We make an adjustable floor on joists instead of a concrete screed

Concrete screed, due to its structure, does not allow the formation of a surface that would be sufficiently smooth, and now, more and more often, mixtures such as “Betonite” or technology are used instead. A good alternative to all these “wet”, and therefore labor-intensive and dirty technologies, is the floor on adjustable joists Oh.

These structures have special adjustable supports for the logs in the form of plastic post bolts. Moreover, the adjustable logs can be raised or lowered along the threads of these post bolts and thus easily adjusted to the level, which guarantees perfect level base under finishing, which means no creaking floors.

Advantages of an adjustable floor on joists

Compared to leveling with concrete screed, adjustable joists offer the following advantages:

• wet and dirty technical processes are excluded;
• a wide range of floor lift levels from 5 to 15 cm and higher is provided without any additional material and labor costs;
• obtaining cost savings when raising the floor over 7 cm;
• speed of the installation process (100 m2 in two days);
• guarantee high precision alignment;
• increased heat and sound insulation;
• placement of all types of communications in the underground space, which makes it easier to access them during repair or replacement;
• the lightness of the design, making it indispensable in houses where a large load on the floors is technologically unacceptable.

The following design options for adjustable joists are possible.

Also read materials:

• Standard set of plastic post bolts and fastening elements for concrete + separately purchased wooden beam under the logs. This option involves the maximum amount of DIY work. It will be necessary to drill holes in the joists, and then cut threads into them with a tap for plastic post bolts.
• Standard set of plastic bushings, post bolts and fastening elements to concrete + separately purchased wooden beam for logs. Unlike the previous option, here after drilling the holes in the joists, ready-made plastic bushings with internal thread, which are attached to the joists with self-tapping screws.
• A standard set of adjustable joists, including wooden joists with ready-made threaded holes for post bolts, as well as a set of post bolts themselves and elements for fastening them to concrete. Plastic post-bolts have internal through cone-shaped holes for passing through them the fastening elements of the post-bolts to concrete (dowel-nails) or wood (screws). Moving down in such a hole, the dowel-nail self-centers along its axis. In the upper wide part of the hole, a hexagon wrench is formed for screwing the stand bolt either into a threaded bushing or directly into a threaded hole in the joist.

Installation of the floor on adjustable joists (video)

The main stages of installing an adjustable floor on joists

Preparatory work

1. The room in which it is planned to install adjustable joists is measured. Based on the measurements, the amount of timber for the logs with a margin for cutting, bolts-posts for installation and dowel-nails for attaching them to concrete are calculated.
2. The level of the floor slab is checked and the final floor level is set taking into account the height of the flooring (plywood, OSB) and the height finishing coating.
3. In the logs with the required pitch, through holes are drilled with a feather drill, then, if you do not have threaded bushings, threads are cut into the holes with a tap. If you purchased ready-made plastic bushings, they are inserted into smooth holes and fastened to the joists with self-tapping screws.
4. The stand-up bolts are screwed into the holes of the joists using a hex key - the outer screws in each joist are screwed in completely, and the middle ones - to a small depth.

Important! If the surface of the floor slab under the post bolt is very uneven, it should be leveled with a chisel. The post bolts must be securely fastened to the concrete. The minimum distance between the floor slab and the joists should be 10 mm.

Installation of logs

• First, logs are installed along the perimeter of the room with a distance of 10-70 mm from the walls, the distance between the wall and the ends of the logs is 10-30 mm. When choosing a pitch between lags, you should take into account the dimensions of the flooring sheets (slabs). The edges of the flooring slabs should rest on the joists and end near their central axes. The standard step size between the logs is 400-600 mm, however, to strengthen the structure, this step can be reduced to 300 mm. It is allowed to install cut-off joists supported by two stand-up bolts.
• The outermost bolts in each joist are installed first. They are screwed into the joist to the required depth, controlling the preliminary position of the joist by level, after which all other stand-up bolts are lowered to the level of the slab.
• After this, a thin drill is inserted into all the holes of the post-bolts and holes are marked in the concrete for the dowel-nails.
• The lag is removed and the planned holes are drilled in the concrete. The joist is reinstalled, a dowel-nail is inserted into each bolt-post, which is lowered down the cone-shaped hole and falls exactly into the hole drilled in the concrete.
• Next, lightly recess the dowel-nails in the 2 outer bolts-racks using a hammer. The log is set to the required height by rotating the two outer bolts with a hexagon, controlling the process by level.
• The outer dowel-nails are finally driven into the concrete. Then screw the remaining stud bolts into the joists until they rest on the slab, recess and hammer the dowel nails into each stud bolt.

