At what distance are floor joists laid? Floor joists: arrangement of wooden support

One of the important issues in building a house is laying the floor. Modern tendencies in interior design bring us back to using natural materials. Wood is the most environmentally friendly and practical of them. This coating adds not only comfort and aesthetics. It is durable, highly durable, and retains heat well.

This floor is ideal for both a summer house and country house, and for a city apartment. Renew paint or varnish coating maybe once every 4-5 years. The tree will serve you for many decades. However, it is necessary to seriously approach the issue of preparing the base for its installation. Among the many methods, laying on logs is considered the most proven.

What are lags for?

Floor joists are floors made of wood, metal, plastic or reinforced concrete. As a rule, they have the form of beams that are laid across the future finishing coating. This is a kind of lathing that serves as the base of the floor.

Most often they are made of wood in the form of bars of certain parameters. It is more accessible, cheaper and is not inferior in quality to other materials. This method of installation is used to securely secure the floor to avoid sagging under heavy furniture, so that it does not vibrate or creak. According to statistics, it is used in 90% of cases.

The main advantages of the log:

noise absorption;
floor ventilation;
increase in thermal conductivity;
the ability to use empty space for various utilities;
floor leveling;
increasing the strength of the coating up to several tons per square meter;
ease of installation and replacement;
low cost.

The material for logs is most often pine, spruce or fir. Larch is more expensive, so it is not so popular. Since they serve as a base for the floorboard, grades 2 or 3 are quite suitable. They may not be as neat as grade 1. The presence of knots and smudges of resin will not affect the reliability of the structure.

Typically, wood is stored in certain conditions. The humidity of the material ready for use should be about 15-20%, but no more. Before starting work, the wood must be treated with special impregnations.

They are harmless to human health and often require simple dilution with water in certain proportions. This prevents the appearance of fungus and mold on the tree, protects against bugs and rodents. The procedure is quite simple, but requires reapplication after 3 or 5 hours.

Floor joists perform many useful functions. It is worth keeping in mind that incorrect installation can lead to dire consequences in the future. The shape of the beam must be rectangular.

They best withstand heavy loads in a ratio where the height is one and a half or two times greater than the width. The beam is always placed only on the edge. The table shows the size of the lag section for certain spans. The step between them is in this case is 70 cm:

The size of the section depends on the strength of the material used and the expected load on the floor. For residential premises it is established that it does not exceed 300 kg per m2. These values are recognized by experts. However, they can be made thicker depending on the situation. For example, it is necessary to increase the space for thick insulation. Or an increased load on the coating is expected. How stronger material, the smaller its size can be. This applies, for example, to iron.

The length of the logs must correspond to the length (width) of the room minus 2.5-3 cm. This margin is necessary to maintain the strength of the structure in case of fluctuations in temperature and humidity. It is recommended to use long logs. It’s good if their size matches the length of the room.

If it is necessary to join them, then the joints should be shifted relative to the neighboring ones by about half a meter, or better yet, by a meter. A support is made at the splice site. It is usually done in column form. Splicing occurs using galvanized plates, but more often - half-tree.

Be sure to take into account the distance between the floor joists. Professionals call it a “step.” It is determined depending on the parameters of the floorboards. The thicker the floor covering, the larger the pitch can be. Accordingly, the thinner it is, the smaller the step we take.

A pattern can be deduced from the table. If the thickness of the board increases by 0.5 cm, then the step increases by 10 cm. For a more durable coating (for example, plywood and OSB), the calculations may be different.

Since these materials are more resistant to deflection, the pitch increases. With a thickness of 18 mm, the pitch will be up to 40 cm. With 25 mm, it will be up to 60 cm. We attach each sheet to three different lags. Be sure to fasten the center and edges, going halfway up the joists.

The logs are laid on wood, soil and concrete. First you need to know what tools are required for this. So, in addition to the bars themselves, you must have a level, a jigsaw or hand saw. We stock up on screws, screws, anchors and nails. Be sure to have a hammer drill with you (when laying on concrete), usually an axe, a screwdriver or drill, a hammer and a nail puller.

