Do I need to screw the joists to the concrete floor? Laying joists on a concrete floor

Wooden floors are considered the best finishing option. This is an environmentally friendly and warm material. But installation of such floors on concrete base associated with certain difficulties. In order to perform this process technologically correctly, it is necessary to first attach the lag to concrete floor. It is not recommended to lay wooden floors directly on a concrete screed. Using lag as additional elements will provide floor ventilation and optimize heat exchange in the apartment. Accordingly, the floor covering will last much longer. Fastening the structure to a concrete floor is a simple process and does not require special knowledge and skills. We will introduce you to all the intricacies of performing these works.

Preparation of materials and tools

Before starting work, you need to stock up on everything you need. Considering that you will have to work with wood and concrete, the list necessary tools will be as follows:

• pencil;
• building level;
• roulette;
• hammer drill;
• tools for working with wood (plane, hacksaw or a circular saw);
• screwdriver or set of screwdrivers;
• fasteners(usually these are self-tapping screws, dowels and anchor bolts).

Having prepared the tools, you can go to the nearest construction market to buy materials. Typically, lumber sellers, pursuing personal gain, advise purchasing expensive types of wood, citing the reliability and long service life of the material. There is no need to fall for this trick. Spruce, fir and pine may well be suitable for your purposes. Wood grades of category B or BC are quite suitable; the moisture content of the material should not exceed 18-20%. Wherein appearance, color and even evenness of parts do not play a big role. The only thing you should pay attention to is the absence of mold and traces of the work of the bark beetle.

The cross section of the lag depends on the thickness flooring and insulation. Experts do not recommend using timber with a cross-section of less than 20 millimeters as lag.

Installation process

It’s worth clarifying right away that using floor joists is only advisable in apartments with high ceilings. This floor installation technology “steals” the height of the premises quite significantly. So, the installation of the logs occurs according to the following scheme:

• It is recommended to level the screed or concrete base. Otherwise, the elements will not be in the same horizontal plane. Accordingly, they will need to be leveled by placing plates. This can lead to the floors in the apartment creaking.
• You need to lay a layer of waterproofing on the base, or treat the concrete with a special mastic. In the first case, you should avoid using soft materials. Over time, they will sag, and the floor will no longer be reliable and solid. For a waterproofing layer, roofing felt or polyethylene film is perfect.
• The logs are treated with an antiseptic compound and cut according to the size of the room.
• The installation process begins with installing joists at two opposite walls. These elements are aligned using building level and are immediately fixed to the concrete floor. Then a string is stretched between the installed joists. It will serve as a guide for the installation of other elements.

• The remaining logs are laid. The distance between the elements directly depends on the thickness of the future floor covering.
• Insulation is poured between the joists. For this, ecowool or rolled materials can be used. In the second case, you need to mount the material as tightly as possible without leaving gaps between the layers.
• A layer of vapor barrier is laid down. This necessary condition to protect the insulation from external influences. The vapor barrier can be attached using a stapler; the joints must be taped.
• You can lay a layer of plywood. This will serve as the basis for installing the flooring.

Distance between structural elements

In order for floors to last a long time, you must strictly observe the spacing between laid parts. To do this, you can use the table.

When laying a plywood base on joists, the distance between the elements can be increased.

Methods for installing logs

There are four ways to install joists on a concrete base. After reviewing the material provided, you can choose the best option for you.

Self-tapping screws

This fastening scheme is considered the simplest and fastest. It looks like this: the logs are laid in place and drilled through. Please note that the drill must go through the wood and go deep into concrete covering. A dowel is driven into the hole and a self-tapping screw is screwed in.

The recommended distance between fasteners can vary from 40 to 80 centimeters. The length of the fastener depends on the thickness of the log. Please note that the self-tapping screw must penetrate the concrete no less than 50 mm. For better adhesion of the lag to the surface, it is recommended to use self-tapping screws with threads that do not reach the head.

Anchors

This method is used not only for fastening elements, but also to give the structure additional strength. It is quite problematic to pull out an anchor from a concrete base, so difficulties may arise when dismantling such a structure. Anchors are installed, like self-tapping screws, by drilling through holes. A locking element is inserted into the concrete, into which the bolt itself is screwed through the joist. In order for the bolt head to “sink” into the wood, the holes must first be countersinked.

Metal corner

Another installation method wooden elements on a concrete base. To do this you will need a galvanized metal corner. The installation process looks like this: the corner is attached to the joist using a self-tapping screw (the fastener must extend into the wood at least 3 cm). Then the corner is attached to the concrete surface with a self-tapping screw through a dowel.

Adjustable joists

This is the most expensive design, which significantly simplifies the alignment of elements in the horizontal plane. It looks like this: plastic racks are built into the wooden elements, which, in turn, are attached to the base of the floor. Alignment occurs using an adjusting bolt. Using this design will allow you to complete the work without first leveling the screed.

mr-build.ru

Attaching joists to a concrete floor - the secrets of professionals - Floor School

Today, there is a wide variety of possibilities for arranging a concrete foundation in private houses or city apartments. During the work you can use all kinds of flooring, insulation, insulating materials, you can align concrete surface self-leveling solution and use a “warm floor” system.

Laying joists on a concrete floor does not lose its relevance. This method of arrangement is especially in demand when constructing private houses, in which the ceiling height allows all the necessary operations to be carried out. One of the advantages this method is the possibility of using relatively inexpensive insulation materials.

Wooden logs on concrete base.

In this article we will talk about how to attach joists to a concrete floor.

About the features of fastening lags

When attaching one or another building material to a concrete base, they can be used various instruments and fasteners. Fastening wooden logs is comparatively simple. The work is carried out in several stages.

Selecting materials and tools

Today, one of the most popular methods of laying joists does not involve attaching them to the floor. With this option, structural rigidity is achieved due to the fact that the joists are fastened together using boards or other material. The method is quite reliable, but there is still a high risk of shifting the floor covering.

Therefore it is best to use traditional version, which involves fastening to the base using anchors or self-tapping screws.

Choosing lags

Pine timber.

When choosing a log you need to pay attention to the following criteria:

• The type of wood that can play a key role in the strength of the foundation.
• The price of the purchased material. It is best to use inexpensive coniferous wood (fir, pine, spruce) when carrying out this work. In this case, grade 3 wood will also work. The main thing is that the humidity level does not exceed 20%.
• Dimensions of beams in cross section.

