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Floors on adjustable joists. Do-it-yourself adjustable floors using logs and plywood

Floors on adjustable joists. Do-it-yourself adjustable floors using logs and plywood

Currently, the main criteria that apply to sexual bases are strength and reliability, since it is on them that the quality of laying the floor finishing material depends. In order for the floor to be even, experts advise giving preference to adjustable structures that are built along the logs.

What you need to know about adjustable floors

hollow wear-resistant polymer bolts are used as adjusting elements;
the adjustable base is divided into two types: by plates and by logs;
if plywood is used as the base of the adjustable floor, then the bolts should be attached to the underside of the sheets;
when laying insulation between the concrete base and the adjustable floor, metal clamps should be fixed on the inner surface of the log;
logs should be located at a distance of 25-45 centimeters from each other, and the step under the tile should be small;
if there are no hollow polymer bolts, then the fastening mechanism can be made from a threaded anchor. In this case, wooden logs or plywood sheets are clamped on the anchor pin with washers and nuts;
adjustable floors with proper installation can last at least 35 years.

Adjustable floor device

An adjustable floor on logs is a floor device located on special boards, under which there is an underground space. Due to this, the floor surface does not need additional leveling with a concrete screed.

A threaded anchor for an adjustable floor is attached to the base, which can be wood, concrete or earth. The height of the floor is adjustable due to the possibility of the latch to rotate around its axis.

Anchors are attached to the base, depending on the type of subfloor:

fastening to a concrete slab occurs with the help of polypropylene needle dowels;
fastening to a wooden base occurs with the help of self-tapping screws;
fastening to a concrete screed occurs with the help of dowel-nails.

The anchor structure performs the following functions:

adjusts the height of the floor;
provides load separation;
enhances the strength of the connection between the subfloor and the adjustable one.

Benefits of adjustable floors

Adjustable floors have a large number of advantages, among which are:

the ability to use as a basis for any finishing material;
the possibility of carrying out installation on their own, since the work is quite simple and does not cause any particular difficulties;
ease of construction, due to which it can be used in the arrangement of loggias or balconies;
the possibility of laying communications or an insulating layer in the space between the flooring and the base;
installation of an adjustable floor on logs is a fairly dry and clean type of work, which allows you not to stain the walls during work;
wooden floors are able to cope well with differences exceeding 15 centimeters;
the cost of adjustable floors is more affordable compared to a concrete screed, which makes them more popular;
thanks to modern technologies, it becomes possible to equip a perfectly flat floor that does not create a creak.

DIY adjustable floors

Adjustable indoor floors

To begin with, you need to fix the logs on the base in increments of 30-50 centimeters, using screw-in rack bolts. Then the lags are leveled, for which the strut bolts are rotated along the axis using a special key. In conclusion, plywood is laid on the logs in a double layer, while the thickness of each sheet should be at least 12 millimeters. In the event that ceramic tiles are laid in the future, moisture-resistant plywood with a thickness of about 10-12 millimeters should be used to lay the top layer.

During the installation of the adjustable plywood, 16 through holes are made in the plywood using a spade drill. Then plastic bushings are inserted into them, into which bolt-racks are screwed. After that, you can begin to align the sheets by rotating the bolt-racks fixed to the base with dowels.

Attention ! To install the floor, it is necessary to use logs made of durable wood with a moisture content of 12 to 14%. They must be free from cracks or knots, mold or rodent infestation. The length of the lag is usually 2 meters, and the cross section is 4.5 by 4.5 centimeters. Before starting work, the material should be treated with special protective compounds. There must be enough air in the underground for ventilation.

The main advantage of such a floor is that it becomes possible to arrange a perfectly smooth and even subfloor on an unprepared base. Thanks to this, almost any floor covering can be used in the future.

Setting the horizon level with adjustable logs

By erecting a structure of this type, it is possible to mask any systems (ventilation, heating, electrical, etc.). If a “warm floor” system will be installed in the room, then its installation, made according to this design, will significantly reduce heat loss through the floor and, thereby, significantly save electricity.

Despite the fact that such an adjustable design is characterized by a fairly low weight, it is able to withstand heavy loads, which can reach up to 2500 kilograms per 1 square meter. Thanks to this, adjustable floors have found their application not only in the arrangement of living rooms, but also in warehouses, gyms and other premises.

Houses with such a floor construction can be erected even on soils in which heavy loads on the foundation are strictly prohibited. If the floor cannot be raised too high, then you can use a special design for adjustable plywood, in which the rise will reach only three centimeters.

The technology of its installation is almost no different from the installation of a log. The main difference is that instead of lags, naturally, plywood sheets are used.

Plywood is a material used not only in households, but also in aircraft construction, shipbuilding, furniture production and many other industries. With the help of plywood, you can easily replace a damaged area of the floor, because it goes well with floor coverings made of linoleum, laminate, carpet and parquet. But in order to avoid any misunderstandings, you need to know how to properly lay plywood.

