Lag splicing. How to correctly calculate the distance between floor joists? Linear dimensions of wooden beams

Wooden logs are one of the most popular building materials, most often used in individual construction, therefore it is important to maintain the correct distance between the logs of a private house.

Logs are wooden beams that serve as the basis for fastening subfloor elements (boards, plywood sheets, chipboard, etc.). As a rule, timber obtained from coniferous species wood (pine, spruce, fir, larch).

As a rule, before installing logs, they are additionally treated with antiseptic and fireproof impregnation.

LOG SELECTION PARAMETERS

The moisture content of the wood at the time of application of the logs should not exceed 18-20%. For the logs, choose a rectangular beam with a cross-sectional aspect ratio of 1.5-2. The shorter side of the beam section is installed in the direction of application of the static load.

If you do not have timber of the required cross-section, then it is permissible to use stacked logs from boards or timber of a smaller cross-section than the design one. In this case, a magnifying factor of 1.2 is applied. In order to ensure the evenness of the finished floor, it is necessary to install the base logs at a level.

Floor joists solve several problems:

LOG INSTALLATION OPTIONS

Most often, there are three options for installing logs as bases for flooring.

Base for subfloor

The joists can be used as a base for installing a subfloor and are mounted on an existing floor.

In this case, as a rule, the logs are fixed to concrete floors, on either earthen floor and their main function is to keep the rough and finishing floors from deformation and destruction.

Joists on poles

Logs can be installed on support pillars, mounted in the underground of the house. In this case, the logs transfer the load to these foundation elements. The purpose of the joists is to withstand the load acting on the floor covering and redistribute it to the supporting pillars.

Logs – interfloor covering

Logs can play the role of not only the basis for the floor, but also be an element interfloor covering and bear the static and dynamic load, redistributing it to other floor elements.

It is clear that the most insignificant requirements for the strength properties of the logs are imposed in the first case. The thickness of the timber for the logs is taken to be of the minimum cross-section. In this case, they are often guided by the thickness of the heat-insulating layer located between the joists rather than by calculating the strength.

The distance between the lags is selected based on the minimum sagging of the subfloor elements, be it boards or plywood. Recommended distance is 0.5-0.7 m. It is possible to create a box-shaped structure from logs by connecting them in perpendicular directions in the plane of the floor.

In the third option for using lags, an accurate calculation of the cross-section and distance between the lags is required. And in the second option, it is necessary to calculate the cross-section of the beam, since the distance is determined by the gap between the support pillars.

There are several ways to correctly calculate these parameters: using construction tables, using special construction programs or by contacting a design specialist. Let's try to do this calculation ourselves.

CALCULATION OF LAYER PARAMETERS FOR FLOORS

For correct calculation, you need to understand what other characteristics the strength of a given structure depends on and these are:

So, here's an example of a calculation.

You have chosen a board for rough flooring with standard thickness 2.4 cm, the width of your room is 3 m. Length – 11 m. Using two basic tables, the cross-section of the timber and the distance between the logs are selected. For a board thickness of 2.4 cm, the distance between the logs should be 40 cm. For a span width of 3 meters and a design load of 300 kg/sq.m. We recommend timber with a cross section of 15*8cm.

Another feature of the calculation is that it is necessary to take into account the minimum distance between the supporting wall and the outer beam; from practice it is 3 cm. The number of lags is calculated using the formula:

DP=RL*(CHL-1)+TL*CHL+KB*2, Where

• DP– length of the room, for our example – 11m=1100cm.
• RL– distance between the logs (from the table) – 40 cm.
• TL– log thickness (from the table) – 15 cm.
• KB– the distance from the outer joist to the wall is 3 cm.
• CL– number of lags – determined number.

Substituting the values ​​into the formula, we get:

1100=40*(CHL-1)+15*CHL+3*2

1100=55*CHL-CHL-34

CHL=1134/55=20.62 rounding to 21 pieces

Now let's calculate the distance between the lags:

1100=RL*(21-1)+15*21+3*2

1100-6-315=20*RL, RL=38.95 cm.

Using the above method, you can quickly calculate the distance between the joists and their number for the subfloor in a private house.

Increasingly, owners are trying to furnish their apartment, dacha or Vacation home. This choice is justified, because it allows you to save money. financial resources and produce renovation work as far as possible. One of the important construction processes is the installation of lag. But here many questions arise: how to choose the right material, at what distance the floor joists are laid and what are the installation rules.

What are lags?