Advice! The choice of section sizes depends on what type of insulation you will lay between the joists. In addition, last but not least, you should think about the height of the ceilings.

If the height is small, you should not raise the floors too much, since this way you will compress the interior space of the room.

Choosing tools

To install the logs, you will need tools designed for wood processing and for drilling concrete:

• Hammer.
• Anchors (such fastenings are selected depending on the cross-section of the beam).
• Self-tapping screws 6 mm in diameter, the length of which depends on the size of the beams. They must come complete with polypropylene dowels.
• Some carpentry tools: plane, hacksaw, circular saw, etc.

Many home craftsmen are interested in how to attach joists to a concrete floor. The choice between self-tapping screws with anchor fastenings should be based on the planned financial costs.

Anchors are distinguished by reliability and durability.

The first option is more economical, the second is much more reliable. In practice, in most cases, a dowel fastening is sufficient; in addition, cheap self-tapping screws should be screwed in at much smaller increments.

The main advantage of anchor fastenings is that they not only fix the position of the beams, but also press them to the base. This is very important if the finished flooring is quite massive and is subject to frequent mechanical stress.

Don't forget about the waterproofing agent. It must be laid on the concrete floor before the logs are installed.

Tip! You can use roofing felt or construction polyethylene as waterproofing.

Also, the wood for the floor should be treated with antiseptic properties and primed. Treatment is carried out before installing the logs.

Advice! If the work will be carried out on an uneven concrete base, then you will need supports for the beams.

For these purposes, you can use boards, plywood, and chipboard for the floor.

The photo shows the use of substrates on uneven substrates.

Features of installation

After all materials and tools are prepared, you can proceed directly to installation.

The instructions provide several steps:

1. We lay roofing felt on the concrete floor. The joints between the sheets must be glued using construction tape.
2. We distribute the logs along the base. We lay two of them along opposite walls. The rest should be placed with a certain step, taking into account the rigidity and density of the material laid on top of the logs. Accordingly, the stiffer the material, the smaller the step. The average parameters are 40-80 cm.
3. If the length of the room exceeds the length of the beams, then they are laid joint to joint. If high joists are used, or a high load is expected on the floors, it is necessary to make end cuts to connect the elements.
4. Having laid two logs along the walls, we set their height using a level.
5. We stretch a cord between the outer lags along which the remaining beams should be laid.
6. We drill holes in the block and the base.
7. We place an anchor spacer or dowel into the hole in the floor.
8. We screw in the bolts or screws. There are two or three anchors per beam. Self-tapping screws are screwed in in increments of 60 to 80 cm.

Attaching the beams to the base.

If necessary, prepared pieces of timber or boards must be placed under the logs.

We lay insulation between the joists.

We install a vapor barrier membrane on top of the insulation.

The next layer is the floor covering of the apartment or house.

Conclusion

As you can see, installing the floor on joists with your own hands is much easier than it might seem at first glance. It is quite possible to create a solid foundation if you listen to the advice of experts. The video in this article will help you learn even more useful things.

We sincerely hope that the work we have done will bring you practical benefit. Good luck in the repair!

shkolapola.ru

How to attach joists to a concrete floor?

• • Apartment floor repair
• How to prepare the bars?
• Laying support beams
• Installation of adjustable joists

New technologies for laying floors have not been able to displace logs from construction, which are used as a base for wooden floors. The only drawback of logs is that after their installation the height of the room is significantly reduced, so it is more advisable to install logs in houses and apartments with high ceilings.

Scheme of laying support beams on a concrete base.

How the lags are attached to a concrete floor will be described below, but for now it’s worth talking about the advantages of such a flooring device over others. In the space underneath you can place electrical and other cables, as well as pipelines, for the installation of which you do not have to cut walls. In addition, floors on joists turn out to be much warmer not only because they are made of wood, but also because of the ability to lay insulation between the base beams. In addition, additional sound insulation of the room is provided. It is worth adding that the concrete base will be the most reliable support for lathing wooden floors.

Preparing the base before laying joists

Most residential buildings have concrete floors. To lay the logs, they only need to be properly prepared. Of course, such work is quite labor-intensive, but for the long life of the wooden floor it is certainly worth the effort.

Pouring the foundation for joists in a country house

Scheme of pouring the base for the logs.

For those who build houses on suburban areas, we can advise not to lay the logs on the ground, but to arrange them on concrete, because even compacted soil does not have the same strength as a concrete floor. The easiest way to pour a concrete base is around the perimeter of the strip foundation.

Concrete is poured onto a compacted and horizontally leveled bedding made of sand, crushed stone or AGS, the surface of which must be carefully smoothed to prevent breakthroughs of the waterproofing film laid on it. The ceiling must be reinforced. To do this, reinforcement or rods are placed on top of the waterproofing. There must be a gap between the reinforcing lattice and the bedding so that after pouring the concrete, the reinforcement will be thicker. After the concrete has completely hardened, which lasts about a month, a leveling screed is poured.

Apartment floor repair

Those who are going to lay joists in apartments where concrete floors were installed during the construction of houses should not “relax” either. More often than not, it turns out that foundation repairs are inevitable. True, in some cases it is possible to lay joists on a concrete floor without precisely leveling it (one of the sections will be devoted to this method), but it is imperative to bring the ceiling into proper shape.

The first priority in preparatory activities– remove old flooring. After this, the old screed is removed. Often it ends up in a dilapidated state. To remove it you will need:

Screed repair tools.

• perforator;
• construction hammer;
• shovel.

Hammer or crowbar old screed is removed to the permanent foundation. Noticeable protrusions also chip off it. After cleaning construction waste Cracks and depressions in the ceiling are sealed with mortar. After this, the base should be thoroughly dried. In the future, all operations both in apartments and in houses under construction are performed in the same way.