Advantages of plywood over other materials:

the strength of the material is the same in all its directions;
sheets are large enough;
the formation of through cracks is completely excluded;
plywood bends easily;
transportation of material does not cause any difficulties;
has a low weight, but high strength;
plywood is characterized by high quality sanding and hard surface;
The material is waterproof and odorless.

Adjustable plywood is great in cases where the floor has distortions exceeding the mark of 15 centimeters, or communications pass through it.

Attention ! When adjusting the floor along the joists, the height of the room usually becomes lower by about 7-8 centimeters, so it is recommended to use it in rooms with high ceilings. In turn, when laying floors on adjustable plywood, the floor rises by no more than 3 centimeters, so the second method is considered more effective.

when choosing materials for leveling floors, you need to look for timber and plywood of the highest quality, since this show significantly affects the result of the whole work as a whole;
for ease of installation, it is recommended to purchase a laser level, which will allow you to achieve more accurate results;
floor slabs and the base must be as strong as possible, not crumble or crumble;
do not forget about the need for ventilation of coatings;
so that the floors do not creak, during the installation process, all surfaces should be cleaned of dust (as soon as the holes are drilled and the bolts are screwed, the surfaces are carefully vacuumed). In addition, the dowel-nails should be nailed as hard as possible so that the racks do not loosen;

When using this method, the logs are replaced with bushings, inside of which there is a thread (for this, special holes are drilled in the plywood). 6 plastic bolts are screwed into the bushings, which later need to be attached to the base with a dowel. A wrench should be used to level the adjustable plywood.

First you need to carefully level the first layer of plywood, then install the next layer and screw it with self-tapping screws. Before laying the second layer, it is necessary to carefully overlap the joints of the previous one, which will avoid the formation of seams. Thanks to the actions taken, the floor surface will become even and smooth.

Adjustable floor - subfloor in the form of a log or plywood flooring

As a rule, flooring in residential premises is laid on a concrete screed and logs. A relatively new option is subfloor construction in the form of a log or plywood flooring, the height of which can be adjusted with the help of special blocks-racks. This decision is quite understandably called - adjustable floor.

Adjustable floor technology involves the use of wooden logs or slabs (sheets of moisture-resistant plywood 18 mm), which are supported by stand-up bolts screwed into them, usually made of high-strength plastic. Turning the bolts around the axis changes the height of the lag or sheets, which allows you to accurately level the subfloor. After leveling the structure, the bolt is rigidly fixed to the base with a dowel-nail. In this case, the base can be either concrete (monolithic, hollow, with a screed), or wooden (beam). Sheets of moisture-resistant plywood are usually laid on top of the logs and any type of floor covering is already fixed on them - solid board, parquet, parquet board, laminate, linoleum, carpet, etc. In order to save money, massive boards are sometimes mounted directly on logs.

Benefits of an adjustable floor system

Such adjustable structures have a number of advantages. First of all, they have advantages over concrete leveling.

They are cheaper than concrete screed when leveling a surface with a height difference of more than 3-5 cm.
No need to fiddle with cement.
Installation of adjustable floors produced much faster pouring concrete screed.

In addition, they allow you to save money and time when arranging a base for plank flooring (parquet, parquet board, laminate), because concrete preparation in this case will include not only a screed, but also a self-leveling mixture.

Do not forget also about the need to create waterproofing (and often soundproofing) on top of the screed and a layer of plywood on which a wooden coating will be laid. In aggregate, the costs of such preparation will be higher than the costs of installing an adjustable structure.

Another important point: the installation of adjustable poles usually takes less than a week, since one worker mounts an average of 20-25 m² of adjustable logs or slabs per day. A completely different situation is with the base of a concrete screed: for parquet work, its strength must be at least 150 kg / cm², and the screed acquires such strength within 28 days. However, even this time period is not enough to start laying parquet or boards.

Note that European standards require drying of the screed up to 3-4%. It is a mistake to assume that it dries to this level in 28 days: this process takes longer than the curing process, and usually takes several months.

In the design of adjustable supports, there is no direct contact of wooden elements with the floor base, and, therefore, it is possible to lay logs over the concrete floor, and then plywood and parquet, without waiting for the concrete to dry completely. In the case of an overlap with high humidity, a plastic film is laid on it, which cuts off water vapor, after which the installation of logs or slabs immediately begins.

Finally, the adjustable floor design offers the possibility air movement under the floor and thereby removing excess water vapor that can lead to warping and rotting of wood. The inflow and exhaust of air is carried out due to the gaps between the floor and the wall of the room (there is also a gap between the plinth fixed to the wall and the floor). The standard value of this gap is 10 mm. If you need to improve the ventilation of the space under the subfloor, then you can install decorative grilles in the floor in opposite corners of the room for additional air inflow and exhaust.

Another advantage of adjustable structures is that they improve the sound insulation of the room: the floor is not monolithic, but contains an air layer in its “pie”. If it is necessary to increase the level of sound or heat insulation of the floor (for example, in a home theater or basement), mineral wool slabs can be laid between the joists. In addition, plastic racks dampen noise.