If the joist is attached to wooden floors it is necessary to fasten them to the sides of the beams. This is done based on the fact that beams are usually not level. In addition, this method helps not to raise the floor too high, saving precious centimeters in rooms with low ceilings.

If the height allows, then, as an option, the timber is laid on top across the beams. We secure them with 6 mm screws, having previously drilled a hole 2.5 mm smaller in diameter. This will prevent the wood from splitting. The length of the screw should be 2.5 times longer than the width of the joist.

When laying logs on the ground, it is necessary to clean and compact it in advance. Next, measurements are taken to install the pillars. They will serve as a support. The distance from the wall to the first log should be from three to twenty centimeters. Holes 10 cm deep are dug along the intended distance, filled with sand and filled with water for greater strength. This will be the foundation for the pillars.

It is recommended to make its size at least 40 by 40 cm. Then polyethylene is laid, and a column of two or three bricks secured with cement is erected on top of it. Then they are covered with roofing felt, and timber is laid on top. The logs are attached with galvanized corners to the walls or to the crown of the log house.

Joists are often laid on concrete base. Waterproofing in this case is extremely necessary, otherwise the floor will constantly become damp. It's quite regular one will do polyethylene film. However, experts are increasingly beginning to use foil insulation - this is foamed polyethylene with a layer of foil, which is placed towards the living space, reducing heat loss.

The beam is attached to the concrete using anchors. Insulation is laid between the joists, but not under them. Concrete screed, as a rule, eliminates the hassle of leveling joists before laying floorboards.

Make sure the wood is dried and treated with antiseptic or bitumen. This will significantly extend the service life of the structure. When the humidity is more than 20%, the tree can become warped, compromising the integrity of the structure. Boards brought from the warehouse must lie in room temperature a few days. This is especially true during the winter season. It is not recommended to lay the floor when the air humidity is less than 60%.

You should not saw or plane boards in the room where the floor is being installed. Sawdust can cause rot.

Don't forget to use waterproofing. For sound insulation, as a rule, fiberboard, rubber, polyethylene foam, slag or sand are used. Your home will remain warmer longer if you fill in the voids under the floor. mineral wool, expanded clay, polystyrene foam or isospan.

Use the rule after installation. Lay it across the beams, remove gaps, leveling the height. This is easy to do with the help of special modern adjustable mounts appeared on the construction market. The floor is laid only after all leveling procedures.

The smaller the pitch, the longer the floor will last. However, the main indicator of durability is the material of the coating and base. The most durable wood is larch.

The installation of beams is usually carried out along the window, i.e. across the room. The floor boards are then placed along the length of the room, i.e. from the window. However, this is just a recommendation and a matter of taste.

The floor is laid from the corner, placing the boards perpendicular to the joists. The distance from the walls should be about 1 cm. This is left in case the wood deforms depending on temperature and humidity environment. This distance is covered by the baseboard. If the boards lie close to the wall, the floor may swell.

A board is attached to each beam. Holes for screws should be drilled in advance to avoid delamination.

The most common option for the space between the joists is from 50 to 56 cm. As a rule, it does not exceed a distance of 69 cm.

Removing joists and wooden floors is quite simple. It is necessary to remove all furniture from the room, remove baseboards, open boards or chipboard sheets. After inspection, the old boards are replaced with new ones. The logs themselves can be partially replaced. Simply cut out a piece of rotten wood and install a new one.

Don't forget to use protective impregnation for new boards. Check the ends of the beams for rot, and inspect the base insulation, if any. Repairing the floor can be a reason to insulate your home.

Lags are deservedly the simplest and most popular way to create solid foundation of our gender. If desired, anyone can take up this interesting business and step achieve your goal step by step. The most pleasant reward for your efforts will be a warm and cozy atmosphere for many years.

Every experienced builder knows that in the process of making a floor in mandatory logs are used. This is the main element on which the quality of the floor structure depends. These elements are required to complete correct fastening floor and surface leveling. Without joists, the floor covering will sag freely under the influence of heavy furniture, and with every step on such a floor, unpleasant creaks and vibrations will occur.

