is the same reinforced belt that we talked about earlier. You need to arrange it under a beam, specifically under a wooden box that goes into the wall. The beam itself will need to be installed on a reinforced belt in the wall, also for a minimum of 160 mm. And do not forget also about such an important point as the insulation on the side of the block and the gap on the side of the beam, which will ensure the release of moisture.

Therefore, in order for modern lightweight blocks to withstand the wooden beams of the attic floor, follow this pattern:

If the blocks are quite strong and are close to brick in their physical qualities, then use the following installation scheme:

Which timber is better to choose for overlapping?

If you have now smoothly approached the issue of attic flooring, the first problem you will have to face is finding good quality boards. It is very important that neither the beams nor the flooring are flawed, weakened and certainly not sore with any mold. Otherwise, such overlaps are life-threatening for the life of household members.

Option # 1 - beams from ordinary boards

Let's separately note which beams you need to use when arranging the attic floor. The best option is boards 20-30 centimeters wide. Pine or larch is taken as a material, which work well for deflection. It is such wood that is strong in terms of deformation and less prone to cracks. According to official estimates, when using such a material, it turns out to reduce the consumption of all wood by as much as 20%.

Option # 2 - laminated veneer lumber beams

Today, glued laminated timber is also often used as beams, the strength of which is several times higher than the strength of ordinary wood. The thing is that any glued wood products are stronger. The whole secret is that the glue that is used gets into the pores of the two parts to be glued and forms many strong threads between them - much stronger than the fibers of the wood itself. And therefore, glued laminated timber as beams is a completely normal option.

In appearance, they do not differ from solid wood, especially when for the purpose of aesthetics in the outer layers they use wood of the best grade. Such beams are made from lamella boards, which are cleaned of defects and glued together. The main advantage of this method is that the total length of the beams can now be up to 12 meters, and it will be much stronger, just with a wooden beam with the same parameters.

To make strong beams from OSB boards, they are cut into strips of different widths and milled. Next, the blanks are glued together, and they form a long endless strip, from which templates of a certain length are made. The main advantage of using such beams for attic flooring is low weight and excellent strength and bending resistance.

Option # 4 - I-beams

Another type of beams that are popular in Russia are I-beams. This is one of the most durable types of beams, and you can arrange any kind of flooring on top of them, not just plywood. And plasterboard is hemmed from below. These beams are so strong that it is more advisable to install them as an interfloor for fully living rooms, but not only for the attic, and even more so for a cold attic.

The so-called Canadian I-beams are also popular. They are made in the factory from wooden blocks, OSB boards, special moisture-resistant boards, laminated veneer lumber or softwood.

Option # 5 - beams from ready-made trusses

For example, one of the most recent developments is turnkey loft trusses. Their height is 350 millimeters. They are made of dry wood with a section of 100x50 mm. In the factory, on a special press with metal plates, such elements are combined into one structure. Moreover, in the process of manufacturing such farms, engineering communications are even placed inside them.

Option # 6 - LVL beams

Separately, it should be noted that a relatively new material on the domestic market is LVL beams. These are high-strength homogeneous materials that are made by gluing under special pressure. Several layers of veneer are taken into account, and in the process of manufacturing the beams, the fibers are located strictly parallel.

The characteristics of such beams are special. The main advantage is that which beams are available in a wide range of sizes. The material itself lends itself well to processing with almost any cutting tools. But considering the price of LVL timber, we advise you to purchase it only if your attic floor is located above a large span and your priority is quality and safety.

Option # 7 - HTS-beams

Another new type of attic beams is the German HTS. They also represent an I-beam, where the upper and lower layers are made of wood, while the middle layer is made of OSB boards.

Between these layers, a profiled steel sheet 0.5 mm thick with a special polymer coating can also be inserted. At the same time, the steel itself has a wavy shape, due to which the beam has high bearing characteristics. And there may not even be one such walls, but two, which is even better for bending resistance. And so that the HTS-beam does not bend or twist, hidden cross-links are installed between the layers with a certain step.