Adjustable floor slabs are laid on metal plates fixed on logs. The thickness of the insulating layer can be varied, while there is usually no contact between the slabs and the concrete base (they are separated by an air gap), so that in case of high humidity of the ceiling, the insulation will remain dry.

Next moment: height-adjustable floors allow laying engineering communications under the floor covering(pipes up to 100 mm in diameter) and any wiring. Moreover, communications will take the shortest path, so there will be fewer connecting nodes, therefore, the reliability of the system will increase, and the cost of its installation, on the contrary, will decrease.

Adjustable floors on logs or plywood boards have obvious advantages over concrete leveling, if we are not talking about an abstract "concrete screed", but about a base for parquet, parquet board or laminate, which includes layer, layer and layer. Adjustable structures are cheaper than such a base, especially when it is necessary to level the floor with strong differences in height.

In addition, it gains strength within 28 days, while the installation of an adjustable floor usually takes from 2-3 days to a week. In addition, engineering communications and wiring can be laid under the adjustable floor, and, if necessary, heat and sound insulation slabs. However, in itself, such a floor increases the sound insulation of the room due to the air cushion between the floor covering and the ceiling, as well as through the use of plastic bolts-racks.

Problems and disadvantages of adjustable floors

One of the problems that arise when using a wooden floor is creak. Is it likely to appear in floors on adjustable joists or slabs? Experts say that with a quality installation of the system, there will be no creaking. It can occur when the floor elements do not fit tightly to each other, for example, when the bolts are incorrectly attached to the base or the gaps between the end joints of the log and plywood are formed incorrectly. However, with a qualified installation, all elements of the system are so rigidly fixed on the base and interconnected that even a slight drying of the wood, according to experts, will not result in floor creaking.

However, possible knocking on the floor if the concrete base on which the logs rest is made with errors: for example, if the screed applied to the ceiling crumbles or cracks. Then it is recommended to remove a bad screed before installing the floor, as well as to correctly select the dowel-nail model for attaching the bolt to the base.

Poor cleaning of dust during the installation of adjustable structures leads to dust particles entering the gaps, which can lead to creaking in the floor.

We add that the maximum allowable pressure on adjustable structures can reach 3 tons per 1 m², which corresponds to a large margin of safety of the floor. Their estimated service life is at least 50 years.

Another of the possible (not everyone even notices it) disadvantages of adjustable floors can be called a kind of rumble when moving on them especially if the shoes are high heels or the soles are very hard. This is especially pronounced if you jump on such a floor.

Installation of adjustable floors

If it is necessary to raise the floor by 50 mm or more, install adjustable log design. And if the required lifting height is from 30 to 50 mm, apply system of adjustable plates (plywood).

Adjustable log system (adjustable floor on logs).

When installing the floor on a concrete floor, logs with a section of 45 x 45 mm and a length of 2 or 3 m are most often used. Their standard step is 300 mm between the axes of the bars. When laying the floor on a floor of wooden beams, logs of a larger section are usually required, its value is selected taking into account the step of the beams (as a rule, logs with a section of 45 x 70 mm are used). You can also vary the step lag. For each log there are 5 bolt-racks with a diameter of 28 mm, under which threaded holes are prepared at the factory.

The length of the bolts is usually 100 or 150 mm: it is chosen depending on how high the floor needs to be raised. The installation of the structure begins with the fact that bolts are screwed into the logs, then the logs are laid out on the base with the required step and holes for the dowel-nails are marked. Moreover, a gap of about 10 mm is left between the lags and the walls.

First, bolts are screwed into the logs, after which they are laid out on the base, outlining and then drilling holes for dowel-nails

Log alignment is carried out using a level and a hex key

After that, they begin to level the lag by rotating the bolts with a hex key (the bolts have a hex groove), using a level.

Adjustment of the height of the plastic bolts is carried out using a special hex key

Having completed the alignment, the dowels are hammered all the way into the base, and the protruding part of the plastic bolt is cut flush with a chisel.

After leveling the lag, the dowels are driven all the way into the base

Then plywood flooring is mounted. According to the recommendations of the system manufacturers, the thickness of the deck should be at least 18 mm. However, many experts recommend making flooring up to 30 mm thick with a lag step of 300 mm for parquet and solid board.

As a rule, two layers of plywood sheets are laid (overlapping the joint of the two lower ones with the top sheet) to ensure maximum structural rigidity. As a rule, plywood layers are fastened with self-tapping screws, but experts are increasingly recommending that in addition to this, it is imperative to glue the top layer to the bottom. A floor covering is mounted on top of the plywood.

We add that there are other adjustable designs on the market. In particular, systems where metal rack bolts (anchors) are used, and adjustment takes place using a nut with a support washer screwed onto them.

There are also systems with U-shaped metal brackets that “wrap around” the log from the sides and fix it with self-tapping screws. The bracket has a number of holes, and after alignment, the screws are screwed into holes that are suitable in height.