Therefore, builders do not even raise the question of the need to use logs when installing floors. More important are other questions - what size should the logs be and how to install them correctly.

Why is laying joists so important?

The need to use logs when installing floors is due to their main function. They are needed to create a flat surface for subsequent work. At the same time, the sheathing installed under the flooring is capable of solving a number of other problems. These elements create conditions for ventilation bottom side flooring, which reduces the likelihood of boards rotting.

A timber base is especially necessary in rooms where the floor is planned to be laid on the ground or there is dampness, which can seriously damage structures even with a high subfloor.

The joists, which are traditionally placed between the decking and the subfloor, help create a special space - a kind of buffer that increases the soundproofing properties of the floor. This space plays another important role. This is where the insulating material and, in some cases, utilities are laid.

The logs cope with their task quite successfully even if they are laid on an uneven base. The support points created as a result of their use, which are placed at a certain distance, help ensure a durable floor.

Lathing materials

When installing flooring, you can use various materials, which are offered in construction stores. The main thing is that they have required strength, smooth surface and low deformation coefficient under load. Similar requirements are met by products made of plastic, metal, wood and reinforced concrete, as well as compounds made from synthetic resins.

If we evaluate all of the above options by cost, then wood can be considered the undisputed leader. Therefore, wooden beams are most often used when constructing the floor.

The material used for flooring is most often made from coniferous wood. As a rule, these are pine, spruce and fir. However, practice has shown that logs made of larch wood are the most practical. This is due to the advantages of the material, which is very durable and rot-resistant.

As for pine and spruce, they are chosen by owners seeking to save on material.

It is especially worth mentioning the rules for choosing material for making beams. These can even be bars that have resin pockets and minor defects. So you can safely purchase second or third grade lumber without worrying about the functionality of the base.

If your financial capabilities are limited, then instead of larch you can choose pine or spruce. Experts recommend not saving by purchasing wetter timber, as this can be fraught big problems. To make logs, it is necessary to take beams with a moisture content of no higher than 20%. If you do not comply with this requirement, then during operation the tree will dry out and become deformed, and this will require reworking the flooring.

If you decide to make the sheathing from spruce or pine, then you will have to carry out waterproofing without fail while laying the beams. Logs can be used when laying on any type of foundation, however, in each case, waterproofing will have to be done with some adjustments.

In the event that the logs are placed on a reinforced concrete base, then on initial stage a layer of foamed polyethylene must be laid.

In a situation where the beams are laid on brick pillars, polyethylene is used, which is laid between the posts and the ground, as well as between the post and the bar. To protect the space between brick and wood from moisture, you should use roofing felt rather than polyethylene.

Regardless of what type of wood you plan to use for the sheathing, before laying them you must treat with antiseptic compounds. First of all, this applies to those cases when the floor is laid in a wooden private house. Woodworms, which can very quickly damage floor elements and force the owner to undertake repairs earlier, can pose a danger to this structure.

Determining the dimensions

No less attention should be paid to the size of the selected logs. The fact is that this directly affects the reliability of the floor structure. Before you go to the store to buy timber, you need to accurately calculate its thickness and length.

How to calculate the length?

Determining the length of the varnish is quite simple. Attention must be paid to the direction of installation. All you need to do is measure the length or width of the room in which you are going to lay the floor. It is best to choose floor bars not exact dimensions, and 2.5-3 cm less than this value. If you fall short of the calculated value, you can prevent structural deformation when it begins to be exposed to temperature changes.

It is best if the floor joists are made of solid lumber. However, this is not always possible to achieve, since in some cases the length or width of the room differs from the dimensions of the timber. If it so happens that the beams are not long enough, then the problem is solved by merging the two elements. This operation is performed in half a tree; in some cases, galvanized overlays may be needed.

