How to install joists on the roof. Detailed guide to installing floor joists

You want to make a roof yourself, but don't know where to start. In principle, every person understands that the roof is an integral part of the house. That is, without a roof, a house is not a home.

Do-it-yourself construction will help you not only gain experience, but also save a lot of money.

After all, almost half of construction costs goes to pay hired workers. And only when you do the roof yourself can you be one hundred percent sure of the quality of the work performed.

The structure must be light, since it puts pressure on the walls and foundation, and at the same time strong, so that it can withstand the weight of the roof and a large amount of precipitation and strong winds. The roof is a construction kit, so to speak, which is best assembled by a company of three people (more are possible).

The basis of the roof is a frame, which consists of straps. The straps are installed on the ceiling joists. A ceiling joist is a beam that is fixed to the walls and, after covering with boards, forms the ceiling in the house and the floor in the attic. If you do not plan to use the attic as a room, you can use bars measuring 50 × 150 millimeters.

And if you decide to make yourself an attic, then use beams for ceiling joists 150 × 150 mm. If the house is brick, it is advisable to use maurlat. This is a beam that is fixed to a brick wall around the entire perimeter of the house. It is attached using studs pre-installed into the wall or armored belt.

For straps used in construction, edged boards measuring 50 × 150 millimeters are used. The logs are displayed in the form of a hut (letter Λ). First we place it along the edges or along the brick gables. These will be the templates according to which we will make all other lags.

The frequency of lags depends on the material from which the roof will be made. From the two installed straps we pull three cords (at the top along the ridge, in the middle, at the bottom). The straps extend beyond the outer part of the wall by at least 30 cm; the larger the extension, the less precipitation will fall on the walls.

Then we install all the rest, securing them with braces or sheathing boards. Next, we place a support beam in the middle of each strap. If the roof is attic, the support can be moved slightly to increase the usable space.

We place the top of the straps end to end with each other and embroider them at the top with a block (if the roof is attic, we fix the block at the height of the desired ceiling). All fastenings should be made using self-tapping screws.

We fasten the straps to the joists using metal staples. After the straps are set, we cover the top with lathing. For the sheathing, an inch board is used, or an unedged one. Just remove the wane from the boards (bark along the edge of the board). We lay waterproofing on the sheathing.

And already for waterproofing with a stele roofing material of your choice (slate, tiles, etc.). For construction, use dried lumber.

The quality of laying the finishing coating on a rough base is largely determined by the correct assembly of the lathing from the logs. In the process of finishing the subfloor, all technological standards must be observed, otherwise the structure will quickly deform, which will lead to damage to the finished floor. In the article we will look at the features of installing logs on strip and monolithic foundations, and also dwell in more detail on the nuances of installation finishing coating.

About lags

The logs are heavy wooden beams with a rectangular cross-section, which are used in construction to level and insulate the subfloor. Installing a floor on joists is one of the most popular solutions when arranging a rough foundation. National team wooden sheathing from beams can be used for laying many types of finishing coatings, which include:

solid boards and parquet;
laminate and linoleum;
ceramic tiles and carpet;
plywood and cork flooring.

Advantages of a subfloor on joists:

Good sound and noise insulation, which is formed thanks to air gap between the wooden sheathing and the base;
Uniform distribution of static and dynamic loads across beams;
Laying floor beams with your own hands allows you to lay communications under the floor;
Thanks to the air layer between the base and the wooden structure, there is always circulation under the floor air masses, which prevents condensation accumulation;
If the beams are placed correctly, the structure can withstand a load of 5 tons per m 2 of coverage;
With the help of logs you can build almost any foundation: monolithic, pile, strip, etc.

Laying wooden sheathing on the ground ( strip foundation) poses some difficulties. Wooden beams are hygroscopic, therefore groundwater, “washing away” the wood, can lead to its destruction. To avoid this, do-it-yourself installation of wooden elements is carried out on a layer of waterproofing.

Features of choosing wood

A properly prepared subfloor is the key to the “longevity” of the finishing coating. So that over time the wooden sheathing does not deform or sag, during the selection process suitable wood The following points need to be taken into account:

You can make a leveling sheathing with your own hands only from beams rectangular section. They are stronger and more stable, which gives the wooden structure considerable rigidity;
The lags are laid on edge, and their height should be at least 1.5 times greater than the width;
The most reliable material for beams will be oak, larch or aspen. Boards made of spruce, fir or pine have less strength;
When laying beams on a strip foundation, care must be taken to carefully treat the wood with non-hygroscopic compounds;
If you need to make a final coating that will be opened with varnish, you can limit yourself to choosing premium grade wood;
The highest grade of wood for the finishing boards is taken if you plan to leave the floor with a natural look.