Reliability of the floor structure according to adjustable joists is achieved due to the correct choice of the section and lag pitch in combination with the thickness of the subfloor, as well as due to high-quality installation. In a standard situation, the lag step with a section of 45 x 45 mm should be 300 mm with a subfloor thickness of 30 mm (usually these are two layers of plywood with a sheet thickness of 18 and 12 mm). Plywood layers should be glued together to achieve maximum structural rigidity.

There is an exception: in the case of using a parquet board fixed to the base with glue, it is enough to lay one layer of 18 mm plywood, since such a board and plywood have the same thermal expansion, and the rigidity of the structure is beyond doubt. The cross section and step of the lag change, as a rule, when the floor is laid on top of the floor of wooden beams. The distance between the beams can be quite large (1 m or more), so you either have to increase the cross section of the log, or set the logs with a smaller step and increase the thickness of the two-layer flooring - from plywood or a combination of grooved board and plywood.

The price of components for adjustable floor structures is from 400 rubles/m². Adjustable plywood floor mounting kit

Adjustable plate system (adjustable plywood floor).

The technology for mounting an adjustable plywood floor is somewhat different. A hole is drilled in plywood, into which a plastic sleeve with a diameter of 60 mm is inserted, having a threaded hole. The sleeve is fixed on a log or plywood with self-tapping screws. Then a bolt-rack is screwed into the sleeve, after which the entire cycle of the above works is performed.

Technology of the system of adjustable plates (plywood):

	1. Drilling holes in plywood and fixing plastic bushings with self-tapping screws;
	2. Screwing the stud bolts into the bushings
	3. Fastening bolts-racks with metal dowel-nails to the base

Those who want to level the floor for laying the coating were not too spoiled by the abundance of screed options. Those who wanted to save on materials had to work hard with lining wood chips or adding sand under the logs, or waiting a whole month for the cement to harden. For those who weren't looking to cut costs, they had to shell out a hefty sum for polymer leveling compound. Adjustable floors have become an alternative to outdated and expensive technologies. Their construction allows you to save money and reduce the duration of repairs, and even do the work yourself.

Is it worth doing adjustable floors at all?

The list of advantages of leveling systems with adjustment includes all the priorities inherent in light dry screeds, arranged on logs or on point supports with flooring made of chipboard or OSB panels, plywood, GVL boards. Excellent ventilation, minimal weight, the ability to lay engineering networks, etc. The principle of their operation and construction is similar, the only difference is the use of special screw devices. It is they who facilitate and accelerate the laborious process of placing structural elements horizontally, which takes a lot of effort and time from the performers.

The adjusting devices consist of plastic support bolts with an external thread and an internal cone-shaped cavity and dowel-nails. Plastic bolts are inserted into the holes drilled in the logs or in the plates. After laying the dry screed elements together with the bolts in their place, the leveling structure is fixed to the base floor. To do this, a dowel-nail is inserted into the internal cavity of the bolt and hammered with a dowel.

Dowel-nail fastening is carried out if the leveling structure is installed on a concrete base. Fastened to wooden floors with galvanized self-tapping screws.

Control devices simultaneously perform three functions:

serve as reliable supports for the lag system or for plywood sheets;
work as guides for installing fasteners connecting the subfloor to the base base;
and most importantly, they help in the shortest possible time to adjust the position of the rough flooring in the horizontal plane by simply turning the screws.

The construction technology is so simple that adjustable floors with their own hands can be built by a home master who has nothing to do with construction specialties. You can even make your own adjustable dry screed according to the type of factory systems. Difficulties may arise with the purchase of a support bolt made of heavy-duty ABS polymer. However, a number of manufacturers offer leveling structures only with a metal stud bolt, along the external thread of which logs or plates move down / up.

The simplified design of adjustable floor bolts consists of metal rods with external threads. At the bottom, they are equipped with elements for fastening to the base floor, at the top with a device for adjusting and fixing the log or plywood in the required position. There is another option with metal U-shaped parts attached to the floor and to the logs with screws, but there is much more fuss with them and the adjustment is performed according to a slightly different scheme.

Two technologies for the construction of adjustable floors

As mentioned above, either logs or plates are equipped with support bolts. The choice of leveling system with adjustable joists or slabs determines the planned height of the subfloor:

If it is possible or necessary to raise the floor to a height of more than 5 cm, the owner should pay attention to structures with lags;
If it is undesirable to greatly reduce the space, and it is planned to raise the surface by a distance of 3-5 cm, a leveling system with adjustable plates will do.

In both cases, similar adjustable feet are used to create a level floor surface. Only the support-bolts and anchors for the lags are longer, since they have to “pass through” and also hold the beam on themselves. There is a difference in the arrangement of holes for screw devices and in the methods of installing a dry screed.

General rules for preparation

To select the type of adjustable structure, we determine the height at which the rough flooring will have to be fixed. We focus on the level of the floor in the room with the previously laid coating, the thickness of which will need to be subtracted in the calculations. We take into account the height and location of underground communications, if any, and the height of the lower plane of the doors. In accordance with the difference between the actual and planned level of the floor surface, we choose the option of an adjustable system.