A high-quality interfloor overlap in a wooden house depends on the correct calculation, the choice of material and the accompanying layers of thermal and waterproofing. An independent device is possible if the following rules and process steps are followed. Also described are the common mistakes of homebrew masters, warning that it is easy to achieve safe operation.

The choice of material for beams and heat-waterproofing raw materials

Professionals know very well that overlapping in any object must have the following qualities:

Reliability in terms of the weight of the superstructure, the placement of household items, the frequency of operation. That is, if the second floor is determined to be a residential-type room - bedrooms, nurseries, offices, then the wooden beams must have a cross-section of at least 150 mm.
Have a permissible deflection of 0.7% of the opening. These are the rules of SNiP. The structure of interfloor floors, having a margin of lateral rigidity, transfers it to all load-bearing elements.
Fire resistance, hydro, heat and vapor insulation are important companions of beams, therefore, the interfloor cake in a wooden house has a complex configuration and does not tolerate deviation from the rules of laying.

The type of object is also important - frame, timber, log. Accordingly, the raw material for the rigid bond is selected.

For profiled solid wood, this is a bar with a length from 2.4 m to 3.6 m, glued - 4.2-6 m with a section from 150 mm to 200 mm. The logs should be covered with the appropriate material, which will also look aesthetically pleasing.

Floor insulation

The spans between the floors of any building are both the ceiling and the floor at the same time. Accordingly, the layering of insulating materials varies. For the load part, that is, the floor, the following raw materials are used:

Inch boards (depending on the weight of the furniture, they are changed to a more impressive thickness).
Moisture resistant plywood in two layers.
Cork soundproofing between plywood boards.
Waterproofing.
Finishing floor.

Accordingly, the lower part, which is the ceiling, will be less loaded, since it is devoid of exploitation:

Vapor barrier.
Drywall sheets.
Finishing material - block house, lining.

The construction market is full of proposals for insulating and finishing materials. You need to choose according to your wallet, but at the same time do not save on quality - wood is a capricious material.

DIY installation of interfloor floors

The design of interfloor floors is a responsible business, therefore, the following steps are required to be performed without fail. So:

The installation of niches for inserting beams takes place on the longest walls, that is, the logs should be proportional to the smaller wall parameter.
The pitch of timber installation should not be less than one meter; for large spans, the laying width is provided for up to 0.5 m.
Niches are cut by hand using an electric saw. It is universal for both timber and solid logs.
Next, the beams are inserted. The ends of the lag are wrapped in two layers of roofing material or other material, so that the edges of the insulation on the inner side of the wall protrude by 4-5 cm. The fastening takes place with anchor bolts.

On the beams, cuts are made in advance for inch transverse boards in increments of 40-60 cm. The ends should lie exactly in the middle of the end.

Next, you should fill the boards from the side of the ceiling. Thus, two goals can be achieved - to make a rough covering from the bottom and to provide space for the sectors for the insulation tab. As this, mineral plates or styrenes are purchased, which are the best in their class in terms of heat capacity.
Then, after the slabs are laid, moisture-resistant plywood follows, between which cork sound insulation is laid - the best in the class of sound damping. Plywood should be staggered with seams.
Now the floor needs to be protected from possible moisture. For this, waterproofing is lined - polyethylene, rolled rubber - it will work as depreciation or another product for this purpose. Attach the protective layer with tape or a furniture stapler, which is more reliable.
It is now the turn of the finishing coat. If the general finishing work has already been completed, then you can use roll-up decorating surfaces - linoleum. When finishing is still to be done, solid raw materials are laid on the prepared platform - tongue-and-groove boards, laminate, parquet and so on.

Now the lower surface - the ceiling - should be brought into proper condition. It is not worth sealing or tamping the roughing boards tightly - the gaps will create the necessary ventilated channels for the wood.

A vapor barrier is laid on the surface. It will prevent fumes from the inside from humidifying the ceiling.

In this capacity, a foil membrane is used. It is fastened with the shiny side outward with a furniture stapler.

Now you can proceed directly to decorating the ceiling. The budgetary and most common option is gypsum board ceiling upholstery.