Design features of the log

To make a reliable and durable ceiling with your own hands, you need to consider some technological nuances, namely:

Floor beams are laid using only 2nd and 3rd grade wood;
The approximate moisture content of the boards should not exceed 18-20%, otherwise they will become deformed when drying;
Beams should not have significant defects, the size of microcracks on them should not be more than 1 cm in length;
To avoid a shortage of wood when arranging the floor in a private house, it is better to purchase boards with a reserve: +10% of the required quantity;
Before or after laying the logs, the wood should be treated with an antiseptic to prevent the appearance of mold;
The lower part of the finishing boards should also be treated with potassium fluoride or ammonium fluoride;
Installation of logs is carried out with a certain step, which directly depends on the thickness of the finishing coating: the wider the step, the thicker the finishing floor should be.

You can find out more in the video below.

The nuances of installing beams on a concrete floor

Leveling a concrete floor when installing a wooden structure made of beams can be done in the following ways:

Using a tie. You mix up a cement-sand mortar with your own hands, which helps level out height differences on the base. It dries within 3-4 weeks;
With the help of lag. When arranging the base on logs, it can be leveled with adjustable beams.

Since wood exposed to moisture will be laid on the foundation, the following sequence of work must be followed in the process of preparing the floor:

On concrete covering You should first put a layer of waterproofing - polyethylene, glassine, roofing felt, etc.;
When preparing the floor in multi-storey building It is advisable to also lay a layer of sound insulation;
Then the logs are installed on the prepared base in increments of 30-40 cm with a final coating thickness of 4-5 cm;
As a heat insulator placed in cells between the beams, you can use mineral wool, ecowool, polystyrene foam granules, etc.;
At the final stage, the final covering is laid with your own hands - laminate, parquet, plywood, solid boards.

A video will help you understand the topic better.

The nuances of installing beams on the ground

A strip foundation is one of the most difficult, from a technical point of view, bases for installing wooden sheathing. In a private house, this type of foundation is used quite often, especially in modern buildings. Making a rough base on the ground with your own hands is very problematic, since in the process of assembling the floor you need to take into account many points, namely:

The soil is leveled and compacted well;
A “point” foundation is made of several brick columns along the perimeter of the room;
The height of the underground should be approximately 20 cm, so the columns should be strong enough and high;
A layer of waterproofing (roofing felt) should be placed between the formed supports;
When setting up a strip foundation in a private house, the beams are placed with a distance of 30 mm from the wall;
To insulate the base, granulated expanded clay, sand or crushed stone are placed in the cells of the sheathing;
Then the logs are “adjusted” and attached to the support posts using special anchors;
At the final stage, the finishing coating (plywood, parquet, laminate) is laid.

Determining the distance between beams

What distance should be maintained between the beams when assembling the floor sheathing? The service life of the finishing coating depends on the correct assembly of the wooden sheathing. Why? If the distance between the bars is made too large, finishing material will experience greater stress. Over time, this will cause the finish to warp and crack.

How to determine the required distance between the bars? If a durable board 4 cm thick is used as a finishing coating, the logs can be laid at a distance of 0.6-0.7 m from each other. If the thickness facing material will be less than 2.5 cm, the distance between the beams will have to be reduced to 30 cm. In rare cases, when laying fairly thick wood - more than 5 cm in thickness, the beams can be installed at a distance of 1 m.

Selection of finishing material

In a private home, often as finishing coating boards are used. Today, milled boards with a tongue-and-groove system are the most popular. The thickness of such material ranges from 2.9 to 4.5 cm. Using such wood as a finishing coating, you can achieve the maximum lifespan of the floor - more than 10-15 years.

Also, installing a floor yourself involves installing the following types of coatings:

solid boards with trapezoidal tenons;
plywood and parquet;
laminate and linoleum;
tongue and groove board.

For laying laminate, parquet and similar materials when arranging the floor on joists, the wooden sheathing is pre-sewn OSB sheets or plywood. As already noted, the distance between the beams will be determined by the thickness of the facing material.

Features of finishing flooring

Scheme of laying tongue and groove boards on logs

How to properly lay a board on a joist floor? To achieve maximum strength and wear resistance of the floor, when laying the boards you need to take into account the following points:

The floorboard begins to be attached from the wall, which is located opposite the door entrance;
There should be a technological gap of 15 mm between the wall and the floor board in case of wood expansion;
The location of the boards must correspond to the direction of the light; they are laid parallel to the light entering the room;
The material is secured using self-tapping screws, the length of which should be 1.5 times the thickness of the finishing coating;
In a similar way, 3-4 rows of boards are laid, after which the laid material is inside they are tightened with a metal bracket so that the floor does not “walk”;
You need to tighten the covering with metal staples every 3-4 rows of laid boards.

The roof is perhaps the most remarkable part of any building. And remarkable – not only because it can be seen from afar.

Absolutely any building - a house, a bathhouse, a cottage, even a barn - changes its appearance beyond recognition, as soon as the roof is changed. And the importance of the roof in the life of the building itself simply cannot be overestimated. Has the corner of the foundation crumbled? – it’s okay, if, of course, it doesn’t collapse further. Gaps in the walls? - Well, it’s cold in the house, we need to heat more. Are the windows and doors falling off? - Let's support it with a board!