Then you will need to measure the equipped room and draw a plan. Having a simple drawing in hand, it is easier to calculate the amount of material and hardware for fastening, it is easier to determine the optimal layout of whole and cut elements.

Regardless of the type of leveling structure around the perimeter of the room, it is necessary to leave a ventilation gap of at least 1 cm. A similar gap should be between adjacent slabs and between inserts used to equip areas not covered with whole sheets.

In the drawing, we “lay out” the plates with specified dimensions that are available in the factory or in free sale. After all, they will be covered in both cases. We determine the step of drilling holes, depending on the coating chosen for the final laying. To form an ideal dry screed for floor tiles or linoleum, there should be no more than 30 cm between the axes of the holes. The maximum distance between the centers of screw devices is 50 cm when leveling with plates. When aligned with 45 cm lags.

If it is planned to install a structure with adjustable joists, followed by laying plank floorboards, it is not necessary to nail plywood to the leveled joists. It will be possible to fasten the board immediately to the timber, which should not be forgotten when determining the level of the subfloor.

Floor construction with adjustable joists

There are mandatory rules for marking drilling points in a beam for plastic bushings-supports:

to drill the first hole from the end of the log, it is necessary to retreat 10 cm;
the distance remaining minus 10 cm from both ends must be divided into equal segments;
between the walls, ends and the side plane of the first log there should be a distance of 1 cm for ventilation;
logs are set at an equal distance according to the selected step;
ordinary logs are positioned so that the edge of each of the plywood sheets rests on the timber. Do not forget that between the plates you need to leave a centimeter gap.

Installation and fastening of the lag structure is carried out in accordance with the algorithm proposed by the developers of dry leveling systems:

At the points marked on the beam, holes for the support bushings are formed with a pen drill, which then need to be inserted there and screwed with screws. Flush with the plane of the beam, we only recess the extreme bolts, with the help of which the adjustment will be carried out.
We put the log with the bushings in the planned place and through the internal cavities of the bushings we outline points for the dowel-nails on the base base.
We remove the log, drill holes in the concrete with a puncher 4-5 cm deep at these points.
We return the log to its rightful place, we put fasteners into the bushing bolts.
We hammer only the extreme dowel-nails with a dowel. We do not beat "to the stop", we will perform the final driving after leveling. Ordinary dowel-nails are not fixed at all until the lag is accurately aligned and adjusted horizontally.
Using a hexagon, we adjust the position by rotating the two extreme bolts. We control the actions with a level gauge.
Found the perfect position? We finally fix the extreme dowel-nails. We screw the ordinary plastic supports all the way into the base floor and hammer in all the fastening elements inserted into the support bolts with a hammer.
All the excess protruding above the surface of the lag is carefully cut down with a chisel flush with the upper plane of the beam.

Similarly, we install each element of the floors constructed along adjustable lags. Then we nail or screw plywood to the beam with screws in one layer, if the sheet thickness is 18 mm or more, in two layers, if we have sheets with a thickness of less than 12 mm. The maximum spacing of the boards is 15 cm. The butt joints of the second layer of plywood must not coincide with the butt joints of the first layer.

Every time after drilling holes in concrete and wood, the floor and adjustment devices must be dedusted, otherwise the finished floor will creak.

Adjustable plywood rules

Masters leveling the floor using adjustable plates should adhere to the following recommendations:

The optimal distance from the edge of the sheet to the center of the extreme support-sleeve is 6 cm, the specified limit cannot be exceeded.
After marking the position of the extreme bushings, the plate must be divided into equal, preferably square segments. The maximum side length of the square is 50 cm.
Inserts should be equipped with at least 2 rows of screw supports, regardless of the calculated pitch.

To reduce and facilitate the marking of the plate, we lay it in a pack. We drill the first sheet of plywood lined from above with a pen drill through so that a trace remains on the plate lying under it. At these points, we form holes in the second plate, etc.

Further actions are carried out by analogy with the technological scheme described above. The only difference is that you will have to adjust with the help of a hexagon not the extreme two, but four bolts.

Since it is not too easy to mark the attachment points on the base floor through a rather voluminous sheet of plywood, we stand on it with our feet. So we will fix the plywood and will not let it move.

After driving the dowel-nails with a doboynik, the strength of the installation of fasteners must be checked. Elements that do not inspire confidence must be dismantled and replaced. Before finishing laying the flooring, the surface must be dedusted without fail. There will be no specks and dust particles, the adjustable floor will never creak.

If you follow the rules for installing a dry screed, the alignment will be perfect and the rough base will last half a century. Overlappings will be better preserved, moisture from which will be regularly removed by natural ventilation. And the owner will not lighten his own wallet for a very weighty amount saved on the services of builders.