In principle, the operation of merging two bars is not so complicated. However, you must be sure of its strong connection, and this is only possible subject to the following rules:

A support must be installed at the splice location you choose. It is best if this is a reference column;
When merging two adjacent joists, care must be taken to ensure that their merging points are slightly offset from each other.

If you decide to neglect at least one of these rules, then after a while the rigidity of the floor at the place where the timber is joined will decrease.

When merging adjacent joists, you must perform requirement for their displacement by 1 meter. If you found out before installation that you will have to connect the beams, then when choosing lumber in the store required sizes you need to remember this.

Section calculation

Thus, determining the length of the beam is quite easy. Much more questions arise with the calculation of the lag cross-section. The section refers to the thickness of the logs, which depends not only on the material of the timber, but also on the calculated characteristics of the future floor.

When determining the cross-section of the joist for the flooring, it is necessary to take into account floor load limit, as well as the dimensions of the spans between the support points of the beams. Most often, a load of 300 kg/m2 is taken into account. It is optimal for cases where the floor is planned to be laid in residential premises.

If you are going to lay flooring in your home, then you should take into account the length of the span between adjacent beams when calculating the load. It must be remembered that the distance between the floor joists affects their thickness in a certain way. This is clearly demonstrated by the special size table used by specialists. IN general view This The correspondence can be represented as follows:

If the span is 2 m long, then it is recommended to choose a beam with a section of 110 x 60 mm;
For a span of 3 m long, take a beam with a section of 150 x 80 mm;
For a span of 4 m long, beams with a cross section of 180 x 100 mm will be required.

The main thing you must remember is that as the span parameters increase, it is necessary to increase the thickness of the selected timber.

As a rule, the beams used for floor sheathing have a rectangular cross-section. In order for them to cope with the resulting load, they must be laid “on edge”. This is one of the main requirements of floor laying technology, the implementation of which guarantees the maximum level of timber rigidity even with minimal volume characteristics.

Sometimes for flooring you can take sex logs with parameters, exceeding the recommended ones. Using them when installing a floor will not be a mistake. Moreover, in some cases this will be the only correct decision.

But you need to take into account that if you use timber with a larger cross-section, you will have to increase the thickness of the thermal insulation layer.

Before purchasing joist material, you must take into account the type of room where you intend to install the flooring. If this is a non-residential object, then the structure must withstand a load of more than 300 kg/m2. The exact value is calculated by calculation using special formulas, after preliminary measurements. When will you have exact values characteristics of the material, you can choose logs with the optimal cross-section.

It is not prohibited to replace wooden beams with metal ones or concrete beams. True, in this case it will be necessary reduce the thickness of the sheathing elements. The fact is that such beams withstand deflections much better than wooden logs.

How to determine the pitch of sexual lags?

When calculating the size of the logs, you need to take into account the size of the span between them, and it depends on the thickness of the board from which the structure is made wooden floor. To do everything right, you must follow next rule: As the thickness of the flooring boards increases, the step width must also be increased. This approach to calculating the size of the lag is explained by the fact that a thicker board will sag less when subjected to loads.

Boards 2 cm thick should be installed at a distance of 30 cm.
With a thickness of 2.5 cm, the step is increased to 40 cm.
with a thickness of 30 cm, the step can be made 50 cm.

To determine the span length for boards of greater thickness, it is recommended to perform calculations as follows: when increasing the thickness of the flooring board by 0.5 cm, add 10 cm to the lag pitch.

If the wooden floor is made of plywood or OSB, the calculations are performed according to a slightly different scheme. Here we have to take into account increased rigidity bending of these materials, which makes it possible to reduce the thickness. Thus:

for material with a thickness of 1.5-1.8 cm, you can choose a distance between the floor joists of 40 cm;
with a thickness of 2.2-2.4 cm, it can be increased to 60 cm.

The technology for installing a wooden floor using plywood or OSB sheets requires fastening the structure at three points. The floor joists must be laid in such a way that the joints are located at the edges of the sheet and in the middle. The edge of the sheet must be laid only up to half the width of the beam.