Preparing the base for leveling

An antiseptic composition and primer are applied to the dried base. After this, the overlap is processed bitumen mastic in 2 layers. The mastic is also applied to the walls to a height equal to the thickness of the future screed. Please note that the smoother you make the screed, the easier it will be for you to install the logs, which all you have to do is lay them on an ideal horizontal surface. Therefore, create a plane before filling it. This operation is simple, but requires patience and precision in marking. To do this you need:

• painting cord;
• hydraulic level;
• dowel-nails;
• roulette;
• synthetic threads;
• gypsum;
• beacon profiles.

Scheme for placing beacons.

Make a chalk mark on one of the walls (near the corner). Apply it at any height. Using a level, place a point at the opposite end of the wall. Stretch a cord rubbed with chalk between the marks and, pulling it back, beat off a horizontal line on the wall. Make lines on the other walls in the same way. Using a tape measure, determine the point on the floor furthest from the chalk line. Place a mark opposite this point on the wall, move up 2-3 cm from it and place another mark. This will be the level of the future screed.

Measure the distance between it and the chalk line and place marks along it near the corners of the walls. Pulling the cord between them, beat off horizontal lines. Along them, drive 3-4 dowel nails into each wall. Pull the thread between the opposite surfaces.

The screed plane is ready. Now you can place beacons under it. They head from the far wall towards the entrance. The extreme profiles are located 15 cm from the walls. The distance between the beacons should be 20 cm less than the length of the rule. The profiles are attached to the base with gypsum cones, the pitch of which is 30 cm. After the gypsum has hardened, the solution is poured and leveled with the rule.

How to prepare the bars?

While the screed is drying, start preparing the lag. It is best to use coniferous wood for them. When purchasing, choose the straightest beams. When calculating their number, you need to take into account:

• the distance between the walls of the room (it is better to avoid laying composite logs);
• the thickness of the floor covering, on which the distance between the beams depends.

The table shows the dependence of the floor joist pitch on its thickness.

The following table provides data on the relationship between the distance between the joists and the thickness of the plywood or OSB floor.

It should be noted that plywood and OSB are superior in strength to solid wood materials.

After purchasing floor joists, they must be thoroughly dried.

Drying of the beams is carried out in a closed area sun rays indoors.

Figure 1. Diagram of an adjustable stand with sound insulation.

Drying time takes 10-12 days. The logs are laid at a certain distance from each other, and transverse bars are laid between their rows (every 0.7-1 m). Gradual drying of wood does not guarantee that all logs will retain their original shape, so they should be purchased with some reserve.

The screed froze and the joists dried out. You can start installing them. In front of it, waterproofing made of polyethylene or bitumen is laid on the floor. The beams are treated with antiseptics and fire retardants. After this, their installation begins.

Laying support beams

There is a way in which the beams are attached to each other, but are not attached to the base. A flat horizontal plane is ideal for this technology. First, the beams are laid out around the perimeter of the room, but not close to the walls, but at a distance of 2-3 cm from them. They are tightened with self-tapping screws into a box. After this, the remaining sheathing beams are laid. They are directed along the short walls of the room. Self-tapping screws are also used to tighten the sheathing. The correct installation of the joists, even on a level base, must be checked with a building level.

There is another method for installing lags. It eliminates the possibility of the support sheathing moving during operation of the floor. The beams are attached to the base with self-tapping screws screwed into dowels or anchors. Fasteners made from anchor bolts (screws) with a cross-section of 10 mm seem to be more reliable.

Its pitch can be 1 m. Fastening with self-tapping screws with a diameter of 6 mm is carried out every 0.5 m. Anchors can be screwed into concrete through holes drilled in the beams. The depth of their immersion in the screed should be 5-7 cm. The depth of screwing in the screws should not be less than 5 cm. When attaching the logs with self-tapping screws, use metal corners. It is necessary to add that between the beams and the screed you need to put gaskets of the same thickness from pieces of roofing felt or linoleum (they need to be placed in the places where the beams are attached).

Installation of adjustable joists

Now we can talk about the construction of concrete lags on adjustable racks. In Fig. Figure 1 shows one of the varieties of such devices. They are used on uneven bases, and the correct installation of the beams horizontally is achieved by adjusting the height of the supports in the range from 10 to 25 cm. This technology is becoming more and more common. It is believed that it will soon replace the installation of joists on a leveling screed, but the price of components for installing adjustable joists is still high.

When laying beams using this method, you should avoid using logs made up of 2 or more elements in the sheathing. If such beams are still used, then there must be support points under their ends. In addition, the spread of the joints of composite beams in adjacent rows should not be less than 0.5 m. It is allowed for the joints to be located opposite each other across the row. To facilitate the installation of adjustable joists, it is best to build a horizontal plane, the same as before pouring the leveling screed.

moyagostinaya.ru

How to attach joists to a concrete floor yourself?

No modern material will not fully replace traditional wooden floor. True, its installation is associated with some difficulties (the need correct selection wood for logs, they are strictly horizontal installation, careful adjustment of flooring boards), however wooden floor There is still no alternative in terms of environmental friendliness.

Wooden floors have always been highly valued. It is natural, attractive and safe.

It would seem that floorboards can be laid directly on a leveled screed, but logs are necessary to sufficiently ensure normal floor ventilation and the most optimal heat exchange in the room. Of course, the styling is perfect level screed will simplify the task of installing floor joists, so the very first preparatory work When installing a wooden floor, there should be maximum leveling of the base.

Required materials, tools and fasteners

Regarding the question of how to attach logs, it should be said that not every type of wood is suitable for their manufacture. The best material for them are coniferous trees: spruce, fir, pine and larch. As a rule, the beams are made of material with a cross-section in which the aspect ratio is 1:1.5. In addition, before you start attaching the logs, boards and beams must be thoroughly dried. The wood moisture content should not exceed 20%. It should be noted that installing wooden floors is only advisable in rooms with high ceilings.

For high-quality fastening of logs to a concrete base, a thorough approach to the selection of tools and fasteners is required. It is mandatory to use:

To install the logs you will need a hacksaw, a building level, a screwdriver, self-tapping screws, a construction pencil, etc.

• tools for wood processing (plane, circular saw or hacksaw, drill, etc.);
• screwdriver or screwdrivers;
• hammer drill (it’s good if you have a universal tool that can chisel, drill, and screw);
• self-tapping screws with a cross-section of 6 mm with plastic dowels (the plugs should be driven into the concrete by 6-8 mm, and the length of the fastener depends on the thickness of the beams) or anchor screws, whose dimensions depend to the same extent on the cross-section of the beam.