But if the roof leaks, then the most notorious quitter takes a tool and starts putting patches on it! And the point is not even that the water is down the neck, but that if the roof leaks, the house will remain a house for no longer than a few months. Then, in addition to the roof, you will have to repair everything - walls, ceilings, floors, ceilings, and foundations, and overhaul them!

The introduction is long, but the conclusion follows from it - installing a roof is a very important task! So the majority is looking for specialists to have their dacha roofed, or to have the roof replaced on an inherited house in the village.

Meanwhile, in order to deliver a good strong roof, one pair of hard-working hands is enough. Better, of course, two.

The basis of the roof is its rafter structure; it is this that determines the shape of the future roof, its strength, and its rigidity.

For device roofing structures have not been used for a long time round wood(simply logs), firstly - to make the roof itself as light as possible, and secondly - to reduce its cost, timber is now an expensive material.

The truss structure of a modern roof (everyone understands that we are talking about private buildings, and not about block high-rise buildings) is built from edged boards 50 mm thick. The width of the board must be selected based on the size of the future roof, from 150 to 250 mm.

That is, the roof of a bathhouse, for example, measuring 3 * 4 m2, with a projection of 2 m, can even be made from a 50 * 100 mm board, although I would recommend 50 * 150 mm, and a design for a good country house, even 6 * 10 m2 , we make it from a wider board - 50-250 mm, everything is clear here.

Use for load-bearing structures edged lumber very convenient, since it allows you to make almost any, most intricate, roof structure very quickly, with little labor, and provides scope for creativity.

The simplest device gable roof seems like a very easy task, so as an example, let’s look at a slightly more complicated structure – an attic roof.

The figure shows perhaps the simplest version of the rafter structure for an attic roof.

By way of clarification:

A. Floor joists made from the same edged board as the entire structure.
B. Vertical racks, they will bear the majority of the distributed load, both of the roof itself and of possible snow accumulation. As can be seen from the figure, the racks rest directly on load-bearing walls, relieving the floor from the load.
B. Rafters for attaching the formwork to the side of the roof. It can be seen from the figure that the load will fall mainly on the floor joists, but since the slope is very steep, the load will only be the weight of the roof itself.
G. The rafters of the roof itself. The paired fastening gives them greater strength and ease of fastening the remaining parts of the structure.

Probably no further explanation is needed. Having in hand good tool, preferably electric – circular hand saw, powerful drill, sets of drills and bits for it, and, of course, a little practical knowledge, it will not be difficult to assemble such a structure, even alone. The boards are brought upstairs, cut out and assembled right there; the assembled structure weighs a lot.

When constructing a hip, hip, or half-hip roof, the parts are easily connected by inserting already installed transverse rafter structures into the right place. (Fig.2)

The method of fastening parts can, in principle, be any; it is possible by drilling holes in in the right places, tighten the parts with pins? 12-16 mm, is it possible, without further ado, to simply turn the fastening points with self-tapping screws? 4.2 mm, preferably galvanized, for which you will need bits or sockets for a drill nut.

The lateral extensions of the joists must be made at least 0.5 m; this will protect most of the walls from precipitation, even in strong winds.

Horizontal floor joists are shown in the form of a pair of boards, conditionally, it can be timber 200*200 mm, 250*250 mm, the logs in such a structure are not loaded, and it makes no difference what they are made of. In the case of logs made of timber, you will have to select grooves in them to install the corresponding parts in place, but this is not at all difficult.

Don’t be confused by the fact that in the picture the logs are simply “lying” on external wall, in reality this is, of course, not the case, it is drawn so as not to complicate the drawing. The logs where the structure of the future roof is attached are already laid in place, in the corresponding wall opening. This place where the floor joists are removed from the wall is the most weak point in terms of thermal insulation, so it should be carefully caulked and filled polyurethane foam, not to mention the fact that, in the case brick walls, securely separate the wooden part with waterproofing.

You can carefully maintain the dimensions of each part by preparing them all before starting to assemble the structures. Then, having assembled the first structure using a tape measure and a square, it can be used as a template, which will greatly reduce the time for assembling the rest.

It took the author of the article about 6 hours to make eight of these structures alone. Install it already finished parts it won’t work alone, besides the fact that the structure weighs a fair amount, each of them needs to be positioned very carefully, controlling the plumb line both longitudinally and vertically. transverse roof planes.

The rafters, installed one after another, are fastened together by slopes, and when assembled they form a rather rigid structure. The width of the step between the rafters can be any in the range from 1.2 m to 0.6 m, here you need to proceed from the material of the future roof. Under a light ondulin roof, it is enough to install structures with a pitch of 1.2 m, the roof soft materials, for example, “katepal”, provide for covering the roof formwork with strong and rigid plywood, that is frequent installation not needed either.