Conclusion

Work on installing a wooden floor requires special care at every stage. This is especially true for calculating the lag step. It is necessary not only to select elements with suitable characteristics, but also correctly calculate the distance at which they need to be laid. All these nuances are very important, because any error in the calculations can negatively affect the service life of the wooden floor.

Thanks to its environmental cleanliness, aesthetics, naturalness, warmth and comfort in the home, wood floors have not lost popularity to this day. When choosing them, many questions arise - what should be the distance between the floor joists in wooden house, what material to choose, how to install correctly, etc. This article will answer all your questions.

Choosing timber for logs

Select the material from coniferous wood, the price of which is low - spruce, pine or fir. If the room is damp, purchase larch slats. It is more expensive, but it almost does not rot from exposure to moisture.
To save money, you can purchase grade 2/3 lumber with a moisture content of 18/20%.
The bars must have rectangular cross-section. At the same time, their height should be 1.5/2 times greater than their width. Having such a cross-section, the logs will operate optimally, withstanding high loads.
The dimensions of the beam must be selected based on the span, that is, the distance between the beams bottom trim. The thickness of the insulation used is also important.

Below are the sections of the logs (with a step between them of 0.7 m) for different spans.

When the span width is of an intermediate value, you need to choose the closest option, taking into account the safety margin.
When purchasing timber, inspect it for defects. Before calculating floor joists, take into account their margin of 10/15%.

Note! To protect wood from harmful insects, mold and fungi, it must be impregnated with an antiseptic. The underside of the beams must be treated twice, allowing the first layer to dry for 4/5 hours.

How to determine the pitch between joists

This value depends directly on the thickness flooring.

Table you can use

When thick boards with good strength are used for flooring, logs can be installed relatively rarely. If finishing coat thin, the timber must be positioned frequently. Below is a table of distances between floor joists based on the thickness of the boards.

To more accurately determine the step between the lags, you will need to carry out calculations.

Calculation example

Let the length of the room be 11 m.
The width of the beam will be 0.15 m.
We will choose floorboards with a thickness of 25 mm (0.025 m) for flooring. Therefore, the gaps between the logs should be from 40 to 50 cm. Let’s average these figures to 45 centimeters, that is, 0.45 meters.
Let's denote the number of lags as x.
The width of all our logs will be equal to 0.15∙x.
The first beams will be installed at a distance of 30 mm (0.03 m) from the walls. Based on this, the step between the lags will be: x-1. The distance between all lags will be equal to 0.45∙(x-1).

To find out the distance between the floor joists, we create the equation:

length of the room = width of the beam + gap between all the joists + distance from the walls.

We substitute the values: 11=0.15∙x+0.45∙(x-1)+0.06.
We solve the equation:

11=0.15∙x+0.45∙x-0.45+0.06;

11=0.6∙x-0.39;

The number of lags must be an integer; based on this, we round the value to 19.
The sum of all the gaps between the logs will be equal to 11-0.06-19∙0.15=8.09 meters.
We divide this figure by the number of distances - 8.0919-1=0.4494.
The result obtained: the exact distance between the floor joists should be 44.94 centimeters.

Frame installation

Floors with joists can be installed both on the floors of the house and on the ground base.

Installing joists on wooden floors

The logs must be fixed to the strapping beams. It should be taken into account that they are unlikely to have an absolutely even level. Therefore, it is best to attach the timber to the sidewalls of the beams.
In this case, determine the horizontalness of the joists using a control strip; no backing can be used.
Fix the logs with screws with a diameter of 6 mm. They should be 2/2.5 times longer than the width of the beam.
To prevent the lumber from cracking, drill holes in the joists and beams. In this case, use a drill that will have a diameter 2.5 mm smaller than the size of the screw.
When the beams are located far from each other, you need to install double logs. First, lay the first row of joists on the beams, and on top of them, with smaller steps, another one.