The choice of fasteners depends on your preferences and the thickness of the wallet, but it must be said that an anchor fastening is much more reliable than a dowel fastening, since the shank of the anchor, when screwed into the concrete body, expands its coupling and tightly fixes the fastener. However, it is often enough to use polypropylene dowels with self-tapping screws to attach floor joists, since most coatings will not have to experience extreme mechanical stress.

To install waterproofing you will need roofing felt.

In addition to the listed tools and fasteners, to install the log you need to prepare:

• waterproofing material (roofing felt and similar rolled bituminous materials);
• primer mixtures for processing screeds and wood;
• antiseptic compounds (you can always pick up multifunctional products in the store, which will significantly speed up the process of processing the beams).

You should stock up on pieces of plywood, chipboard or wood, which may be needed as pads under the joists to the floor to level the plane.

Operating procedure

So, the tools and Consumables prepared. You can start attaching the logs. The work is carried out in the following order:

Scheme of laying lags on a concrete base.

1. Make sure that concrete screed dry, and treat it with a primer.
2. Place waterproofing on the screed. Its adjacent sheets should be laid with an overlap of 10 cm.
3. Glue the edges of the vapor barrier tapes with bitumen compound or tape (depending on the material of the water-repellent membrane).
4. Treat the bars with an antiseptic.
5. Cut the joists according to the size of the room and distribute them over the floor surface. It is advisable that only 1 beam is used for each log. Joints are allowed when large sizes rooms when the timber is not long enough. The location of the joints on adjacent beams should not be the same. They must be spaced apart from each other by at least 0.5 m. There must be support under the joints.
6. Place the 2 outer logs against opposite walls. Place the remaining bars perpendicular to them. The distance between adjacent joists depends on the thickness of the flooring. The stride range ranges from 40 to 100 cm (more on this below).
7. Secure the end joists. Using a hydraulic level and a beating cord, install the end beams. Drill holes in them and in the concrete base, insert fasteners and fix the logs in the concrete. The fastening step with self-tapping screws is from 50 to 80 cm, and the anchor screws are screwed in every 1 m.
8. Attach to the floor cross beams. For better orientation, stretch a cord between the outer beams.

It is advisable that there are no pads under the beams, but if the screed is uneven, you cannot do without their use. Make sure that the pads fit snugly into the space between the timber and the screed. If there is a bulge under the joist on the concrete base, lightly trim the edge of the beam adjacent to this place with a plane or chisel.

Only by performing these procedures will the floor not creak under your feet in the future.

Now let's return to the question of the step between the lags. Its dependence on the thickness of the flooring boards is as follows:

The distance between floor joists depends on the thickness of the floor board.

• floor thickness 2 cm – distance between joists is 30 cm;
• for a 2.5 cm board, the step is 40 cm;
• for 3-centimeter boards, the distance between the beams will be 0.5 m;
• 35 mm requires 60 cm pitch;
• 40 mm boards are placed on logs, the distance between which is 0.7 m;
• for 45 mm flooring, a step of 80 cm is provided;
• under floorboards 5 cm thick, logs are attached at a distance of 1 m from each other.

Under a plywood floor, the distance between the joists is calculated slightly differently. A pitch of 40 cm is sufficient for laying a 15 or 18 mm covering, and for 22 mm plywood a distance between the beams of 60 cm is suitable.

After installing the beams, you can fill expanded clay between them or lay another heat insulator. While the flooring is not laid, you can lay some communication lines. Before installing the floor on the joists, it is advisable to lay a vapor barrier film.

Laying beams on the ground

Scheme of laying logs on the ground.

There are cases when the beams under the floor have to be laid not on a concrete base, but on the ground. To attach the logs in this way, it is necessary to clear the soil from the top layer and compact it thoroughly. It will be even better if the surface is covered with crushed stone. The backfill layer can be up to 5 cm. After leveling the crushed stone, waterproofing is laid on the ground.

On the walls of the building it is necessary to mark the horizon along which the logs will be installed. Marks are made using a laser or water level and a tapping cord. First of all, the beams are installed along 4 walls. The logs are placed on stands made of bricks, boards or other materials. All wood products must be treated with antiseptic compounds, and roofing material must be laid between the joists and supports. There should be a wooden spacer between the brick stand and the floorboard. Its thickness cannot be less than 25 mm. The distance between the outer beams and the walls should be at least 2 cm. Threads can be stretched between the opposite walls, which will serve as guides for installing the beams.

Lag fastening diagram.

Now the remaining logs are attached. Their location should be perpendicular to the direction of the floorboards. It is recommended to lay the support beams transverse to the direction of lighting through the window opening. The pitch between the joists when installed on the ground depends to the same extent on the thickness of the flooring as when mounted on concrete. The cross-section of the beam must correspond to the distance between the walls of the room (span):

• for a 2-meter span, timber 110 x 60 mm is used;
• if the walls are located 3 m from each other, 150 x 80 mm beams are used;
• 4 m – 180 x 100 mm;
• 5 m – 200 x 150 mm;
• 6 m – 220 x 180 mm.

The use of logs shorter than the span when installing them on the ground is extremely undesirable.

Adjustable joists

We also need to talk about modern means adjusting the lag level. Manufacturers produce special racks that can change the height of the beams from 10 to 25 cm. Such devices are very useful when installing a wooden floor on an uneven base. They are threaded posts attached to the ceiling with dowels and nails. Changing the height of the beam is carried out by screwing or unscrewing a threaded rod, fixed in the desired position with a lock nut. Supports under the beam can be inserted into holes drilled in its body. They are often equipped with corners with holes through which self-tapping screws are screwed into the joists.

http://youtu.be/yJqvB4l7O1s

Despite the apparent complexity, installing joists is not that difficult. If you do not violate the installation technology, the wooden floor will serve for many years without the slightest creaking or sagging of the floorboards.

Wooden logs are required to ensure natural ventilation underground space and better heat retention in rooms. Thanks to the use of logs, the floor covering can last much longer. However, among people who do not have much experience in construction, you can often hear the question: is it necessary to attach joists to a concrete floor? Experienced craftsmen know that for a truly durable flooring that does not change its geometry under load, and for its long service life, it is imperative to correctly fix the logs on any supporting structure, including on a concrete screed.