The structure, which consists of transverse beams and serves as the basis for the flooring, is logs. Bars or beams can be used for such a design, with self-installation Most often, wood is used, but materials such as metal, reinforced concrete, and polymer are widely used in construction. By installing logs, you can take advantage of the following advantages:

• Increase the level of sound insulation;
• Increase the level of thermal insulation;
• Correctly distribute the load;
• The presence of underground ventilation is especially important if laying engineering communications;
• Ideally flat floor surface;
• Strength and resistance to external loads;
• If necessary, it is possible to replace individual element designs.

Materials such as wood are valued for their naturalness, environmental friendliness, and beautiful appearance.

Choosing material for logs

The quality and strength of the structure will depend on the choice of material; if you follow some rules, the logs will ensure reliable and durable operation.

• Relatively cheap types of wood are suitable for the structure. It could be fir, pine, great option spruce. You can use larch, but such material will be more expensive.
• For the structure, 2 grades of wood are suitable, you should not refuse 3, the moisture content of the material is important, it should be up to 20%, but not less than 18.
• You need to pay attention to the cross-section perfect option, when the height dimensions are 1.5-2 times the width of the beam, in other words, the section should have a rectangular shape.
• Also, the size will depend on the insulation, namely its thickness.
• The span of the room is taken into account.

This table shows the section dimensions for different spans, provided that the step corresponds to 70 cm.

Span dimensions	Section size

If the span size has an inaccurate value (intermediate), you should take an approximate option, but take into account the safety margin.

Choosing a decking material

The type of wood must be selected taking into account the characteristics of the room. Of course, the financial side is also important, premium the material will cost much more, but if the floor will be covered, for example, with paint, then it is better to choose the second grade. If provided varnish coating, then the first grade is needed here. When the floor is laid in utility rooms, preference can be given to the 3rd floor. Which breed is better to choose:

• Fir, pine and spruce are soft species. Such a coating will not be practical or durable, since even heels leave marks on such a surface. Such flooring is possible if the room has low traffic and if it is treated very carefully.
• To the very durable material oak is used, but such flooring will be expensive. It can be used in any room.
• Another species is highly durable - this is Siberian larch, it has the peculiarity that the wood contains resins that protect it from rotting, so this flooring is often used in bathhouses.
• And for arranging children's premises, alder or aspen is ideal.

When choosing, you need to pay attention to the moisture content of the wood. If you use damp material, then after some time the flooring will dry out and cracks will begin to appear. But overdried material can create cracks. The ideal humidity is 12%. You need to carefully inspect the material and do not use defective boards. You need to purchase material with a 15% reserve.

The wood is of very high quality and durable material, but in order for it to justify itself in operation, it needs to be processed. Now you can purchase various antiseptics that will protect wood from rotting, fungi, mold and beetles.

How to calculate distance

The pitch of the lag will depend on which flooring is chosen. Here you should use the following rule: if the flooring is thin, the logs should be placed with minimum distance. When the coating is thick and durable, logs are placed relatively rarely.

In order to find out the exact distance data, it will be necessary to carry out the following calculations.

For example, there is a room 11m long, the joists are 0.15m wide, and the flooring is 25mm thick. If you follow the table, then the distance between the logs should be from 40 to 50cm, you should take the average value, which corresponds to 45cm.

While the total number of lags is unknown, it is denoted by – x, respectively the width total number lag is 0.15x. Since the first joists are laid at a distance of 30mm from the wall, the value will be as follows: x-1, to indicate the total distance - 0.45 (x-1).

Having such data, you can create an equation that looks like this:

11(room data) = 0.15x (lag data) + 0.45(x-1) (lag step) + 0.06(distance from the wall).

You need to find out x in this case it is equal to 18.9, this value must be rounded to 19 - this is the number of lags. Next you need to find the sum of all distances. For this, 11-0.06-19x0.15 turns out to be 8.09 m. Then we divide the amount by the quantity, it turns out 44.94 cm - this is the exact distance that should be between the logs.

Such accurate calculations are used quite rarely and they are not at all necessary; you can use these tables. If, when installing the log at the final stage, the distance does not coincide slightly, there is nothing wrong with that, you can take a smaller step, thereby making the structure stronger.

Conclusion

As you can see, when laying a floor, each stage is important. Therefore, it is necessary to pay attention to each process, but if you take into account all the recommendations and follow the rules, then laying the floor will not bring difficulties, and the result will be reliable and durable.

Wooden construction materials, combining high strength, environmental friendliness and ease of installation, are widely used in modern low-rise construction for the construction of roofs, floors and power frame floor. Correctly calculated distance between floor joists and interfloor beams is the key to strength and durability not only of the individual structural element, but also the entire structure as a whole.