But if you decide to get a tile roof so that it can serve even your grandchildren, then it is better to set the rafters in small increments, no more than 0.6 m. This will avoid sagging of the sheathing, formwork and the tiles themselves in the future.

We need to talk about the construction of the roof itself separately; I would just like to add that when installing an attic under the roof, it is necessary to sheathe truss structures Of course, you will have to use solid formwork made of boards.

Discuss the article on.

Wooden bath floors have been used since ancient times. And today, despite the presence large quantity new technologies, this option is rightfully considered optimal. We will look at several solutions for arranging floors, talk about the technology of their construction, advantages and “problematic” aspects.

Ground logs
Making wooden floors

There is only soil under the floor joists
Logs for the floor in a log house

This means that there is nothing under the floor except soil. The logs themselves, of course, never rest on the ground or various bedding; they need to be installed on concrete or brick pillars.

Lags on brick pillars
Columns made of blocks for logs

The distance between the posts is calculated taking into account the thickness of the joists, floorboards and maximum load on the floor. During the construction of baths, in most cases no one makes such exact calculations, and they are not needed. The average universal values are selected; in our case, we choose the thickness of the floorboards 30 mm and the joists 50×100 mm.

In this option, the distance between the logs should be within 1.5 meters, the distance between the columns under each log should be within 1.6÷1.8 meters. A few centimeters in one direction or another does not make a difference; move the columns taking into account the specific dimensions of the room.

The main thing is that the columns should be evenly spaced over the entire area.

Lag pitch depending on the thickness of the floorboards
Log dimensions at a pitch of 70 centimeters

How are floors with joists on the ground made?

Step 1. Take measurements of the room and determine the floor level. Construction documentation has its own characteristics. One of them is that the zero mark does not touch the ground, as some people think, but the floor level. Everything above the floor is indicated in the drawings with a “+” sign, everything below the floor level is indicated with a “-” sign. This means that the level of the logs should be indicated as -30 mm (below the thickness of the board). One more note on the documentation. Accuracy in millimeters is indicated in mechanical engineering; in construction, dimensions are in most cases indicated in centimeters. We will gradually move to standard size designations construction projects, for now we use familiar, but not entirely correct, notations.

Support posts for logs on the ground - diagram
Design wooden floors by columns

Step 2. Taking into account the distances, pre-calculate the installation locations of the posts and their number. The depth of the columns is approximately 20÷25 centimeters.

Mark the columns. On the opposite walls of the room, use a laser or hydraulic level to mark the zero mark (the level of the upper surface of the floorboards). Subtract 30 millimeters (thickness of the boards) and 100 mm (thickness of the logs). The level of the upper surface of the column is -13 centimeters. On the walls of the bathhouse, make another mark at this height.

Along the rope at the required distances, dig small square holes of this size; the depth of the holes is enough to make one bayonet of a shovel. Level the bottom and remove any loose soil.

It is highly advisable to pour a sand cushion 10÷15 centimeters thick to compensate for soil swelling during freezing/thawing. Place a layer of sand at the bottom of each hole and compact it. If you want to fill holes, do it concrete mortar in proportions of 1 part cement, 2 parts sand and 3 parts crushed stone. When pouring, make sure that the surface is smooth and horizontal.

Step 3. Prepare all materials. There are several options for posts: pour concrete into the ground or use concrete blocks. Above the ground, you can use red brick or blocks; between the concrete base and the brick, be sure to waterproof it with roofing felt. Take better brick, its small size facilitates the work of bringing the columns to one level of the horizon. The blocks have to be cut, it takes a long time, the cut turns out uneven.

Brick support column - appearance

Step 4. Making columns. We make the dimensions of the posts to match the brick, the standard length of the bricks is 25 centimeters, take two bricks. This means that the side of the square column will be 25 centimeters.

Do you have some concrete blocks available? Great, the work will go faster and easier, lay out columns of them.

The concrete has hardened - you can lay bricks. Thickness standard brick only 6.5 centimeters, such dimensions will allow, by changing the thickness of the solution, to accurately adjust the surface of the columns to required height. You need to tighten new ropes, pull them according to the height marks of the posts. Check the position of the bricks with a level; the posts should be in a vertical position. Using cement-sand mortar, accurately adjust the surfaces of all posts along the thread.

Step 5. The logs are laid on roofing felt; it is better to lay two layers of waterproofing.

The length of the logs should be 3–4 centimeters shorter than the length of the room, this is necessary to compensate for the expansion of the tree. The joists must be fixed to the walls in a sliding manner to prevent them from tipping to the side, but allow them to move slightly in the longitudinal direction. It is better to do this using factory standard metal connections, these are used during the construction of a floating rafter system. If it is not possible to purchase such connections, no problem, make them yourself. For this, on the one hand metal corner The holes need to be made oblong. This side will be attached to the joists with self-tapping screws; do not tighten the screws with great force, the joists should be able to slide. The second side of the metal corner is fixed to the wall of the bathhouse.