Now that it is clear whether it is necessary to attach the joists to the concrete floor, it is worth noting that this task is not difficult, does not require special skills and knowledge, and, therefore, can be done by any home craftsman.

• Materials and tools
  • Fasteners
  • Tips for choosing lags
  • Tools
• Methods for installing joists on a concrete floor
  • Fastening the log to a metal corner
  • Attaching the joists to concrete pillars
• Step-by-step instructions for attaching joists to concrete with your own hands
• Step between joists

Materials and tools

Fasteners

The question of how to secure joists to a concrete floor has different answers: simple or adjustable designs. The latter use special screws, by tightening which the logs can be leveled. In addition, the choice of fasteners and fastening methods depends on what kind of joists are used.

Most often, the lags are fastened to the concrete floor with metal anchors or self-tapping screws with polypropylene dowels, the dimensions of which are selected depending on the cross-section of the selected beam for the lags.

The choice between anchor nails or self-tapping screws is determined by the following:

• Self-tapping screws are cheaper, of course, but anchors are more reliable. In practice, fastening with self-tapping screws is almost always sufficient.
• The advantage of anchors is that in addition to fixing the beams, they tightly press the logs to the base. This becomes especially important when the finishing coating is quite heavy and is regularly exposed to mechanical stress - this must be taken into account when choosing the method of how to properly attach the joists to the concrete floor.

At modern technologies the logs under the wooden floor could not be secured at all, however, such a solution would greatly increase the likelihood of the floor covering being skewed or the logs moving from their original location. Therefore, when it comes to fastening lags, it is best to rely on old methods that have been time-tested more than once.

However, fastening may not help if low-quality or unsuitable lumber or incorrect fasteners are chosen for the work.

When choosing logs for a concrete floor, you need to pay attention to the following points:

• type of wood;
• type of lumber;
• length and section;
• price.

For reasons economic feasibility You shouldn’t take expensive wood, because spruce, fir or pine are correct processing can last no less. The appearance of the material is not particularly important, however, you need to sweep away specimens eaten away by grinders or blackened by mold. Evenness of tone and correct geometry of the lag are of less importance. For this work, grades B and BC with a humidity not exceeding 20% ​​are suitable. As is customary to work with lumber, they should be stored in a dry room for some time so that they equalize the humidity with the surrounding atmosphere.

Before attaching the logs to the concrete floor, all wooden elements must be thoroughly impregnated with an antiseptic.

Tools

Since the task is how to lay logs on a concrete floor, you will have to use the following tools in your work:

• Drill and hammer drill.
• Carpentry tools: circular saw, hacksaw, plane.

In addition, you will have to spend money on waterproofing, which must be spread over the entire surface of the concrete. When calculating the amount of material, you need to add another 10-15 cm overlap to the floor area.

Methods for installing joists on a concrete floor

Methods for attaching joists to a concrete floor come down to four main options, after familiarizing yourself with which, any master can choose the most suitable one for himself.

This the simplest way fastening the lag, but, unfortunately, it is not suitable in every situation.

1. First, you need to drill holes in the timber to match the diameter of the plastic dowel, and use a hammer drill to make a counter hole in the concrete.
2. Then the dowels are driven in with a hammer, after which self-tapping screws are screwed into them or dowel-nails are driven deep into the ceiling.
3. The head of the screw should sink a few centimeters into the hole.

People often ask, what step of attaching the joists to the concrete floor is better? There is no strict standard here - the step can vary from 40 cm to 80 cm, but on average you can safely focus on half a meter.

The logs will hold securely enough only when there is a small gap between the base and the beam. This should definitely be taken into account by those who want to know how to properly lay joists on a concrete floor.

Anchors, unlike self-tapping screws, not only rigidly fix the logs, but also attract them to the concrete surface. Thanks to this installation, wooden beams will be held more securely, which is why most craftsmen prefer to use anchors. In addition, this powerful fastener will restrain the deformation of the wood to a certain extent, especially if it has not been sufficiently dried beforehand. But it is much more difficult to pull an anchor out of a concrete base than to drive it in, so workers will have to spend a lot of effort during dismantling.

Be that as it may, when using anchors, the floor covering will not swell, but it may sag. To avoid the latter, it is necessary to install gaskets more often.

1. Installation of logs on a concrete floor here begins with drilling through holes in the beam.
2. Then, opposite each of them, counter holes are made in the concrete.
3. After that anchor bolt inserted into both holes and tightened with a spanner or open-end wrench. It is important not to overtighten the bolt, otherwise it will bend the beam, especially when there is a gap in this place. Then and on finishing field there will be a depression here.

Before installing the anchor, you need to drill a hole in the beam larger diameter so that the bolt head fits there.

The anchors should be spaced at intervals of 60-100 cm, and their length should be sufficient for them to penetrate approximately 6 cm into the concrete. Most often, anchors with a diameter of 10 mm are used. Typically one joist is held in place by 4-5 anchors.

Video about attaching joists to a concrete floor with anchors:

Fastening the log to a metal corner

It becomes inconvenient to work with logs 10 or more centimeters high. To fasten them, it is better to use steel corners, which will touch the joist with one shelf and the concrete base with the other. In this case, fixation is carried out: to the concrete - with dowel-nails, and to the timber - with self-tapping screws. In this case, the main load should fall on the gaskets, and not on the fastening elements, because the corners should only fix the position of the beam.

In order for the lag to be better bonded to the surface, you need to use self-tapping screws whose threads do not reach the head.

You can also attach wooden elements to a concrete base using a galvanized steel corner. The installation process is as follows:

1. Attach the corner to the joist using self-tapping screws, which should go at least 30 mm into the wood.
2. Attach the corner to the concrete base using dowels.

Video on how to secure joists to a concrete floor with corners:

There is another option for attaching joists to a concrete floor. For this, a rectangular stand is used, which is attached to the base with four dowels. In the middle of this stand there is a pin that pierces the beam through and through.

By rotating the nut located under the beam, you can accurately set its height, and use the upper nut to fix the element in the required position.