Necessarily marked as moisture resistant. A more aesthetically pleasing interfloor ceiling in a wooden house will look like a clapboard or block house of natural origin. Thus, the ecological component is fully observed.

It is clear from what has been written that editing is not difficult even for non-specialists. Using a quality tool and accurate measuring instruments, you can achieve a professional result.

Errors in the construction of wooden floors

With an independent device of any design, there is a real chance to save your own budget. However, with a proviso - with a professional approach.

Beginners can make a lot of mistakes, in which the interfloor floors of a wooden house will become not only unreliable, but also pose a danger to residents. So, what are the tricks of a good installation:

The most important mistake will be the device of beams closer than 40 cm to the chimney. Wood, as you know, burns and this does not always happen due to an open flame - heating and charring will cause smoldering and it is not far from trouble. In addition, the surface of a brick chimney must be plastered with special compounds to a minimum thickness of 2 cm.
The wood for the lag must be perfectly dry. If you purchased it without confidence in this, then you should wait up to six months, setting the raw materials on stands in a dry and ventilated room. Installing wet whips is fraught with the whole structure of the house, especially when it comes to a log cabin.
Treat future floors for protection from rot, fungus and bark beetle. Even if the seller assures that the goods are processed in the best possible way, this does not mean that you need to take their word for it. Then, in case of adversity of all the described types, professionals will have to open the floors and "heal" the beam.

All photos from the article

Interfloor wooden floors are very popular due to the ease of their installation and the cheapness of the material. However, it should be borne in mind that the floor is one of the most critical elements of any building.

Therefore, before proceeding with the installation, it is necessary to study the basic building rules for wooden interfloor floors, which we will familiarize ourselves with below.

General information

Dignity

The main advantage of wooden floors is that they are easy to install without the use of special construction equipment.

Moreover, they can be used not only in wooden houses, but also in buildings made of the following materials:

Brick;
Lightweight concrete;
Ceramic blocks, etc.

Of course, you can't make an interfloor overlap in a wooden house with your own hands alone. But two strong men with experience in construction work can easily cope with such work.

In the photo - floor beams of a wooden house

disadvantages

As for the shortcomings of the design in question, they include the following points:

I must say that despite all these shortcomings, subject to certain installation rules, the interfloor floor from wooden beams turns out to be strong, reliable and durable.

Features of the device

Materials (edit)

First of all, let's get acquainted with the materials that can be used for the designated purposes. The fact is that strict requirements are imposed on the beams with respect to quality and strength, since they only rest on the walls with their ends. For these reasons, hardwoods are not suitable for wood.

It is allowed to use only coniferous timber, which has been dried for at least a year. The ideal option is considered to be a bar that has been dried for three years.

You can get acquainted with additional useful information on the voiced topic from the video in this article.

Private low-rise construction has become more and more popular in recent years.

Country houses and summer cottages, erected by their own hands, occupy an increasing share in the total volume of housing commissioned.

The most demanded material in private construction is wood, due to its affordable cost and ease of processing. But not all individual developers have sufficient experience and knowledge to independently carry out the entire range of construction work. So, the question often arises of how to properly lay the floor of the second floor in compliance with all building standards and technologies.

Construction requirements for hardwood floors

To assemble a durable and safe wooden floor between the 1st and 2nd floors with your own hands, you must strictly observe the technical requirements for them.

Thermal insulation layer

Thermal insulation of the floor will improve the temperature indicators in the room on the second floor

If the wooden floor separates the upper and lower rooms with a temperature difference between them of more than 10 ° C, it will be necessary to build an insulating layer.

This is necessary, for example, when arranging floors between the first floor and the basement, basement or between the first / second floor and an uninsulated attic.

Strength of beams

Beams and ceilings must withstand up to 180 kg / m2 load

When constructing the floor of the second floor on wooden beams, special attention should be paid to the strength of the supporting structures. The safety of the building depends on how strong the wooden floor beams are.