First you need to fix two opposite logs, pull ropes between them and lay everything else along it. If there are problems with the level, use different pads. Variation in height up to two millimeters can be allowed; these irregularities are eliminated over time finishing floor coverings.

Step 6. Laying boards. Check the quality of the boards; it is better not to use materials with visible signs of defects. If the boards are curved as a result of a violation of production technology lateral surface– you need to buy ready-made ones or make them yourself special devices to tighten them.

For these purposes, you can use ordinary metal staples and wooden wedges. Prepare several wedges at once with different slope angles. Metal staples are driven into the joists, an unnecessary board is placed between them, and wedges are driven in between the floorboard and it. The driving force should ensure leveling of the surfaces. The boards are fixed to the joists in this clamped position; after driving in all the nails, the wedges are removed and a new floorboard is inserted.

Bowrench – a tool for tightening floor boards

Do not forget to leave a gap of 1-2 centimeters wide near the wall to compensate for linear expansions; the gap is then closed with a plinth. For flooring, you can use both ordinary and tongue-and-groove boards. If all operations were performed correctly and the boards have no deviations in thickness, the floor is ready for final painting or varnishing. If there is a noticeable difference in the height of individual boards, then you will have to level them with a special manual jointer.

To improve the quality of the coating, the floor surface can be sanded.

Step 7 Nail the baseboards around the perimeter of the room - the floor is ready for use.

Fastening wooden skirting boards

There are two more nuances to installing floors in a steam room. The technology for laying the boards changes slightly depending on how the water will drain. If gravity flows into the cracks, do not pull the boards tightly, leave a gap of several millimeters between them.

If water goes into the drainage system, you need to make a hole. The best option- have electric jigsaw. Drill a “starting” hole in the board with a drill, insert a jigsaw knife into it and carefully cut out the hole the right size. No jigsaw - use a chisel and chisel. The work gets a little more complicated, but it's not scary. Small irregularities in the hole made in this way will be covered with a decorative drain grate.

Joists over concrete screed

A more complex and expensive flooring option. The logs are placed on a flat concrete screed; the floors can withstand significant loads.

Step 1. Mark the floor level and place marks on the wall. You need to mark both the position of the joists and the position of each layer of the cement base.

Step 2. Level the soil surface and remove the top fertile layer. You need to pour a base of sand or gravel onto the ground; compact the base using special vibration mechanisms or manually.

Example of compacting a sand cushion

Step 3. Prepare the concrete solution. When making concrete, we recommend using two parts sand and three parts crushed stone for one part of cement. This concrete recipe can be considered universal; it is suitable for the manufacture of most architectural structures of buildings using concrete.

Step 4. Pour the concrete base. You need to fill along the beacons.

For beacons, you can use purchased metal or ordinary ones. wooden slats. The slats do not need to be pulled out of the solution; they do not affect the final performance characteristics. Use a level to check the flatness of the concrete. If there are significant deviations, make a screed on top cement-sand mortar. Do the screed according to all the rules, do not allow unevenness or horizontal deviations.

Prices for cement-sand mixture

cement-sand mixture

Video - Installation of beacons under the screed

Video - Beacon screed

Step 5. Between the concrete base and wooden joists install waterproofing.

If you do not plan to insulate the floor, then you can take 30x50 mm bars as joists and lay them flat. The large support area of the logs completely eliminates their deflections, and the thickness is sufficient for strong fixation of the boards. The time lag must take into account linear expansions due to changes relative humidity wooden structures.

Video - How to lay joists on a concrete floor

Step 6. The boards are laid in the same way as we described above using the example of laying them along joists on the ground.

In cases of bathhouse construction, this flooring method is used infrequently. Such floors can only be made in a relaxation room; the method is not suitable for a steam room or shower. Laminate flooring or soft floor coverings are laid over plywood. The thickness of the plywood is determined general loads, but in any case it should be more than one centimeter. Depending on the thickness of the plywood, the pitch of the lag is adjusted. Experienced builders It is recommended to install logs at a distance of no more than 50 centimeters.

Laying plywood on joists

Plywood in mandatory must be moisture resistant; ordinary cheap varieties are unsuitable.

Important. When marking the placement of logs, it is tedious to take into account the dimensions of the plywood sheets.

The fact is that there must be logs under all joints. It is better to first draw on paper a diagram of the arrangement of plywood sheets; during calculations, both longitudinal and transverse joints should be taken into account. You can fix the plywood to the joists with nails or self-tapping screws.

And, in addition, it has good heat-protective characteristics, which makes it possible not to use it for floors. additional insulation. Do not forget to glue the joints of the sheets of technical cork with tape. Otherwise, they will shift during the work, which complicates the laying of the laminate and makes the work more “nervous”.