This system is not that difficult to install; it is attached to the floor with dowels, and you will need to make a hole in the joist for a pin. The frequency of installation of stands under it depends on the cross-section of the log; however, in any case, it is not recommended to make an interval of more than 1 meter. This option of attaching the log to a concrete base, although recognized as optimal, however, due to its high cost, has not become very popular.

After fixing the logs, a subfloor made of boards, OSB or similar materials. If the work is done efficiently, the appearance of the finished floor can be impeccable.

Attaching joists to concrete pillars

Logs are attached to concrete pillars in the same way. The same fasteners are used here, but intended for poles.

1. The pillars need to be waterproofed in advance by coating them with simple bitumen or bitumen mastic. The upper cut of the pillars can be waterproofed by placing pieces of roofing material pre-cut according to its configuration on it.
2. Also, in advance, you need to make holes in the bases of the pillars and in the timber into which to drive a dowel or anchor spacer.
3. The beam is attached to the post with a self-tapping screw, the length of which is 2-3 times the width of the spacer.
4. The timber can also be attached with special metal plates equipped with screws. For this purpose, they are screwed to the base of the posts with dowel nails, and a through hole is drilled in the joist, into which you will then need to insert a screw and screw the joist to the top of the posts. Thanks to this, the lag will hold tighter.

Step-by-step instructions for attaching joists to concrete with your own hands

Attach to concrete floor wooden joists It's not difficult even on your own. There are several mounting options, and below are the steps of one of the standard methods.

1. Lay waterproofing (roofing felt or simple PVC film) on the concrete base. The joints between the pieces must be secured with special tape.

1. Next, you need to lay out the logs along the floor in a certain step. This step will depend on the material from which the finishing deck will be made: when using tongue and groove boards 25x100 mm logs can be laid with a spacing of 70-80 cm, but for other materials the spacing will need to be reduced to 40 cm.
2. If the length of the material is not enough to cover the entire room, then the elements can be joined using an iron angle or by making cuts that form a connection into a root tenon.
3. Before installing the joists on the concrete floor, you need to take care of the outermost joists that will be located near the walls. They must be laid level, clearly leveling their height by placing them under the beams wooden planks or pieces of plywood. It is most convenient to use a laser level. When the outermost logs are fixed, a nylon thread is stretched between them, which will serve as a guide when installing the remaining logs.
4. To attach timber to a concrete floor, you need to make holes in both. You need to drive a dowel or steel anchor spacer into the hole in the concrete. Each joist must be fixed with at least four anchors, and the screws must be placed 40-60 cm from each other.

1. You need to prepare levelers for the joists in advance - cut chipboard or plywood into even strips. With the help of these elements, the joist structure is fixed in a level position (pieces of plywood are simply placed under the joists if you need to raise them) so that the finishing coating on it does not creak or move.

1. If, on the contrary, there are bulges in the concrete base, then you will have to level the lag not by placing plywood, but by selecting part of the material from below using a plane.
2. When all the logs are installed in their places, thermal insulation should be laid between them, for example, expanded clay.

1. Before covering with the topcoat, you should think about laying the necessary communications. It is also advisable to use a vapor barrier layer.

Step between joists

How to properly lay joists on a concrete floor if different materials will be used for the finishing coating? Below is the relationship between the thickness of the floor boards and the distance between the joists:

• with a board thickness of 20 mm, there should be a distance of 20 cm between the logs;
• for boards 25 mm thick, a step of 50 cm will be required;
• for 25 mm – 60 cm;
• for 40 mm – 70 cm;
• for 45 mm – 80 cm;
• for 50 mm – 100 cm.

If the floor is plywood, then the step between the joists is determined differently:

• with a plywood thickness of 15-18 mm, a lag pitch of 40 cm is required;
• at 22 mm – 60 cm.

Which method do you prefer to attach joists to a concrete floor, and why? Share your opinion or experience in the comments.

Tsugunov Anton Valerievich

Reading time: 4 minutes

Preparation of materials and tools

Before starting work, you need to stock up on everything you need. Considering that you will have to work with wood and concrete, the list of necessary tools will be as follows:

• pencil;
• building level;
• roulette;
• hammer drill;
• tools for working with wood (plane, hacksaw or circular saw);
• screwdriver or set of screwdrivers;
• fastening elements (usually self-tapping screws, dowels and anchor bolts).

Having prepared the tools, you can go to the nearest construction market to buy materials. Typically, lumber sellers, pursuing personal gain, advise purchasing expensive types of wood, citing the reliability and long service life of the material. There is no need to fall for this trick. Spruce, fir and pine may well be suitable for your purposes. Wood grades of category B or BC are quite suitable; the moisture content of the material should not exceed 18-20%. In this case, the appearance, color and even evenness of the parts do not play a big role. The only thing you should pay attention to is the absence of mold and traces of the work of the bark beetle.

The cross-section of the lag depends on the thickness of the floor covering and insulation. Experts do not recommend using timber with a cross-section of less than 20 millimeters as lag.

Installation process

It’s worth clarifying right away that using floor joists is only advisable in apartments with high ceilings. This floor installation technology “steals” the height of the premises quite significantly. So, the installation of the logs occurs according to the following scheme:

• or the concrete base is recommended to be leveled. Otherwise, the elements will not be in the same horizontal plane. Accordingly, they will need to be leveled by placing plates. This can lead to the floors in the apartment creaking.
• You need to lay a layer on the base, or treat the concrete with a special mastic. In the first case, the use of soft materials should be avoided. Over time, they will sag, and the floor will no longer be reliable and solid. For a waterproofing layer, roofing felt or polyethylene film is perfect.
• The logs are treated with an antiseptic compound and cut according to the size of the room.
• The installation process begins with installing joists at two opposite walls. These elements are leveled using a building level and immediately fixed to the concrete floor. Then a string is stretched between the installed joists. It will serve as a guide for the installation of other elements.

• The remaining logs are laid. The distance between elements directly depends on the thickness of the future.
• Insulation is poured between the joists. For this, ecowool or rolled materials can be used. In the second case, you need to mount the material as tightly as possible without leaving gaps between the layers.
• A layer of vapor barrier is laid down. This is a necessary condition for protecting the insulation from external influences. The vapor barrier can be attached using a stapler; the joints must be taped.
• You can lay a layer of plywood. This will serve as the basis for installing the flooring.