According to building codes for low-rise wooden buildings, the maximum load on the first floor slabs should not exceed 210 kg per sq. M., The pressure on the wooden floor of the second floor should not exceed 180 kg / sq. M., And for attics and attics this indicator should be less than 105 kg / sq.m.

Maximum deflection

In addition, building codes also impose requirements on the deflection values of wooden floor beams. According to SNiP, this coefficient should not exceed 1 to 250. That is, the maximum deflection of wooden supporting structures during operation should be less than 4 mm per meter of beam length.

According to this standard, the deflection of a beam structure with a length of 4 m in the center should not be more than 1.6 cm (4 m: 250 = 0.016 m). If it is planned to place massive furniture and household appliances in the room, flooring as a floor covering for tiles, etc., then the requirements for the rigidity of the structure increase to 1 in 400.

That is, the deflection should not exceed 2.5 mm per meter. For non-residential attics and attic spaces, a larger deflection coefficient is allowed - 1 to 200 (5 mm per 1 meter).

Soundproofing

Fifty-millimeter mineral wool will not only insulate the floor, but also become a good sound insulator

According to building regulations, the sound insulation threshold for interfloor floors in residential buildings should be 50 dB.

To meet this requirement, it will be enough to cover the floor of the second floor under the finishing coating with 50 mm thick mineral wool.

The length of the beam should be no more than 5 m

The maximum allowable length of free sag of wooden beams should not exceed 5 m for interfloor and 6 m for attic floors. If the project length of the room is more than 5 m, it will be necessary to install an additional support under the load-bearing beam. The fact is that the optimal length of the supporting wooden structure is 4 m.

With a further increase in its length, the rigidity and strength of the supporting structure sharply decreases and the requirements for the thickness of the beam section increase disproportionately. So that the deflection indicators for 8 m of the bar "fit" into the SNiP standards, its thickness should be about 40 cm. For example: the same deflection indicator shows a 4 m bar with a section of only 15 x 15 cm.

Wood is a material that is quite vulnerable to external influences, primarily dampness and fire, therefore, before proceeding with the construction of load-bearing structures, all wooden elements must be treated with antiseptic materials and fire retardants.

Construction material

Before proceeding with the construction of the floor on the second floor with wooden beams, you should make a list of all the necessary materials. This will allow during work to avoid unexpected downtime and delays caused by the need to buy some building materials.

Beams

A 15 x 15 beam section will suffice

The basis of the entire structure of interfloor wooden floors is beams. They play the role of load-bearing elements, and the strength of the structure depends on them. For them, a bar or carriage with a section of 15 x 15 cm, or 18 x 18 cm is usually taken.

This section is usually sufficient to provide sufficient rigidity with a specific load of 400 kg per square meter. In this case, it is necessary to comply with the parameters recommended by building codes: the span length is 4 m, and the step between the beams is 60 cm. Based on these parameters, you can also calculate the required amount of timber.

№	Span length (mm)	Beam cross section (mm)
1	2000	75 × 150
2	2500	100 × 150
3	3000	100 × 175
4	3500	125 × 175
5	4000	125 × 200
6	4500	150 × 200
7	5000	150 × 225

However, in the absence of a beam and small values of the expected loads on the floor, it is quite possible to use boards knocked together in pairs and placed on the edge with a thickness of 50 or 40 mm. This option is suitable for flooring in the attic or in a small country house.

For the first floor of a residential building, this option is not suitable due to the low load-bearing capacity of the boards: to ensure the required rigidity, you will have to significantly reduce the step between the plank beams, which will lead to unnecessary waste of material.

Pine is most often used as a material for beams. This is the best option in terms of price-quality criterion: its wood is quite affordable and at the same time has good technical characteristics.

Bars made of harder wood species (larch, oak) can rarely be found on free sale, and the price for them is incomparably higher, and pine wood after appropriate treatment with antiseptics will be little inferior in durability to the use of the same larch.

When buying a bar, you should choose a material with dry wood. Otherwise, after the installation of the beams, their deformation during the drying process is possible - bending and twisting.