The technology, new for many of our compatriots, makes it possible to significantly reduce the time for arranging floor coverings. Like any technology, in addition to its advantages, it also has rather “problematic” characteristics. But this is the professionalism of builders, in order to be able to choose among the numerous options for flooring the one that will be optimal in this particular case.

Finishing floor coverings are installed on wooden logs (in the case of floorboards) or on a solid base of plywood or OSB sheets (in the case of laminate or soft flooring).

A very important point during the construction of any floors is that the bearing surface must be in a strictly horizontal position.

It is very difficult to achieve such a result with the help of fixed logs; it is often necessary to use various wedges or linings to align the spatial position. These wedges may fall out due to improper fixation or due to other reasons, the floors begin to sag and creak. It is impossible to eliminate such problems without dismantling some of the coatings, and dismantling is associated with large losses of time and money.

Do-it-yourself adjustable floors - a diagram of one of the possible options

Adjustable floors allow you to perfectly level surfaces on any uneven ground. In addition, the leveling mechanism makes it possible to adjust the gap between the floor and the supporting base, and this allows you to place various engineering networks in these places.

Adjustable floors consist of plastic bolt-posts or metal studs, floor joists or plywood sheets. There are many modifications of control systems, but there are no fundamental differences between them. With the help of rotation of the threaded connection, a smooth lowering / raising of structural elements occurs, in this way it is possible to accurately set the base of the floors in the required position.

There are several types of adjustable floors, you should familiarize yourself with them in more detail.

Adjustable floor. Kinds

Table. Types and brief characteristics of adjustable floors

Types of adjustable floors	Characteristics	Illustration
With plastic adjustment mechanism	They can be sold complete with lags or separate sets. Installing factory floors is much faster, they have cut threads in the logs, there is no need to mark and drill holes. The dimensions of the log are 30 × 50 mm, the distance between the bolts is 40 centimeters. Logs are recommended to be installed in increments of 30 ÷ 40 centimeters, specific values \u200b\u200bshould be chosen taking into account the expected maximum load on the floor.
With metal adjustment mechanism	Instead of plastic joints, metal studs with nuts and washers are used. They can withstand increased loads, but working with them is somewhat more difficult.
On metal corners	Advantage - the stability of the lag increases, it is possible to create complex floor designs, taking into account the peculiarities of the layout of the rooms. The disadvantage is that the installation time is significantly increased.

Both logs and plates can be regulated. The second option is used only for soft flooring or laminate flooring, the first option can be used for all types of floor finishes.

If desired, you can make adjustable floors yourself, this option has its undeniable advantages. The main ones are significantly lower cost and the ability to select lag parameters depending on the specific features of operation. If desired, the system of adjustable floors allows for floor insulation, which is very important in conditions of high energy prices.

Installation technology of factory adjustable logs on plastic bolts

Initial data. Bearing base - concrete or cement-sand screed, a set of factory-made adjustable logs is used. Let's say right away that this is the most expensive option for adjustable floors.

Step 1. Take measurements of the room to determine the amount of lag. The floors in the bath do not have a large load, the distance between the lags can be increased to 45 centimeters.

Step 2. Beat off the distance between the lags on the screed. To do this, use a rope with blue, with its help the work will be done quickly and efficiently.

Step 3 Cut the lags to the required length. The length of the sold factory logs in most cases is four meters. Think carefully about how you need to lay out the lags to minimize waste. The distance from the cutting line to the nearest adjusting bolt must be at least ten centimeters. If the end is closer, then there are risks of cracking under loads.

Step 4 Spread the logs around the marked lines. For installation, you will need a small drill with a hammer drill, a special wrench for screwing in the bolts, a doboy to fix the dowels, a screwdriver, a chisel and a hammer.

Step 5 Set the first log in a vertical position, screw plastic bolts into the threaded hole. Place the lower ends of the bolts on a line and drill a hole in the concrete base for the dowel. The depth of the holes for the dowel should be 2÷3 centimeters greater than its length. This is due to the fact that a certain amount of concrete always remains in the hole, if you do not make a margin in length, it will prevent you from hammering the dowel completely.

Step 6 Start the dowels, but do not hammer them all the way. The dowel must not interfere with the rotation of the plastic bolts. Using a long level, set the correct position of the lag. If the lag is installed, firmly fix the dowel. Continue to install lags in turn in the marked places, constantly control their position with a level.

Such an installation algorithm is offered by manufacturers, this is what many builders do, who receive wages not from production, but by the hour. The one who works from working out does it differently. How? They take the hydro level and on two opposite walls beat off the zero level of the lag. Then they drive in carnations or dowels in these places (depending on the material used to make the walls) and pull the ropes. The ropes are stretched so that they are at the ends of the lag. If the length of the room is not more than the length of the lag, then two ropes will be needed. If the logs had to be connected, then three. The rope is pulled only after the lags are already placed at the fixation points.

Then everything is simple and fast. Each lag is installed along the rope, it should not touch it, you need to check that the gap between the rope and the lag is minimal. That's all, in this way you will be able not only to significantly increase the speed of installation of an adjustable floor, but also significantly improve its quality.