In order for floors to last a long time, you must strictly observe the spacing between laid parts. To do this, you can use the table.

Anchors

This method is used not only for fastening elements, but also to give the structure additional strength. It is quite problematic to pull out an anchor from a concrete base, so difficulties may arise when dismantling such a structure. Anchors are installed, like self-tapping screws, by drilling through holes. A locking element is inserted into the concrete, into which the bolt itself is screwed through the joist. In order for the bolt head to “sink” into the wood, the holes must first be countersinked.

Metal corner

Another way to install wooden elements on a concrete base. To do this you will need a galvanized metal corner. The installation process looks like this: the corner is attached to the joist using a self-tapping screw (the fastener must extend into the wood at least 3 cm). Then the corner is attached to the concrete surface with a self-tapping screw through a dowel.

One of the most important elements The floor structure is a log system. It is from strength, choice the right step Between the types of wood and the installation method, the operating conditions of the finishing coating will depend.

Choosing timber for logs

Timbers can have different sections and humidity levels

As already mentioned, it is the floor joists that perform one of the most important functions. Therefore, so that the floor coverings serve properly long term, you need to choose the right one construction material. It will be necessary to pay attention to many factors, otherwise the bars may deform under load and cause damage to the finish coating.

• Humidity. When choosing any wood building material, the first thing you should pay attention to is its moisture content. If the beams are not dry, they will not undergo strong linear changes during the drying process. Therefore, at the time of purchase, the timber should have a moisture content of no more than 16–18%. This humidity indicator is optimal, because the risks that the wood will gain moisture or dry out are minimal. It is worth noting that both of these processes can cause deformations, only their directions will be different.
• Type of wood. The joist system is designed to serve as a strong support for the finishing coating, so it must be strong. Choosing the highest grade is not necessary, because grade 2 or 3 wood will do just fine. The strength of the logs will be compensated by a large number of support points, so the main thing is that the lumber does not have areas with mold and fungi. When using a leveling system, you should pay attention to the number and size of knots. They can become areas where the support breaks.
• Section. The shape of the section can be determined by the end side. It is necessary to choose the material that will have a clear rectangular shape. Optimal ratio sides - 1:2 or 2:3, i.e. beams with a section of 50x100 mm and 100x150 mm, for example. In this case, the logs should be laid on edge. This position of the beam will be maximally resistant to vertical loads. The choice of beam cross-section should be based on the step at which they will be laid and what layer of insulation is planned to be used.
• Breed. The most common option is conifers, which have affordable prices and are perfect for supporting a finished floor. For example, pine or spruce are perfect for normal conditions, but where high humidity is expected, it is recommended to use larch. It is more resistant to moisture and can provide a good service life.
• Treatment. You need to ask sellers whether their lumber has antiseptic treatment. If there is no such thing, which often happens, then you will have to do it yourself. In addition to the antiseptic, which will protect against mold and mildew, fire retardants are used to increase the fire-resistant properties of the material.

Advice! You need to select lumber very carefully. It is best to select the samples you like from the warehouse yourself. This way you can get rid of the possibility that they will give you warped ones, which will be difficult to level, and you will have to do a lot of planing with a plane.

Choosing the right building material is only half the battle. It is worth dwelling on how logs are attached to wooden beams in a wooden house, to concrete floors and to the strapping system.

Joists on supports in a wooden house

For logs, bars with a cross section of 50x100 mm are usually used. From this it is clear that they are not the only strengthening system. That's why beams are used wooden houses on the floors, and on the ground floor and support pillars.

Supporting wooden support beams on poles

Installation of support pillars

The support pillars are made of brick with a wooden overlay, which should not allow moisture coming from the pillar to rot the wood of the beam.

The installation site for the pillars is dug to a depth of 50–60 cm, and a sand cushion is made. A layer of waterproofing from roofing felt sheets is applied, and formwork is performed with a height above the ground level of 30–40 cm.

After the concrete has been poured and dried, bricks are laid on it one level at a time, which will also have a concrete structure inside. To do this, during the process of pouring the concrete base, reinforcing wire is left under the pillars to the height that will be necessary for the height of one pillar. Excess sections of reinforcement are subsequently trimmed with a grinder.

Adjustable support for wooden floor beams

The step between the pillars for one beam is within the range of 60–100 cm, and between adjacent beams – 150–200 cm.

Attention! Plank flooring is usually oriented in the direction of the sunlight falling through the window. Therefore, it will be necessary to take this fact into account and orient the beams in the same direction as the finishing floor.

Beams

A layer of roofing felt is laid on the prepared pillars. In addition, during the manufacturing process of the pillars, it is installed on them wooden slats as an overlay.

The beams will rest mainly on strip foundation, and the pillars should serve only as reinforcing elements and in no case take the main burden. Therefore, their level should not exceed the level of the foundation tape.

Attaching to wooden beams

Attach the joists to wooden beams it will be as easy as shelling pears. It is recommended to use angles as fasteners. It is not necessary to attach the logs on both sides. To save on fasteners for large squares, you can attach the corners in a checkerboard pattern.

Joists on beams

When using mounts on beams, it is better to refrain from rigidly fastening the support slats to the wall. It is worth using an angle fastening with the possibility of shrinkage of the supports and movement of the screw. In this case, it is necessary to leave a technological gap between the wall and the logs.

Attaching joists to a concrete base

Screw for fastening joists and slats

The use of beams and pillars on a concrete surface is eliminated, because the logs will be laid and attached directly to the concrete surface. You can cope with this task alone. The order of actions will be as follows:

• A layer of waterproofing must be laid on the concrete base. As a moisture-insulating material, you can use roofing felt or ordinary plastic film. In this case, the joints must be airtight, so they are sealed with tape.
• The choice of lag laying step will directly depend on what finishing material will be used. For example, for floorboards with a cross-section of 35–40 mm, you can use a step of 60–70 cm.
• Using one log along the entire length of the room is not always possible. Therefore, it is necessary to make an even joint between the two parts so that the horizontal level at the junction coincides with the general level. To do this, they can use iron corners or special cuts in the tongue and groove. If this is done across the entire width of the room, then it is better to connect the joists in a checkerboard pattern so that subsequent loads do not cause fracture and deformation in this area.
• The first step is to secure the outermost joists. They will serve as beacons for leveling the remaining bars. To align two bars at large distances from each other, you must use a laser level.
• The logs are attached to the concrete base depending on their height. Thin bars are fixed through and through with dowels and spacers, which are placed in pre-prepared holes. And high supports - with special corners.