Flooring

Wooden flooring laid on the joists will be a rough sub-base for the floor covering

Usually, the flooring of interfloor ceilings is performed in two tiers: from the bottom there are subfloors, on which the insulation is laid, and from above there is the prefinishing flooring, mounted on top of the load-bearing beams. A decorative floor covering is laid directly on it.

To determine the nature and amount of material for the flooring, you should clearly think over the structure of the floors.

In the construction of the subfloor, either 5 x 6 cm bars stuffed onto the supporting beams or grooves made in the beams can be used as a support for the floorboards. The latter option is quite time consuming, therefore, most often, 5 x 6 cm bars are used to create a support.

To calculate the required number of bars, it is enough to count the number of beams and multiply them by the length of each of them. The resulting footage (the total length of all beams) is multiplied by two more (since the bars will be packed on both sides of each beam).

A wide range of materials can be used for finishing flooring. This can be boardwalk, plywood, chipboard, MDF, OSB, etc. Each of these materials has its own advantages and disadvantages, after reading which you can opt for one of them. To calculate the required amount of material, it is enough to simply calculate the area of the room.

When purchasing building material, you should always purchase it with a margin of 10 - 15%, since unforeseen material overruns are inevitable during construction.

This will save you from having to interrupt work and buy the missing part.

Impregnation

Antiseptic will prolong the life of the tree

To maximize the service life of wooden structures, they must be treated with antiseptic materials.

It will also be useful to treat the wood with fire retardants, which increase its fire safety.

To calculate the required amount of impregnations, you should read the instructions for its use - there is always indicated the approximate consumption of the mixture per sq. M.

Waterproofing

Since wood is afraid of moisture, waterproofing materials are always used during construction.

It can be a roll-up waterproofing used to create a water-repellent layer between wooden floor structures and the topcoat, or between wood and brick (stone, cinder block, etc.).

To protect wood from dampness, you can also apply a coating waterproofing based on polymers or liquid bitumen.

Heat and sound insulation

If it is necessary to create a barrier to noise or cold, insulating materials are used in the construction of the floors. Most often, for these purposes, a minelite or foam is used. Their total number by area should be approximately equal to the area of the room. For more information about floor insulation, see this video:

Expanded clay or ordinary slag mixed with sawdust can also be used as an insulating material.

Fastening materials

For fastening wooden floor elements, you should purchase self-tapping screws, nails, steel corners, anchor bolts and other consumables. When purchasing screws and nails, you should pay attention to their length.

According to the standards, for a strong connection, the nail should be 2/3 longer than the thickness of the attached element (board, bar). For self-tapping screws and screws, this figure can be reduced to 50%.

Those. for reliable fastening to the beam of the "forty" board, you will need 120 mm nails or self-tapping screws 80 mm long.

After all the necessary materials have been purchased, and all preparation has been completed, you can proceed directly to construction work. The construction of interfloor floors can be divided into several main stages.

The part of the beam inserted into the wall is wrapped in three layers of waterproofing material

The installation of load-bearing beams is most often carried out at the stage of erection of the walls of the building. Before laying the load-bearing beams, their surface is treated with all the necessary impregnations.

Then their ends are cut at an angle of 60 ° and that part of them that will be walled up in the wall is wrapped in 2-3 layers of roll waterproofing.

The ends of the beams are usually also coated with waterproofing compounds, but some experts advise leaving them open to allow the moisture contained in the wood to escape freely.

The depth of placing the beams deep into the wall should be at least 15 cm. The pitch of the beams is usually taken at 0.6 m, but depending on the expected load on the floors, as well as on the thickness of the beam section, this indicator can be reduced or increased.

The choice of the spacing between the beams is also influenced by the technical indicators of the material used for the finished floor.

If the top flooring is supposed to be made of an inch board, plywood or chipboard, then the distance between the beams should not exceed half a meter, otherwise the floors will bend when walking. For more information on installing beams, see this video:

Overlap lags must lie in the same plane

The installation of the load-bearing beams starts from the two outer walls, while the beams should be located at a distance of 5 - 10 cm. After installing the two outer beams, we mount the rest, observing the required interval.