There is a direct relationship between accuracy and the number of measured planes. What is meant? It is highly likely that the position of the first lag deviated from the desired level by one millimeter. It's a little, everything is fine. But the fact is that the following checks will be done taking into account this deviation, again there is a possibility of an error in a millimeter, and so on increasing. It is for this purpose that a template is made if you need to cut off a large number of identical parts, and do not take dimensions from each finished part in turn. In this case, the rope acts as a template.

Step 7. Rebuild with a wide chisel, cut off the protruding part of the plastic bolt.

Floor on plastic bolts - check

Video - Adjustable floor installation technology

The main advantage of such floors is that the fastening stability is significantly increased due to the increase in the area of the lower stop. The disadvantage is that the terms increase, the inability to do the work on their own.

The lags are fixed to the U-shaped plates using self-tapping screws, the height adjustment of the lag is carried out using a series of vertically located holes on both sides of the plate.

Step 1. Using a blue rope, mark the locations of the genital lags. Calculate the required amount of material and additional structures.

Step 2. Determine the level of the floor, make marks on the walls. Arrange metal plates and logs along the lines. The width of the plates must match the lag tire. The distance between the plates depends on the parameters of the lag, forty centimeters are enough for a bath.

Step 3. Fix the plates to the concrete base with dowels. Hammer the dowels immediately to the stop, then it is very difficult to pull them up - the lag lies on top and prevents access to it. If during fixing the metal plates moved a little, it's okay. When installing the logs, slightly bend their side parts in the right direction.

Bracket fixation

Step 4 Take the first log, put its ends in the right position. In this position, attach the log to the side surfaces of the U-shaped plates, use wood screws to fix it. Now you can fix the plates located in the middle of the log. But for this, constantly check the horizontal position, the lag bends a little under its own weight. If you want to do the work faster and better, then use the ropes to set the horizontal level. How this is done is described above. Make sure that the screws do not split the logs, choose them according to size, screw them in at a slight downward slope.

Step 5 After installing all the logs, you need to cut off the protruding parts of the plates with a grinder. Doing this is quite inconvenient. But, despite the “difficult” cutting conditions, try to minimally damage the wooden logs with the disc.

Installing a lag on metal studs

Adjustable floors of this type can be made independently, we will talk about this option. Select the dimensions of the log, taking into account the characteristics of the floor and maximum loads. Zinc coated metal studs, recommended diameter 6÷8 mm. To assemble the structure, you will need studs, nuts and washers.

Step 1. Beat off parallel lines on the supporting base at a distance of 30 ÷ 50 cm. The greater the distance, the more powerful the lags you need to choose.

Step 2 Make a calculation by the number of logs, studs, washers and nuts. The recommended distance between the studs is 30 ÷ 40 centimeters. Prepare all materials, additional elements and tools for the production of work.

Step 3. Mark the holes in the lags for the studs, they should all lie on the line of symmetry. In the marked places, first drill a through hole Ø6 mm for the stud (if the diameter of the stud is different, then the hole must be drilled accordingly). On the front side of the log, drill a hole for the diameter of the washer with a pen drill. The depth of the hole should be several millimeters greater than the sum of the height of the nut and the thickness of the washer.

Step 4 Lay each lag in turn on the broken parallel lines on the concrete screed. Very carefully, in turn, for each lag, make marks for future installation sites for anchor threaded elements. Make sure that the lag does not move. For marks, use a drill or an ordinary pencil. For a drill, you need to take a drill with a victorious soldering. The places are marked - take away the log and drill holes in the concrete. The dimensions of the hole must match the dimensions of the anchors.

There is a second way to mark the holes for the anchor, it takes more time, but it completely eliminates the possibility of errors. It is done like this. First, you need to mark only the two extreme holes for the anchor, screw the studs into them on two nuts and fix the log in the desired position. Now, during further marking, the lag will not move anywhere. In this position, you can immediately drill holes for the anchor to the full depth. The work is done - the lag is removed, all the studs are screwed into place. Such a procedure will have to be performed with each lag, labor productivity decreases two times. But you yourself must make the final decision on the method of marking, taking into account the condition of the concrete base of the floor and your experience in performing this kind of work.

Step 5 Place a nut on each stud and a washer. It is advisable to immediately approximately determine the location of their location in height, this will speed up the work. Screw the studs into the anchors firmly. To do this, you can use a special locksmith fixture or other simple methods. You can buy studs that have holes at the end for a plug-in barb or a hexagon for an open-end wrench, but they cost much more than ordinary ones.

Video - How to twist hairpins

Step 6. Put the logs on the studs one by one, with a wrench of the appropriate size, by turning the lower nut to the left / right, align the position of the log. How this is done, we have already told. Keep in mind that metal nuts have a much smaller thread pitch than plastic nuts. In some cases, it will take a long time to turn, which is tiring. Moreover, the position will be uncomfortable: you will have to sit on your knees, and bring the key from below the lag.