Prices for plywood sheets

plywood sheets

Methods for insulating floors along logs in a bathhouse

Floor insulation using joists - diagram

To insulate pilaf, two types of insulation can be used. None of them are ideal option. Why?

Let's start with mineral wool.

It has high performance characteristics in many respects: it holds heat well, it is easy to work with, and the thermal insulation layer has no cracks. But cotton wool also has a drawback - the material quickly absorbs moisture and releases it for a very long time. Prolonged exposure of wooden elements to direct contact with wet cotton wool significantly accelerates the appearance of rot and fungi. Wooden structures must be impregnated with antiseptics and used mechanical methods steam and water protection. Such construction activities are quite expensive.

The second insulation is polystyrene foam boards.

This material does not absorb moisture. The fact that there are comments about it regarding environmental friendliness is not critical for the premises in the bathhouse, no one is going to live in them. Foam plastic is “destroyed” by its lack of environmental friendliness and physical indicators, it is “destroyed” by rodents.

None of the manufacturers warn that mice, for unknown reasons, really like this material; they chew it with great pleasure and with great pleasure. high speed. No one has yet succeeded in completely getting rid of rodents in their summer cottage. We hope this information will help you decide optimal solution when choosing floor insulation material.

How to insulate floors along joists with mineral wool

You can take both rolled and pressed material. The only note is that if you take pressed mineral wool, then the dimensions of the sheets should be taken into account when placing the logs.

Nail thin slats or bars to the side planes of the logs; the subfloor will lie on them. To make it you can take unedged boards, pieces of lumber, remnants of plywood or OSB sheets. Mineral wool must be reliably protected from moisture penetration from below; the ground under the bathhouse will always have increased humidity levels.

For vapor protection, you can take any of existing materials, they all have excellent performance characteristics.

Lay mineral wool on the subfloor carefully, do not leave any gaps or gaps. The thickness of mineral wool cannot be greater than the height of the logs.

The upper surface of the insulation must be covered with waterproofing and only after that begin to work on the finishing floor covering.

One of the floor insulation options. The film is fastened with staples over basalt mineral wool

If it is possible to replace mineral wool with glass wool, take this chance immediately. Glass wool is much cheaper than the “branded” material, and in terms of its physical and operational properties it is in no way inferior to it.

Glass wool - insulating material

One of the disadvantages of glass wool is considered to be its “prickliness”. This is not a problem, work in canvas work gloves and nothing will “bite” you. For your information, fashionable mineral wool is made from rock basalt, which is the same glass, only with different impurities. Mineral wool “doesn’t bite” only because the diameter of the glass fibers is much smaller, they break very easily and cannot damage the skin. But there is much more fine glass dust, and this is harmful to the lungs.

Prices for mineral wool

mineral wool

In this option, the work is slightly simplified and cheaper. The subfloor is made in a similar way as in the case of insulation mineral wool. But you don’t have to do steam and water protection; this can significantly reduce the cost of the work. You will have to solve the problem with rodents yourself. Some suggest laying galvanized metal mesh with small cells on the subfloor, while others will ensure that rodents do not spoil all the foam. You will have to decide for yourself what to do.

Polystyrene foam can be cut perfectly with a special carpenter's knife. When cutting, make the sheets a few millimeters larger. The sheet will easily shrink, due to this the tightness of the fit to the joists will significantly increase. With proper cutting, the amount of unproductive material waste is reduced, and work is completed faster and with better quality.

Prices for foam plastic

Styrofoam

Video - How to cut foam with a knife

Scheme utility networks you should have before starting the construction of floors; they need to be taken into account when marking the locations of joists and laying insulation. Let's give a few practical advice for installation of engineering communications.

All connections must be made as securely as possible and very carefully. This applies to both sewer pipes, and electrical wiring.
Electrical cables must be laid in plastic or corrugated metal pipes. In fact, we do not recommend laying wiring under the floor; it is much more convenient to route it along the walls. Moreover, they will still be finished with clapboard or other materials, and under them you can hide all the networks without any problems.
For sewerage, it is necessary to provide for the most dangerous places in terms of blockages. Open pipelines in such places have special technological access; if the pipes become clogged, they can be easily cleared with their help. Most often, dirt accumulates in the knees and joints. Place them as close to the walls of the premises as possible. Moreover, the boards in such places must be parallel to the direction of the pipeline. This will make it possible to provide access to problem area after dismantling just one or two boards.

Communications under the floor

During installation sewer pipelines better to stock up on bandwidth, to be safe from clogging. The pipe path will be larger in diameter, although their total length will increase slightly. The main thing is to have confidence in long-term and reliable operation the entire system.

Video - Installation of subfloor

Video - Floors on the ground. How to do it right

The service life of both the rough and final coating depends on how well the base for the future floor is prepared. Many new technologies have appeared on the modern construction market, differing huge benefits, providing a lot of opportunities for implementing the most intricate design ideas. But the old, time-tested method, which uses floor joists, is still very popular. In this article we will look at what logs are, why they are so good and how to install them correctly wooden floor.