When laying beams, special attention should be paid to the horizontal slope: all floor beams must lie in the same plane. To do this, an edged board is placed on the edge between the two extreme beams, or the twine is pulled tightly.

If the base on which the beams are laid is uneven, then mortgages should be installed under the ends of the beams to level the horizontal level. For mortgages, material is used that is resistant to decay and physical stress - metal plates, pieces of tiles, etc.

It is not recommended to use wooden wedges to adjust the level of the beams, as they can rot quickly enough, which will cause the lowering of individual floor beams and the curvature of the floor line.

The load-bearing beams are attached to the wall using anchor bolts and steel corners.

Fastening support bars

After all the floor beams have been exposed, bars with a section of 5 x 6 cm (the so-called "cranial" bars) are attached to them. They serve as a support for laying the subfloor and are attached along the entire length of the support beam, on both sides.

They should be nailed in such a way that their lower part is flush with the lower part of the beams.

Most often, the subfloor is made from an inch board.

For the construction of the subfloor, edged boards are taken and laid across the beams on the support bars. Since the distance between the beams usually does not exceed 0.6 - 0.8 m, then an inch board or thirty is quite suitable for rough floors: the pressure on them will be limited only by the weight of the insulation.

Also, for these purposes, you can use a trim slab. You can also combine the sub-floors of the second floor with the finished ceilings of the first floor or basement. In this case, edged boards are hemmed from below, from the side of the first floor to the beams. For more information on the draft field, see this video:

Thermal insulation flooring

After the installation of subfloors, compartments are formed between the beams, which, if necessary, can be filled with heat-insulating materials.

To do this, a hydro or vapor barrier (roofing felt, isospan, etc.) is laid on top of the subfloor boards, and then mineral wool, polystyrene, slag with sawdust, etc. are laid.

In this case, the entire space between the bars should be tightly filled. Fill the gaps between the beams and the foam sheets with a sealant.

It is also advisable to lay a waterproofing on top of the insulation, which will protect it from moisture leaks from above.

The final stage will be the flooring of the final floors, which is attached over the load-bearing beams using self-tapping screws or nails.

For this, the material (boards, OSB, plywood) is cut in such a way that their joint is in the middle of the timber. The finishing floor is the basis for the topcoat - laminate, linoleum, parquet.

Wood has always been and will remain for a long time one of the most popular materials for arranging all kinds of power and load-bearing elements, roof frames, ceilings, partitions in an ordinary low-rise building. Instead of using expensive and very heavy concrete slabs or I-beams, it is possible to make a wooden floor between floors without the involvement of construction equipment, relatively quickly and at minimal cost.

Typical floor structure on girder supports

The arrangement of wooden floors between floors usually differs from the ceiling design in a number of parameters, primarily in the way the timber beams are laid and in thickness. If, when arranging the ceiling, wooden load-bearing elements most often rest on walls or a specially formed concrete belt, then the overlap between the floors has to be cut into the walls of the box. Accordingly, the requirements for the strength of the beams and the thickness of the floor between floors are much more stringent than for the ceiling.

Structurally, a wooden floor is assembled from the following parts:

Supporting wooden beams that carry the weight of all structural elements, the mass of furniture, household appliances, people - everything that is on the floor above;
Plywood or OSB boarding of the ceiling surface;
System of lags with floor boards of the upper floor;
Mats or thermal insulation boards laid on a wooden crate;
A film of waterproofing against moisture leaks from the floor on the floor above and a vapor barrier is required to prevent the penetration of water vapor into the elements of the wooden floor from the lower floor.

The structure of the wooden floor between the floors is very similar to the roofing cake of a conventional gable roof, but there is one peculiarity. If the rafters have at least one attachment point on the hinge, then wooden floor beams between floors most often have to be laid according to a freely sliding pattern, without fixing at the support points. Provided that the distance between the walls is no more than 3 m.

Such schemes are used in houses with brick and concrete walls, where the rigidity of the box allows the use of self-aligning wooden floors. What does it do? Regardless of the settlement of the building and the pressure on the floor of the upper floor, the floor plane will remain in the same position.