What are floor joists?

Floor joists made of wooden beam of a certain, precisely calculated cross-section, they are force elements that absorb static loads from furniture and equipment installed on the floor and dynamic loads that arise when people move indoors. Floors on wooden logs have some features that make it possible to mitigate minor shortcomings of building structures:

• Uniform distribution of load on underlying building structures;
• Increasing the overall strength of the floor or ceiling;
• Improving sound insulation properties with the formation of an additional heat-insulating layer;
• Possibility of laying utilities while ensuring relatively high maintainability;
• Low complexity of installation, providing flat surface for the installation of floors made of sheet or roll materials and flooring from natural wood valuable species.

Logs are made mainly from coniferous wood, the resin content of which provides protection from moisture and a long service life. To install logs in difficult-to-use rooms, they are used hardwoods with high moisture resistance or larch products with a high content of natural resins.

Why is it necessary to calculate the distance between lags?

Like any other construction materials, wooden crafts have certain indicators of strength, wear resistance, service life and, of course, prices. When installing wooden floors along joists or interfloor beam floors You can also use thick logs laid at close distances from each other, obtaining the highest structural strength and spending a fairly significant amount. But use required quantity logs or beams having a cross-section corresponding to the expected load will allow obtaining the necessary structural strength at significantly lower costs.

IN panel house When the logs are laid on the surface of a reinforced concrete floor slab, their cross-section is chosen to be the minimum required for attaching a floorboard or chipboard. Another thing is application. wooden structures V frame structure, when the logs serve not only as the basis for the future floor, but also serve as a strength element of the frame connected to the wall supports.

Main calculation criteria

• Thickness of the floorboard or board materials OSB, chipboard;
• Number of support points or distance between walls;

Having even such minimal data, you can correctly calculate the required cross-section of a wooden beam for making lags and the maximum step between lags.

Beam section

The cross-section of the wooden beam for installing the logs is selected depending on the distance between the supports and the required load-bearing capacity of the floor. When calculating the required cross-section of the joist, you should take the maximum load on the floor to be no more than 300 kg per m2.

A square or square beam is used as a log rectangular section, the wider side of which is located vertically. This way, the maximum rigidity of the log is obtained at minimum consumption wood, which reduces unproductive costs for flooring. In construction practice, the ratio of the beam width to its height is 1.5-2, which is optimal from the point of view of strength and cost. When used as a standard log edged boards 5 cm thick, its height with a gap between supports of 2 m should be from 10 to 15 cm. Standard sizes The log depending on the span is presented in the table:

Sometimes it is difficult for an individual developer to find a standard timber suitable for making logs of the required section. The way out of this situation is quite simple. To ensure the required load-bearing capacity of the floor, you can install several standard boards 5-6 cm thick side by side, increasing the height of the resulting beam by 1-2 cm relative to the standard one. Such " layered cake", even in the absence of fastening the boards together, completely replaces solid timber of the required dimensions. Similar results can be achieved if the boards are placed at regular intervals along the entire length of the supporting surface of the foundation.

The only thing to consider is frame house This method of load distribution is quite difficult to apply due to the connection of the logs to the racks of wall structures, openings and the distribution of insulation. In a frame house, floor joists are used as interfloor beams, so the minimum required cross-section must be increased taking into account the load from ceiling structures and insulation.

Step between joists

When making wooden floors, it is clearly visible how the distance between the joists, called the step, depends on the thickness, and the type of materials used. The thicker the board used as flooring, the greater the distance between the joists. More clearly about which step you need to choose when using different thicknesses boards, the table below shows.

As a rough draft flooring V modern construction very often slab construction materials are used instead of boards, which accordingly changes the calculation method. Chipboard (chipboard), cement bonded particle board(DSP), oriented strand board (OSB) and gypsum fiber boards (GFP) are successfully used as a base for coverings made of rolled materials or ceramic tiles, arranged according to wooden joists. In some cases, chipboard may be additionally coated with materials based on cement or gypsum base. Considering the greater bending rigidity of chipboard and lower strength than boards, you should choose a pitch between lags of no more than 40 cm, and when using thicker chipboard (20-22 mm), increase the pitch between lags to a maximum of 60 cm.

When calculating the step between lags for a specific room, you can use the average table values, and if the distance between the last lags is smaller, then the strength of the floor in this place will only increase.