Logs are wooden or polymer bars various shapes and sizes located under the finishing coating. The main advantages of using this method:

increasing heat and sound insulation properties;
more uniform distribution of load on the base;
leveling the surface for a finishing layer;
the formation of a ventilated underground, allowing communication networks to be located in its space;
high strength (floors on logs can withstand up to five tons per square meter);
ease of installation;
relative cheapness of the project.

The logs can be laid both on an earthen base and on wooden or iron concrete floors buildings.

Logs are thoroughly dried wooden blocks, serving as the basis for a finished floor covering

Installation of joists over floors

Wooden floors

If the floors are wooden, then most often their beams are not very even, and when laying joists directly on them it is very difficult to achieve a flat horizontal surface. In this case, the logs should be attached to the sides of the beams.

The main advantage of this method is that you do not need to use pads to adjust the height of the joists. Fastening is carried out using partial screws, and their length must be at least 2.5 times longer than the width of the log, and their diameter must be at least 6 mm.

Tip: to avoid splitting the wood, before fastening it is recommended to drill a hole in the joists and beams with a diameter 2.5 mm less than the diameter of the screw.

If the beams are located at a large distance from each other, then it is necessary to lay the second syllable of the log perpendicular to the first, but at a closer distance. Another way to remedy this situation is to use thicker finishing boards.

Concrete floors

When laying joists on concrete floors, you need to take into account that in such a situation the entire floor structure will look a little different:

When laying floors on concrete, care must be taken to ensure waterproofing, otherwise the floors will constantly become damp.
Next are the heat and sound insulation layers.
Then you should definitely make a dry or cement screed.
And only after that the logs are laid, on which the finishing coating is spread.

For logs, you should not take boards shorter than two meters. If the selected length is still not enough, then the parts are joined end to end.

Important: when connecting lags to each other, you must ensure that the joints in adjacent rows are offset by at least half a meter relative to each other.

The logs are laid on the floor screed. If this is not possible, then the surface of the base must at least have waterproofing.

Before laying the logs, concrete floors must be waterproofed so that the wood does not attract moisture.

But on soft insulation flooring lags is strictly not recommended, in this case they will float, which will lead to the gradual destruction of the final finish. If heat and sound insulation allows installation with sheets of a certain width, then the logs on the base are positioned in such a way that the insulating material is located strictly between them.

Advice: if it is not possible to arrange the logs to fit the width of the roll insulation, then you should select such a distance between the logs so that the last cells can be filled with scraps with minimal waste of material.

Laying logs on an earthen base

If the floor on joists is located directly on the ground, then you first need to remove all the turf, scatter approximately 50 mm of gravel over the surface, compact it thoroughly and fill it with a five-centimeter layer of lean concrete. Next, we proceed as with a concrete base, that is, we put waterproofing, insulation and screed.

Tip: when laying the floor on an earthen base, the thermal insulation layer and screed can be replaced with polystyrene concrete.

A little higher we touched on the concept of “distance between lags”. I think many will be interested in how to correctly calculate this value, because in order to achieve optimal load distribution, the logs must be laid at the most equal distance from each other. Usually the distance between them ranges from 350-400 cm.

Distance between floor joists

Let's assume that the room in which the floor joists are being installed has a length of 8.5 meters. The door is in one of the short walls, and the window opposite it is in the far wall. We will place the logs perpendicular to the long side, and the finishing board at a right angle to the logs. This is done in order to finishing coat was located parallel to the light rays entering the room from the window.

Let the width of the bars we prepared for the logs be 0.09 m. Typically, the first and last logs must be 30 mm away from the walls. Let's take the number of lags as y, then their total width will be equal to 0.09*y. The average distance between the logs is 0.375 m and there will be y-1 such distances, then the total distance between all the bars will be 0.375 * (y-1). Knowing the recommended distance to the walls, 0.03*5=0.15, we obtain the equation:

0.15+0.375(y-1)+0.09y=8.5,

solving which we determine that we will need 18.96 lag. Since their number must be a whole number, we round to the nearest value. That is, for this room we need 19 logs. Now we find the sum of all distances between the lags:

8,5-(19*0,09)-0,06=6,73,

and since there are 19-1=18 such distances, we get the exact width between the joists

6.73/18=0.374, not 0.375 as we first assumed.

The surface on which it is planned to lay the floor on logs must be thoroughly cleaned and well primed.
All wooden parts must be dried and treated with an antiseptic, for example, bitumen.
Sound insulation can be made of slag or sand, as well as fiberboard.
The logs should be installed along the window, with a gap between them and the walls of no more than 30-40 mm.
After laying, the plane of the surface of the log is checked against the rule (long level) located across the beams. If there are no gaps between it and the beams, then the installation was done correctly. If they do exist, then the surface can be leveled by removing it or, conversely, adding sand under the lag.