If the length of the wooden floor beams exceeds 4.5 m, or the walls of the house are made of weak materials, for example, aerated concrete blocks, foam concrete, wood concrete, the load-bearing floors between the floors must be reinforced with additional corners, anchors, struts and pin fittings.

Varieties of structures and materials of wooden floors

The main element of the floor between the floors is the load-bearing beams. The strength of the overlap and the safety of the owners themselves depend on how correctly the materials for making a wooden "pie" between floors are selected. The thickness of the cake is always limited, so you have to either increase the number of load-bearing elements or change the material.

Traditionally, the following materials are used as load-bearing elements:

Glued laminated timber;
Sawed log;
A package of sanded and knocked down boards.

It is clear that the best option will be the most expensive. The use of glued beams for the overlap between the floors allows you to make the wooden frame as rigid as possible, therefore, they resort to timber tightening either at the request of the owners, or with very large sizes of the upper floor rooms. Most often, glued laminated timber is placed in a wooden floor with a distance between the walls of 4 m. It turns out to be expensive, but reliable.

A more economical way is to use coniferous lumber, usually a pine debarked log is cut with disc cutters into a two-edged or three-edged beam. Such a beam turns out to be stronger and cheaper than a regular wooden rectangular bar.

The most budgetary option is a package beam. It is knocked down from a calibrated and polished forty board, two or three per one beam. Before assembly, the wooden surface is treated with impregnation, dried and painted over with linseed oil. The overlap of the stacked timber is considered the most flexible and at the same time the most reliable.

Even if an overload occurs, the wooden elements will bend, but there will be no break or collapse between floors. It is much easier and cheaper to assemble such a wooden floor between floors with your own hands, since there is no need to purchase timber or glued beams.

To reduce the complexity of the work and the size of the costs, taking into account the design of the house and the width of the walls, several design options are made, depending on how it is planned to lay the floor of the second floor on wooden beams:

Light overlap. For frame houses, the pitch between the supporting elements can be reduced to 30 cm, and the joists under the wooden floor are not laid. The structure itself is assembled without insulation and film insulation;
Medium floors on the floors. In the design, logs and sound insulation are used, a vapor barrier film and insulation are not used;
Warm medium hardwood floors. A full-fledged package with insulation and film hydro and vapor barrier is laid between the floors.

Light floors on floors are used for unheated buildings, medium-sized systems are used for buildings with powerful external wall insulation. Warm wooden structures are used if the upper floor is bordered by an attic or attic.

It is known from practice that sheet and fiber materials provide the best sound insulation between floors for timber structures. You can use mineral wool or loose expanded clay granulate. But both materials are highly absorbent, so you have to install a vapor barrier film. Expanded polystyrene is not afraid of moisture, but sound insulation on the floor is about 3-4 times worse than mineral one. Therefore, EPS or foam is used where the sound insulation of the wooden floor between floors is not particularly important. For example, between the basement and first floors.

Methods for embedding load-bearing elements

In order for the wooden flooring on the floors to turn out to be reliable and stable, it is necessary to choose the right way to embed the load-bearing beam into the walls of the house. The fastening system is chosen depending on the material of the walls.

The easiest way is to fix the timber to the brick walls. For each support, a niche is cut out according to the markings in the wall, with a depth of at least 100 mm and dimensions 15-20 mm larger than the cross-section of the bar. A lining made of hard rubber is placed in the niche, and the ends of the timber must be covered with liquid rubber or hot resin before assembling the wooden frame. If the timber is more than 4.5 m, one end is fixed with a through metal stud. The remaining space of the niche is blown out with polyurethane foam so that there is no draft in the cracks on the floors.

The fastening of supports on aerated concrete walls turns out to be more difficult. Before making a wooden floor between floors, you will need to build a load-bearing box, into which the timber is laid. For a two-storey aerated concrete building, with brick wall cladding, it is allowed to lay a wooden box, in other cases, the support box must be cast from reinforced concrete.