Step 7 The lags are set - you can start fixing them. Use a washer and nut, insert them into the top hole.

Important! Tighten the top nut with great force, even a slight loosening can cause very unpleasant squeaks while walking on the floor.

Step 8 Cut off the protruding ends of the studs with a grinder. Be careful with lags, do not damage the integrity of the lumber with a saw blade.

Installing floors with leveling plywood

Such a subfloor is suitable only for laminate or soft floor coverings. For installation, you need to buy a set of factory-made elements, the work is more difficult to perform.

Step 1. Mark on the plywood sheet the installation locations of the bushings, drill holes of a given diameter. The bushings should be evenly distributed over the entire area of \u200b\u200bthe sheet, the distance between them is not more than thirty centimeters. Drill holes vertically, if the edges are at an angle, you will have to re-drill them. This takes time and significantly increases the installation time of the adjustable floor.

Photo - drilling a hole in plywood

Step 2. Insert the threaded bushings into the holes from the bottom side, fasten them with small self-tapping screws, they should not turn during the adjustment of the floor height. Manufacturers provide four places for fixing the bushings, so many are not needed, it is enough to fix it with two self-tapping screws.

Step 3. Make markings on the floor, try so that the sheets do not have to be “shredded” into small pieces. Markup is a plan for cutting sheets. It is advisable to draw it on paper, think over several options, and only then it will be possible to choose the best one from them.

Step 4 Screw in all the plastic bolts, turn the plywood sheet in the desired position. Screw in the bolts the same number of turns. After installing the first sheet of plywood, note at what level the bolts are located. In the next sheet of plywood, try to screw the bolts in the same position.

Step 5 Using a special wrench, screw in / unscrew the bolts until the plywood sheet is in a strictly horizontal position at the required height. Constantly check its position with a level in several planes. Very important! All bolts must have a slight tension, otherwise the plywood will sag. The work is quite difficult, do not make plywood sheets large. You must reach each bolt from the concrete floor. It is very difficult to adjust the position of the plywood sheet and at the same time be on it.

Keep in mind that the fasteners to the concrete base are not fixed, the floor turns out to be “floating”. This factor should be taken into account when deciding on the arrangement of floor coverings in each particular room.

Step 6 After installing the last plywood sheet, check the position of the subfloor again. Remember that the adjustment parameters do not exceed 2÷3 centimeters. If the concrete base has too large irregularities, then you will have to level it first. Plywood should only be waterproof.

Do not use chipboard, OSB, or other materials in place of heavy-duty plywood, although some manufacturers recommend such. Pressed materials react very poorly to point multidirectional forces, in these places they quickly lose their original bearing capacity. Namely, such loads are present in the places of adjustment of the plates. Let plywood cost much more, its price will pay off during the operation of the floor.

Name	The size	Variety	price, rub.
Plywood FC unsanded	4x1525x1525 mm	4/4	RUB 247.00/piece
Plywood FC unsanded	6x1525x1525 mm	4/4	RUB 318.00/piece
Plywood FC unsanded	8x1525x1525 mm	4/4	RUB 448.00/piece
Plywood FC unsanded	10x1525x1525 mm	4/4	RUB 560.00/piece
Plywood FC unsanded	15x1525x1525 mm	4/4	RUB 738.00/piece
Plywood FSF unsanded	9x1220x2440mm	3/3	RUB 1,048.00/piece
Plywood FSF unsanded	12x1220x2440mm	3/3	RUB 1,345.00/piece

Do not forget to leave gaps 1÷2 centimeters wide around the perimeter of the room near the walls for natural ventilation and compensation for the expansion of wooden structures. These gaps are then closed with skirting boards and become invisible.
For logs, choose only high-quality lumber with a minimum number of knots. Large cracks, visible fungal diseases and mold infestations are not allowed.
Do not drill holes for studs on knots, it is better to move them a few centimeters. The fact is that wood in the event of a violation of the integrity of a healthy knot significantly loses its strength. The device of adjustable floors assumes the presence of efforts not over the entire area of \u200b\u200bthe log, but only at several points. This feature requires increased strength indicators from wood. This remark also applies to the bearing base of the floor, point forces also act on it, the load per square millimeter increases significantly. Accordingly, concrete must be strong, it is not allowed to deviate from existing building standards during its manufacture. Any deviations in strength will lead to the fact that over time, under the stops, the base will be destroyed, the floors will begin to sag and, as a result, it is very unpleasant to creak. It is impossible to eliminate these sounds without dismantling the entire structure.
The higher the level of the adjustable floor above the ceiling, the more it "sounds". To reduce the noise level, it is recommended to use pressed mineral wool. At the same time, it will insulate the floor.

And the main advice in conclusion. Use adjustable floor options only as a last resort. Practice shows that the number of disadvantages of such structures exceeds the number of advantages. The cost of only adjustable logs can exceed the total cost of flooring made in the usual traditional way. Decide what to do faster: immediately put a few lags or drill dozens of holes in them and then “screw” them in the sweat of your brow with bolts and nuts.