Laying timber on the ground

First, level and compact the soil with your own hands. This work can be done using big log. Nail a board to it from below and, moving the tamper along the ground with a partner, compact it. The board should be at least 5 cm thick and slightly larger than the cross-section of the log.
Next, mark up for support pillars for lag. When the supports for the frame are the beams of the lower frame, marks can be left directly on the beams. If the support is a grillage covered with roofing felt, place marks on the waterproofing material.
The distance from the initial logs to the walls should be 3/20 cm.

Before installing the support posts, you need to make a foundation for them. It can be poured separately under each support or placed under a row of posts.

The dimensions of the foundation for the column are minimum 0.4×0.4 m, height 0.2 m, 5 cm of which should protrude from the soil.

The instructions for arranging the foundation are as follows.

Set aside 0.2 m from the log axis marked on the strapping beams in both directions.
Pull the string between the marks.
Perform a similar operation in a plane perpendicular to the joists to mark the corners of the posts located at the intersection points of the cords.
Drive stakes into the corners. Next, remove the cords.
When the foundation is laid under a row of supports, only the edges of the row are marked with cords.
In the marked areas, remove upper layer soil. Compact them, pour in crushed stone and compact it.
Assemble the foundation formwork, which has a height of 0.1 m.
To waterproof concrete, place polyethylene film in the holes. If the soil is clay, then you don’t have to do this.
Reinforce the foundation with a frame welded from rebar, 0.8 cm in diameter. It should be laid slightly below the center of the future concrete layer.
Next, fill in the solution. Its composition should be the same as for the foundation of the house.
Allow the concrete to set for 2/3 days.
After this, lay the waterproofing. For this purpose, cut pieces of roofing felt according to the size of the supports, in other words, 40x40 cm. You can also make overlaps of 1 centimeter. Lay the insulation directly on the mortar; there is no need to coat it with bitumen.
Now you can start laying bricks. Two rows of them in height are enough, the top one should be oriented perpendicular to the length of the beam. To fasten the material, use sand-cement mortar, brick use grades not lower than m-100.
Lay waterproofing along the bricks.
Place soundproofing pads on top of it. To prevent them from moving, secure them.

First, lay the lighthouse logs, the first from the walls. Secure them at intervals of 2 meters from each other.

Note! Check that the material is laid horizontally relative to the ground, as well as to each other. If the logs lie unevenly, the protruding areas can be removed with a plane, and pads can be installed under the sagging parts. It should be taken into account what maximum deviation is permissible - it should be one millimeter per 1 meter of timber.

Conclusion

The strength and reliability of the structure of all floors depends on the pitch of the joists, their cross-section and the wood used. Therefore, you need to take the choice of these parameters seriously. In the video presented in this article you will find Additional information on this topic.

In order for a floor made of such a popular material as plywood to be strong, reliable and durable, you must first correctly calculate the distance between the joists. Moreover, the correctness of this work largely depends overall quality construction or repairs at the site. We will tell you in this article how to calculate the distance between the power supports of floors and platforms on top of which plywood is placed.

What are lags?

First of all, you need to understand the definitions. In construction, logs are traditionally understood as a common base or strength element of platforms and floors, which takes on the main static and dynamic loads caused by the presence of equipment or furniture in the premises, the movement of people, etc. They are traditionally used and if the floor is such wood material like plywood.

Logs are made mainly from wood, and from coniferous trees. The resin in their composition additionally protects the plywood from moisture and extends the overall service life. Sometimes larch and other woods are also used.

In fact, logs are wooden beams of the required (pre-calculated) cross-section, which are located on the base of the floor. They act as an intermediate supporting element between the plywood and the screed.

The main functions of the log include the following:

ensuring uniform distribution of existing loads on the floor and underlying elements;

increased sound insulation qualities (besides, logs in tandem with quality plywood provide additional thermal insulation of the floor);

the ability to hide various communications under plywood (Internet cables, wiring, etc.) while maintaining relatively convenient access to them and minimal maintainability parameters;

affordable costs for installing joists, provided that a flat floor surface is ensured (this is true for most floor materials - rolled or wooden).

Why calculate the step between lags?