Consequences of errors in calculation

What happens if you choose the wrong section of the lag and the step between them? When installing floors concrete base most important parameter there will be a step between the lags, on which the behavior depends finishing coating. Chipboard board, fixed on logs installed with a larger gap than allowed, may sag or break, ceramic tile- crack, and the board - bend. In any case, the floors will require redoing.

More unpleasant consequences occur from errors in calculating the required number of logs used as interfloor coverings. If it should be used large quantity lag or a larger cross-section than indicated in erroneous calculations, the strength of the entire structure is significantly reduced, which can lead to irreversible deformations and complete destruction of the floors.

Calculation methods

To calculate the size of the timber and the number of elements required for installing a wooden floor on joists with rough coverings made of boards or chipboards, you can:

• Contact design organization, which is on professional level will calculate how many elements there should be for a covering made of boards or chipboards, and what size of timber should be used during construction;
• Use special average tables yourself, choosing which value is closer to the required one, leaning towards big side, if there is no exact match between real and tabular sizes;
• Use computer programs and online calculators into which you enter enough a large number of parameters, and the program will accurately determine required dimensions timber and the distance through which it must be installed.

Logs are lathing elements for flooring. They are necessary for the final floor structure to be of high quality: smooth and strong. Strengthening and leveling the floor surface without joists is very problematic. An unreinforced covering will sag under the influence of heavy furniture, and the floor itself will creak and vibrate when walked on it. Floor joists are almost always installed. How is their size selected and installation done?

Why is laying joists so important?

The main function of the log is to create a flat surface for next works. But sheathing under the deck also serves other purposes. They promote complete ventilation of the underside of the flooring, which prevents the boards from rotting.

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This timber base feature has great importance in those rooms where the floor is laid on the ground and dampness due to groundwater creates serious problems even with a high underground floor.

With the help of joists, a space is formed between the flooring itself and the base of the floor - a kind of buffer that helps improve the soundproofing qualities of the floor. The same space is used for laying a layer of insulation, and, if necessary, utilities.

Installing floor joists allows you to obtain a durable floor even with an uneven base due to support points placed at a certain pitch.

Lathing materials

As a base for the flooring, you can use any materials that meet the requirements of strength, evenness and low deformation coefficient under load. These specifications correspond to products made of metal, plastic, reinforced concrete, wood and compounds made on the basis of synthetic resins. What kind of joists are best to use for the floor? Comparing the cost of all the above materials allows us to identify the favorite - wood. In practice, ordinary wooden beams are used for logs.

The material for timber is usually coniferous wood. The timber used for floor joists is made from spruce, pine, and fir. But larch is recognized as the best option, since its wood is not only highly durable, but also resistant to rotting.

Spruce and pine are more popular only due to their low cost.

When choosing a material, you can ignore the availability resin pockets and other minor defects and buy grade 2 or 3 lumber - the functionality of the timber base will not suffer from this.

Beam made from Siberian larch.

When choosing logs, you can save on material by replacing larch with spruce, but saving on the moisture content of the beams is not recommended in any case. The moisture content of the timber should not be more than 20%; at higher humidity values, the material will be deformed during the drying process, which will lead to problems with the finished floor.

If you have chosen spruce or pine as the material for the sheathing, then you should take care of waterproofing the beams when laying them. The joists can be laid on different floors; depending on the characteristics of the base, the waterproofing work will also differ. If the bars are mounted on reinforced concrete slabs floors, you first need to lay a layer of foamed polyethylene. In the case when the logs are attached to brick columns, polyethylene is laid between the soil and the column itself, as well as between the column and the beam. For the layer between brick and wood, roofing felt is suitable instead of polyethylene.

Foamed polypropylene.

Floor joists, regardless of the type of wood, are recommended to be treated with an antiseptic before installation. Such precautions are most relevant in wooden private houses, where woodworms can become a problem for the owner of the house. big problem, as they pose a threat to the durability of the entire structure.

Determining the dimensions

The reliability of the entire floor structure depends on how correctly the size of the lag is selected. Before purchasing beams, you should calculate their required length and thickness.

There are usually no problems with the length of the lag: depending on the direction of installation, it should be equal to the length or width of the room where the floor is being made. The best option is the length of the timber 2.5-3 cm less than this distance. This ratio of two values, when the length of the log is slightly less than the length of the room, allows you to avoid deformation of the structure due to temperature changes.

The length of the beam should be 2-3 cm shorter than the width of the room.

It is advisable to make floor joists from whole lumber, but this is only possible when the size of the timber matches the parameters of the room. If the length of the bar is not enough, then splicing two elements is used. The work is carried out in half a tree, sometimes using galvanized overlays.