After laying, the surface of the lag is checked using the rule (long level)

Promising adjustable joists

New technologies have also affected such an old method as installing floors using joists. Modern beams already have ready-made threaded holes, adding reliability to the connections.

Height change adjustable joists carried out by rotating special bolts

In addition, such logs can be adjusted by rotating special bolts, allowing you to quickly and easily special effort change their height. After completing the adjustment, the excess bolts are simply cut off.

Laying a wooden floor on joists

Experience shows that wood is practically ideal material for flooring.

A properly laid wooden floor has a long service life, it is beautiful, environmentally friendly and does not require complex maintenance. Let's consider the main advantages of such a foundation:

ease of leveling the floor surface;
elevated thermal insulation properties;
quick and easy installation;
efficiency;
good sound insulation;
the possibility of placing communication structures underneath.

If you use conifers tree, the result will be not only beautiful and durable coating, but also a wonderful healthy microclimate in the house. So,

What is needed to lay a wooden floor on joists?

perforator;
axe;
level;
saw or jigsaw;
claw hammer;
drill and screwdriver;
wrench 13-14;
logs 50x50mm;
floor board;
insulation;
hardware (10mm anchor bolts, 35, 50, 75mm self-tapping screws, 50 and 70mm nails).

The logs are laid at a pre-calculated distance from each other. soundproofing material. When laying, it is necessary to use a level to ensure that the surface is even. TO concrete base logs are attached with anchor bolts, to all others - with dowels.

Tip: length anchor bolt We calculate by adding 6 cm to the height of the log.

How to lay thermal insulation

In the gaps formed by adjacent joists, thermal insulation is laid, for example, polystyrene foam, isospan or basalt fiber. It is more convenient to use roll insulation. Expanded clay can also be used as a heat-insulating layer.

Insulation is laid on top of the waterproofing between the joists.

Finished flooring

The installation of a wooden floor along the joists begins from the corner of the room. We place the first row of boards with a tongue and groove to the wall, leaving a small gap between the wall and the boards of up to 10 mm, necessary to compensate for the deformation of the wood as a result of the change environment.

The next row is laid offset relative to the previous one by approximately two logs. A tight fit of the boards to each other is achieved by lightly tapping with a hammer on a piece of wood attached to the end of the adjacent board.

The boards are laid in such a way that each subsequent row is offset by approximately two joists

When attaching boards along the walls, it is allowed to place the screws on top, since their heads will still be masked by the baseboard, but in all subsequent rows the covering should be attached only to the bottom wall of the groove, driving the screw heads inside the board.

After laying all the boards, you can begin to close the expansion joints using plinths. In addition, this will protect the walls from contamination.

Secrets of correct laying of boards

You can begin laying wooden floors only after the joists have been completely leveled.
Boards are attached to each joist without exception.
The size of the boards should be selected so that the joints are in the middle of the joists and are perpendicular to the long side of the board.
To prevent the boards from splitting, holes for fasteners must be drilled in advance. For self-tapping screw we use thin drill, and for his hat - thicker.
Instead of a plinth, you can place a fillet - special profiled strips - to mask the gaps between the walls and the floor.
Holes for pipes must be drilled with a diameter 8-10 mm larger than the diameter of the pipe.

Tip: for greater reliability, before fastening with nails, it is better to tighten the boards together construction staples using a stapler.

How to level the floor in old houses

The base of the floor in old houses is almost never smooth and even. Differences in its height can reach 20 cm and it is very difficult to adjust such a surface. And application concrete screed not always permissible, since not all beams in old housing are able to withstand heavy loads. This is where the use of adjustable joists will help. Let's take a closer look at the installation process:

Bolts are screwed into special holes in the joists, with at least five holes required for every two meters of beams.
We lay out the logs taking into account the pre-calculated distance between them.
Holes are drilled in the ceilings for dowel-nails, making sure to bring the drill to the holes for the rack bolts.
We level the logs and hammer in the dowel nails, cutting off the protruding parts of the post bolts.
We lay the wooden floor on joists, that is, the finishing coating.

Floor finishing

But laying the floor on joists is far from the end of the floor installation. Next you need to get rid of roughness and altitude differences. To do this, it is convenient to use a small grinding or sanding machine. We start cycling with a large one sandpaper, quickly removing all irregularities, and then polishing the surface using fine-grained sandpaper.

oil impregnation;
parquet varnish;
wax mastic.

How to get rid of a squeak

First you need to determine the places where the floor wobbles and sag greatly. Now here you need to remove the loose nails and screw the screws in their place. Using old nails, you can easily determine the location of the joists under the finished base; these are the places that should be reinforced with additional self-tapping screws so that the head completely fits into the wood. After the squeak is eliminated, all these places are puttied, and the floor covering is completely renewed.

Video: visual information about floors using joists

We hope that our article will help you decide on the type of flooring and handle the wood flooring yourself.