Any construction material has its own parameters of strength, reliability, durability, etc. This is also true for lags. To prevent the plywood from bending later or the floor losing its original parameters, you need not only to select support beams that are suitable in cross-section and thickness, but also to select correct distance(or step) at which they will be located from each other.

If the correct and competent calculation is made, then the logs will effectively perform their functions, plywood or floorboard you won’t have to re-lay it soon, and the overall costs of arranging the floor of the room will be minimized.

In addition, it is important to take into account the specifics of the object. Lags in panel houses installed from above reinforced concrete floor. In this case, the cross-section of the timber can be chosen to be minimal, so that it is simply possible to fasten plywood or other flooring material. In frame wooden buildings the support also performs a power function for floors and can be connected to wall supporting structures etc.

What is important to consider when making calculations?

To lay plywood, you first need to determine the pitch between the support beams used in this case - the distance of one lag from another. But first, you need to collect the initial data that will be required for the calculations, namely:

plywood thickness;

maximum floor load (per 1 square meter of area);

the distance between the walls and the number of support points.

Even these parameters are quite sufficient to determine optimal step and lay a reliable and practical floor from plywood of suitable thickness and other parameters.

You also need to first determine optimal cross section for lag. In this case, the total distance of one support (wall) to another is taken into account - this is the size of the span and the required load-bearing capacity of the floor. Typically, when using plywood, maximum load taken as 300 kg per square meter. After this, rectangular beams (the part that is wider is placed vertically) or square beams are selected as lags, and when choosing the thickness of the beam, only the size of the span is taken into account:

for 2 meters - width up to 10-15 cm;

2-3 meters - 15 cm;

span 3-4 meters - log width 18 cm;

5 meters - 20 cm;

6 meters - 22 cm.

Simultaneously with the increase in width, the height of the bar is gradually increased - by 1-2 cm, with the initial value for a 2-meter span being 6 cm. If the boards are so

There is no such size, then it is permissible to place a piece of plywood or other boards of suitable width and length on top of the timber. Moreover, even without tying or gluing, you can get the effect of a solid log without damaging the floor.

Step calculation

Having determined required section lag can be considered the distance between the support bars for plywood or other flooring material. If the previous calculations were carried out correctly - taking into account the loads and spans - then the calculation of the step is simplified. In order to determine the distance for the log, it is enough to take into account only the thickness of the material used, that is, plywood, floor boards, etc.

IN construction industry a direct relationship has long been determined - the thicker the material, the wider the support beams can be placed. We recommend that you adhere to the following recommendations:

if the plywood thickness is 20 mm, then the lag pitch should be 30 cm;

boards 24 mm thick are used - distance 40 cm;

30 mm plywood is used - 50 cm;

board thickness 35 mm - 60 cm;

for thick materials 40-50 mm thick, the step should be from 70 to 90 cm, respectively.

In this case, the calculation method must change if chipboard (chipboard), oriented strand board (OSB) and other products are used as a rough floor covering. These building materials are actively used as foundations for masonry ceramic tiles or using linoleum, laminate, etc. You need to take into account the overall strength and bending rigidity; if they are lower, then the step should be taken less.

If there is any doubt about the distance for the support bars under the plywood, it is better to shorten the spacing. In this case, the overall strength of the floor will only be higher.

What are the consequences of errors in determining the step between lags?

Wrong preparatory stage and errors with the choice of cross-section or distance of supports can directly affect the finishing coating. The most likely consequence if the step is set too large is sagging of the plywood, the risk of cracks or sagging, cracks in the tiles, and clearly noticeable unevenness of the rolled flooring materials. This negatively affects not only the appearance, but also the overall performance properties. And as a result, a complete or partial rework will be required.

Even bigger Negative consequences errors in calculations may occur if created interfloor ceilings. If the pitch is seriously overestimated (for example, in order to save on materials), the overall strength of the structure suffers greatly, and the risk of deformation and complete destruction increases.

How to carry out calculations or who to entrust this work to?