It is not difficult to splice two bars, but in order for the structure to be strong, two rules must be strictly followed:

• There must be some kind of support under the splice area, the best option there will be a support column;
• If two adjacent logs are spliced, then their splice points should be offset relative to each other.

Failure to comply with these requirements entails the risk of low floor rigidity at the junction of the timber.

Methods for splicing lags.

Adjacent floor joists should be spliced ​​with an offset of one meter. This parameter affects the size of the original bars, which should also be taken into account when purchasing them.

If everything is quite simple with the length of the beam, then determining the parameters of the lag section is more difficult. What it is? The cross-section of the log is its thickness, which depends both on the material of the beam and on the design characteristics of the future floor.

The cross-section of the joists for the flooring is calculated based on the maximum possible load on the floor and the size of the spans between the support points of the beams. Commonly accepted meaning maximum load is a level of 300 kg/m2 - this parameter is applicable to residential premises.

When determining the size of the joists based on this load level, the length of the span between adjacent beams is taken into account. How are the distance between floor joists and their thickness related? For this, there is a special table of sizes used by specialists. In the most common cases, the correspondence looks like this: with a span length of 2 m, a beam of 110x60 mm is used, with a span length of 3 m - 150x80 mm, with a span length of 4 m - 180x100 mm. How larger size span, the thicker should be the timber from which the logs are made.

The cross-section of the timber is usually rectangular. In order for the logs to withstand pressure, the rectangular beam is laid “on edge”. This feature of installing the base for the future floor provides maximum level timber rigidity with a minimum volume of lumber.

The thickness of the joists used for flooring may be greater than the specified parameters. Installing logs from timber of greater thickness is not prohibited, and sometimes it is simply necessary.

Sometimes increasing the cross-sectional dimensions of the timber is necessary to lay a thick layer of insulation.

When choosing joists for a new floor, you should also take into account that if you are going to install the floor in non-residential premises, then the load on the structure can exceed 300 kg/m2. This parameter will have to be calculated by calculation, and then, based on the data obtained, select lags with suitable parameters sections.

The size of a metal beam may be smaller than a wooden one.

If you decide to use metal or reinforced concrete beams instead of wooden beams, their thickness may be less. This is explained by the fact that they have a higher resistance to deflection compared to wood.

How to determine the step?

The size of the joists is determined by the size of the span between them, which in turn depends on the thickness of the board used to lay the wooden floor. Here you should be guided by the following rule: the thicker the flooring, the larger the step you can take. There is a completely logical explanation for this, because the thicker the board, the less susceptible it is to sagging under the influence of gravity.

The ratios are as follows: with a board thickness of 2 cm, you can take steps up to 30 cm, with a thickness of 2.5 cm - up to 40 cm, with a thickness of 3 cm - up to 50 cm. In order to calculate the possible span length for a larger board thickness, you can use the formula: increasing the thickness of the flooring board by 0.5 cm increases the possible length of the joist step by 10 cm.

If plywood or OSB is used instead of flooring boards, then the calculations are slightly modified. These materials are more rigid in bending, so their thickness is smaller. With a material thickness of 1.5-1.8 cm, you can plan a lag pitch within 40 cm, with a thickness of 2.2-2.4 cm - within 60 cm.

When using plywood or OSB, sheets of material must be attached to the joists in three places. Floor joists should be positioned so that the fastenings are at the edges of the sheet and in the middle. In this case, the edge of the sheet is not laid across the entire width of the beam, but only up to half.

Laying joists on the base

Wooden logs can be attached to any base, the main thing is to follow the installation rules. To carry out the work of laying sheathing from logs, you will need the beams themselves, a jigsaw, a level, a screwdriver and fasteners. A jigsaw can be replaced with a hand saw.

Attaching the joists to concrete floor implies the use various designs, which are divided into simple and adjustable. Adjustable elements have screws in their design, with which you can align the logs.

Special anchors or screws are usually used as fastening. Theoretically, it is possible not to secure the joist bars at all, but then there is a risk of destruction of the floor structure due to the joist moving to the side.

In addition to the tools listed above, you may need additional devices. Do-it-yourself installation of floor joists on concrete or soil requires additional fixation using a manual hammer drill.

Adjustable logs.