As a finishing coating on top of the bars, you can use sheets of plywood, which will serve as a subfloor under laminate or parquet.

Attaching the joist to the timber frame

When making a log system, they usually use a frame made of timber, which performs a strengthening function and allows the logs to be installed at the same level. In order to secure the logs to the frame, a simple method is used - the corners and brackets are installed on self-tapping screws. At the same time, the latter are advised to be installed slightly at an angle so that the logs cannot become loose during operation.

How to attach joists to a frame without using nails

The use of a strapping system is typical for frame houses and other types that do not have a rigid base, where an accurate and even connection is possible. When connecting bars with fasteners to a concrete base, squeaks may subsequently occur, but fastening only to the strapping will not cause this.

There are many in various ways fastenings that need to be used depending on the situation.

In the video you can see how best to attach wooden logs in a loggia in an adjustable manner:

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When building houses made of wood, builders often wonder about fixing the timber to the concrete floor, because these are two different materials, which means the fastening technique will be different. Wooden beams are secured using two methods: overhead installation and rigid fixation. Attaching the joists to the concrete floor will not only increase the thermal insulation of the premises, but will also hide possible unevenness of the concrete surface.

Appointments

Before installation decorative covering on the floors of buildings and structures, use the fastening of beams to the surface of concrete mortar. Using logs, a high-quality frame is obtained, suitable for further laying of coverings. In addition to the fact that the bars are an intermediate structural element, they also have the following purposes:

• provide the room with additional air flow;
• create sound absorption in the room;
• increase thermal insulation, thereby reducing heating costs;
• allow you to hide utility lines;
• create uniform loads on the foundation;
• provide the surface with an even structure, which is necessary for the finishing coating.

To attach logs to a concrete surface, you first need to maintain a certain gap between them. Use a board with a thickness from which the step size will be based when laying the beams on concrete. So, a board, two centimeters thick, is fixed to the beams in increments of 200 mm.

How to choose the right material?

In order not to make a mistake with the choice of material, take into account the following points:

• price;
• cross section in joists;
• variety;
• the wood from which the logs are made;
• length.

If your budget is limited, you don't have to buy expensive wood. Fir and spruce have no less service life if the material is processed correctly. It is not necessary to choose a flat surface and a solid color; these indicators do not matter. However, it is important to pay attention to humidity, which should not exceed 20%. Before use, the material is kept at home for a year, this will allow the lag to accept the humidity of the room and dry out.

Tools

To attach joists to a concrete surface, you need to use both wood and concrete tools. The following tools are used:

• jigsaw;
• perforator;
• chisel;
• anchors, screws.

To install an anchor frame for floors with joists, the following tools are used:

• hacksaw;
• building level;
• hammer drill

You can secure the adjustable frame in a concrete field using the following tools:

• chisel;
• finisher;
• laser level;
• drill and bit;
• hammer.

To fix the concrete floor to the joists, fasteners are chosen based on the budget. Self-tapping screws are cheaper than anchors, but the latter are more reliable. Anchor fasteners allow you to attach a wooden beam to the floor surface, pressing it, this is important when constructing a massive concrete surface.

Mounting methods

To attach the logs to the concrete floor, two types of timber laying are used. One of them is the lack of fastening of the joists to the floor. This method provides structural rigidity by fastening the lags to each other using a board. The disadvantage of this method is the possibility of shifting the floor covering. To avoid such a problem, fasten the log to the surface with anchors, corners or self-tapping screws.

Another fastening method is to attach joists to the concrete surface. Installation includes application thermal insulation materials and floor surface leveling solutions. This option for installing logs will save on expensive materials for insulation.

Self-tapping screws

Fastening the beams into the concrete surface using self-tapping screws significantly reduces the cost of the structure and simplifies the installation work. To do this, holes are made through the board using a drill, and points at the base of the floor are marked through them. This is necessary to make recesses in the coating and screw in the screws. The installation step should be within 4-8 centimeters. The distance between the holes is affected by the structure being manufactured. Self-tapping screws are used in a length depending on the thickness of the timber, but it should not be less than 0.5 cm. Experienced builders It is advised to choose self-tapping screws that have a so-called neck, this means that there is no thread in front of the head, which makes it possible to better attract the board to the floor surface.

Anchors

By using anchors in construction, greater resistance to tearing out is ensured. Which justifies the high price of the material. Their use is relevant in the construction of heavy structures with a large load on fasteners. Installation of anchor fasteners on a concrete surface is carried out according to the following instructions:

• Holes are made in the board and marks are made on the concrete through them. I make the same holes in the joists so that later I can hide the bolt heads in them.
• Using anchors, it is ensured reliable fastening beams
• Next, the locking elements of the anchor are placed into the resulting holes in the base of the floor, after which a bolt is screwed into them.
• The length of the fastener is different and can vary from 45 mm to 200 mm. The length and diameter of the anchor fasteners are affected by the thickness of the beams.

Corners

Fixing wooden blocks using corners occurs as follows:

• One of the sides of the corner is attached to wooden base screws. The insertion depth should be at least 0.3 cm.
• When fastening, you need to rest the free side of the corner on the floor. It must be fixed using the same method as fastening anchors and self-tapping screws, i.e., make through marks and insert dowels into them and screw in self-tapping screws.

Installation floor base using adjustable logs is relevant today due to its significant number of advantages. These include:

• elimination of surface irregularities;
• defects in the base of the floor in the form of cracks are hidden;
• Sound insulation and thermal insulation are provided;
• protection against fungus and rot is obtained.

Highly reliable fastening is obtained due to the presence of plastic bolts, which are a fastening and adjustable element. This design allows you to make a wooden floor on a concrete base of decent quality in a short time.

A significant advantage of this mount is the possibility of adjustable lags. This happens due to the ventilation features of the fastening. Applying adjustable joists, it becomes possible to hide utility lines. And possible thermal insulation will reduce heating costs.