It doesn't matter whether you use plywood or other rough materials on top of the supports. flooring materials, any miscalculations and inaccuracies in measurements and preliminary calculations must be excluded. How to do it? Entrust this work to those who understand it:

do it yourself, but carefully checking the standards and recommendations, checking the initial data and making roundings only in the direction of increasing the cross-section of the logs or reducing the step between them;

entrust the calculation design organization, which employs qualified professionals;

apply modern software or online calculation calculators, using several options to check.

This is the only way to mount both the supports themselves and the entire structure with maximum reliability, and ultimately guarantee the strength of the building and its attractiveness. appearance and durability.

All parameters must be specified in mm

X— Floor width.

Y- Floor length.

S1— Lag width.

S2— Thickness of the logs.

S3— Distance between lags.

O1— Width of floorboards.

O2— Thickness of floorboards.

O3— Width of the subfloor board.

O4- Thickness of the board.

R— Distance between boards.

With help online calculator You will be able to calculate:

Volume of log materials;
Calculation of floor joists: length, width and required quantity;
Total floor area or square footage;
Number of rows and volume of floor covering;
Number of sheets of wood, laminate or parquet;
Volume between joists for insulation;
The amount of material for the subfloor.

Helpful information

Wooden flooring is made in three tiers, as shown in the figure above. At the bottom there are load-bearing logs on which rough boards will be laid, and on top there are finishing floor boards. Below we will describe the installation technology in detail.

DIY wooden floor

As a rule, this work is carried out after completion heating season. Since at this time, the boards will not absorb excess moisture. The weather should be dry and sunny. It is best to use unplaned boards for rough flooring. While milled and dried boards with longitudinal groove for ventilation. Boards with a curved edge for a groove connection. As a rule, each such board is pre-treated with a decorative and protective composition.

During the installation process, you must follow the requirements:

All logs must have good stability;
The logs are laid strictly horizontally (exception when the slope is provided for by the project);
Ensure ventilation of the space under the floor;
Wood moisture content should not be more than 12%.

Mark and prepare the floor surface

First of all, we mark out the room and designate the places that need to be planned in order to achieve single level(taking into account the thickness of the seams and the height of the brick). To add incompressible soil, use fine crushed stone or sand with a layer thickness of up to 5 centimeters.

After this, compact the entire surface. In those places where the logs will be located, we fill in crushed stone and also compact it into the ground.

Installation of logs

Can be used as a lag wooden beam size 50x100 mm. According to your program results, we install the timber on an already compacted surface.

If you plan to increase this distance between the lags, then in this case you should use a larger section of the beam.

If the subfloor base has concrete floor or slabs, then we install the logs directly on the concrete. In this case, you can use a smaller cross-section of the beam, since the bending load is almost completely eliminated. The rough flooring will act as a retainer for the second tier, and therefore a section of 50x50 is sufficient.

The distance between the logs will depend on the thickness of the material being coated. For example, 60 centimeters for a milling board, 40 centimeters for covering OSB or plywood.

When the logs are installed, we move on to waterproofing the space underneath them using roofing felt or other modern material.

Rough layer

When the logs are laid, we begin to install the second level, namely “rough boards”. To do this, all end joints should be made directly in the middle of the joists. To fix the boards, we use wood screws of the required size. You can either press the rough boards against each other or nail them at short intervals. In our case, this interval is determined by the value R.

Nails should be driven towards each other at a slight angle for strong fixation.

If you are laying with milling boards, then it is not enough to press them together by hand. For this purpose, special stops and wedges or tightening devices are used.

To fix the finishing board we use nails or wood screws.

The caps of fasteners should not be higher than the surface of the board. To do this you need to go deeper by 2 millimeters. The recesses can be treated with a special putty before painting the floor.

If you use screws instead of nails, you will need to drill holes and subsequently countersink each recess.

During the installation process, a gap of 10-15 millimeters must be left between the wall and the end of the joist or the outer boards, which will subsequently be covered with a plinth. This gap will serve as a compensator in the process thermal expansion or moisture swelling.

The flooring is ready, now it can be covered with stain or protective varnish.