Laying the logs on the ground is done as follows. First, the support pillars are installed. To do this, dig holes about 10 cm deep, fill them with sand and spill them with water for good shrinkage. A plastic film is laid on the sand, on top of which a brick column is erected on the mortar. Its length and width are usually equal to the edge of the brick. The finished columns are covered with roofing felt. Timber is laid on them without fixation, then the logs are hemmed to the walls with galvanized corners.

How to lay logs for the future floor if the base is wooden beams? The order of work depends on how the timber is laid on the beams: across them or along them. If the beam is placed across the beams, then the logs are attached to the beams with ordinary self-tapping screws of suitable length.

In this case, it is important not only to treat the logs with an antiseptic, but also to drill holes, otherwise the risk of the beam splitting will be very high.

If you decide to attach the beams along the beams, then to compensate for the difference in their height, the logs can be attached not only on top, but also hemmed on the sides. Having completed all the work correctly, you will be able to level the floor with least loss room height.

Attaching the joists to the concrete floor is done as follows. If you are carrying out floor installation work on the ground floor of a building, then the ceiling should be waterproofed plastic film. You can use foamed polyethylene with a foil layer. This material will provide not only waterproofing of wood, but also reduce heat loss during further exploitation premises.

The beam is laid out in accordance with the previously determined lag pitch and set according to the level. To level the base for flooring, pads made of plywood and the bars themselves are used. After this, the logs are fixed to the floor. The best option is the use of anchors mounted under a screwdriver. There are also alternative way laying timber on a concrete floor using stands. The stands are attached to the floor slab, and the logs themselves are attached to them with self-tapping screws.

When preparing to install the floor, it is important to correctly calculate the length and cross-section of the joists, and also think about what distance will need to be laid between the floor joists. If all parameters are determined correctly, then when using quality timber and responsible implementation of all work on its installation, your floor will be smooth and beautiful, and will not sag under the weight of furniture or creak when walking.

When I determined the distance between the columns for the logs, I was guided by some article from the Internet. The same article recommended taking into account the option of laying insulation between the joists. After all, with a floorboard thickness of 35 mm and the expected width of the carpet mineral wool 60 cm (120/2). The distance between the lags was chosen to be 58 cm (2 cm for cotton wool compression). Considering that the log itself has a width of 7.5 cm, the distance between the axes or centers of the columns was 65.5 cm. In older paper publications, these distances are slightly different and I have not seen a clear calculation anywhere.

After preparation, brick columns are laid out of lean concrete with a pitch (along the axes) of 0.7...0.9 m and with a distance between rows of 100...120 cm. Two layers of roofing material or roofing felt and an antiseptic wooden lining 3 cm thick are laid on top of the columns (Fig. 7.24). The logs are supported on them, and a plank floor is laid on top of the logs.

Rice. 7.24. Cold floor with warm underground
1 - base; 2 - waterproofing made of two layers of roofing material; 3 - lower trim;
4 - top harness; 5 - external cladding tongue and groove boards;
6 - non-ferrous metal plate with holes; 7-outer wall made of boards;
8 - plaster; 9- plinth; 10 - plank floor; 11 -lag; 12 - brick column;
13 - antiseptic wooden lining; 14 - underground

HA. Stern. Carpentry work. Stroyizdat 1992

Under the logs resting on brick pillars, to ensure waterproofing, you need to place scraps of roofing material, which also protects the wood from mold.

Plank floors laid directly on the beams if their pitch is relatively small. In case of sparsely located beams, additional logs are laid on them with the right step, and a plank floor is already laid on them. The logs are placed at a distance between the axes of 800-850 mm for boards with a thickness of 35-40 mm. With thicker boards, the lag pitch can be increased to 1 m, with thinner ones - reduced to 500-600 mm. The humidity of the boards should not be higher than 12%.

A wooden floor must have a zero slope, so beams and joists must be constantly checked using a level or level along and across the room. The pitch of the columns depends on the thickness of the logs - with a thickness of 40 mm - up to 900, with 50 - up to 1100, with 60 - 1200-1300 mm. The pitch of the posts in the transverse direction depends on the thickness of the floorboard.

Construction of a house from foundation to roof

The maximum distance between rows is selected from the cross section of the log. I used the Calculator to calculate the load-bearing capacity of single-span wooden beams" → (download). For a 150x75 log, it turned out to be more than 2.5 meters, but the width of the entire room is 6.2 meters. Hence the distance along the rows is about 2 meters

In general, of course, longer distances can be taken, but then there is a greater likelihood of all kinds of deflections and creaks occurring. Much depends on what will subsequently stand on this floor, whether the future residents will put some kind of piano or a tub with a palm tree and whether the floor will become curved or creaky.