If the timber is planned to be cut into wooden walls, then this is best done at the stage of laying the crowns. As in the case of brick walls, a niche in the form of a truncated dovetail wedge is cut out in the wall beam according to the markings. The end of the supporting beam is adjusted to the shape of the lock and placed in a niche. After laying the beams, the docking place is reinforced with metal plates and corners.

Do-it-yourself flooring on the floors

After the required height of the walls has been reached to the level of the next floor, it is necessary to make the overlap. The next row of brick or block is laid out with niches for a bar. To ensure the necessary strength of the wooden frame, you need to make a verification calculation or select the cross-section of the timber according to reference tables and nomograms.

Roughly, for a two-meter span, it will be sufficient to use a timber support with a section of 75x150 mm, for a five-meter section of a beam, it should be at least 150x225 mm. The standard pitch is 80-90 cm, but sometimes it is deliberately reduced in order to increase the rigidity of the lower floor box.

Laying load-bearing elements of a wooden span

At the time of assembly of the span frame on the floor, the wooden beams must be completely ready for use, but without applying resin to the support ends. With a beam length of 3-4 m, it is difficult to accurately guess the length of the beam, therefore, wooden blanks are raised to the level of the upper floor and successively adjusted according to the linear dimensions of the landing nests.

If the measurement of the distance between the niches corresponds to the length of the workpiece, proceed to assembly:

Both ends are cut at an angle of 60 ° in order to facilitate the laying of the supporting ends in niches, and are treated with tar or bitumen mastic;
Lining material is laid in the niches, after which the beams of the wooden floor are installed.

Each beam must be carefully adjusted horizontally and along the general plane; for this, the linings are replaced with thicker dies or cut them to lower the end. The remaining space is clogged with tarred tow and blown out with foam.

For your information! To simplify the work, initially two extreme beams of a wooden span are laid and exposed, and the remaining workpieces are adjusted along them with the help of cords or a laser level.

Build the battens

After the timber support beams have been laid and fixed in the niches, the cranial block must be filled. In fact, this is a long rail, with a cross section of at least 40x40 mm, the cranial rail is stuffed onto the lateral surfaces of the timber flush with the lower edge. The lower padding with sheets of plywood or OSB will be attached to the cranial strip. Nailing the plywood directly to the timber can weaken the structural beam. In addition, when walking on the floor of the upper floor, nails and fasteners driven into the wooden beam of the floor come out of the body of the wood, therefore it is necessary to strengthen the fastening of the padding.

At the same time, a vapor barrier film is sewn under the plywood, each new sheet of film must be glued with construction tape, otherwise the condensate will rot the wooden floors on the second floor. If the upper floor is unheated, then it is necessary to make air vents in the floor structure to remove part of the condensate that has got inside.

After the padding has been laid, you can proceed to insulation and sound insulation. Often, instead of mineral wool or slab polystyrene foam, a special filler made of polystyrene granules is poured into niches. In order to create a zone of silence on the floor, it is enough to fill in a layer with a thickness of only 40 mm into the ceiling. That is, the interfloor overlap can be reduced by almost 50-60 mm.

Final operations

This is followed by the laying of waterproofing, the film must be installed without fail if the higher floor is intended for living or there is no floor ventilation system in it. Even if the hardwood floors are not flooded with water, when ventilated, the colder air will collect condensation inside the hardwood floor. You can cover with ordinary plastic wrap with a thickness of 0.2 mm.

All other floor details depend on the method of flooring on the upper floor. If you plan to lay laminate or parquet flooring, it is best to put a layer of OSB or moisture-resistant drywall. If an ordinary wooden floor is planned on the second floor, then it will be enough to fill the logs and sew up the surface with a tongue-and-groove board.

Conclusion

In special cases, a cement-sand screed can be provided in the floor structure. For this, two layers of fiberglass reinforcing mesh are laid on top of the insulation and waterproofing. The thickness of the screed must be no more than 50 mm. Under such a base on a wooden floor, you can lay bulk or decorative 3D coatings.