Using a chisel and a hammer, cut off the protruding ends of the bolts from the upper plane of the log. Check the rigidity of the fastening of the post bolts to the floor slab by pressing on each joist and trying to tear it off (lateral loosening is prohibited).

If any post bolt is not sufficiently fastened to the floor slab, it is unscrewed. Remove the dowel-nail and increase the depth of the hole in the concrete. The holes are cleared of dust and the post bolt is reattached.

If the required rigidity of fastening to the base is not achieved, then use other fasteners. For example, in the form of RDK - a nylon expansion dowel with a screw. The screws in the RDK dowels are tightened using a long bit with a screwdriver or drill. The screw must not be loosened or turned in the dowel thread.

Installation of the floor on adjustable joists (video)

Adjustable logs on metal studs

Let's consider how you can arrange adjustable logs from materials that can be purchased at any building materials store.

Regular steel studs can be used as adjustable supports for joists. The design of such adjustable lags on heels is as follows.

• A standard dry planed timber with a cross section of 50x50 mm is used for the logs. Its adjustable support contains an M 6 pin, two nuts, two washers and an anchor sleeve.
• A hole is drilled in the concrete floor slab, an anchor sleeve is driven into it and a pin is screwed into it.
• The lower (under the joist) nut with a washer is screwed onto the stud. A hole is drilled in the joist with a hammer on top.
• The lag is put on the stud, so that the nut and washer are on its lower side. By rotating this nut you can adjust the position of the joist. The second nut (top) is necessary to fix the log at the set level.

As you can see, modern construction industry offers ever new alternatives to traditional construction technologies. Adjustable – shining example such an alternative that makes it easier and cheaper to install and repair floors.

Innovative surface leveling techniques have been developed to optimize finishing times and reduce labor costs. A fairly young innovation - adjustable floors provide finishers and property owners with a significant number of technological and consumer advantages. With their help, the preparation of the rough surface is carried out quickly, simply, and ideally, which does not require professional skills from the performer.

Universal designs of adjustable roughing bases are used for arranging premises of any purpose, area, configuration. For old buildings with not very reliable floors, for light country cottages made of wood or foam concrete, the ability provided by this technology not to load the floor with a multi-ton concrete screed is an excellent option. For new buildings with low ceilings This is an opportunity not to reduce the height of rooms that are not very spacious.

Benefits of adjustable screeds

Structurally, progressive floor leveling systems are a solid, dense flooring with mechanical devices, with the help of which the floor is adjusted in the horizontal plane. Main features of this technology:

• Floor systems with adjustment devices can be installed in a couple of days.
• Durable adjustable floors can be installed with your own hands by a person who is installing a floor for the first time.
• Between the rough surface and the overlap remains useful technological gap, increasing insulating qualities. In this space, you can lay communications, supplement the insulation by laying synthetic or mineral insulation.
• The floor plane can be raised to a level of up to 20 cm, the thickness of the leveling layer can be reduced to 3 cm, and a multi-level floor can be arranged with one or more podiums.
• Rigid fastening of the leveling system elements to the concrete or wood base is provided.
• It is possible to refuse the underlay traditionally used when laying parquet and a number of other types of floor coverings. This is another economic advantage, reducing the cost of the floor by almost half.
• Once the clean, dry installation of adjustable bases has been completed there is no need to delay finishing such as, for example, due to waiting for the screed to completely cure.

According to experienced foreign users, adjustable floors will serve faithfully for half a century. The presence of a ventilated cavity will also eliminate the possibility of premature “aging” of the floors, and the floor will not be damaged in case of emergency floods.

An additional layer of insulation can be placed between the joists.

Floors constructed using this technology will not squeak annoyingly or warp, as happens with outdated adjustment of floors along joists, which is done using loose wood chips or sand.

Progressive systems supplied from abroad and produced by domestic enterprises are distinguished by another important advantage - affordable price, almost a third of the money invested in leveling can be saved by abandoning the cement-sand screed.

The immaculately leveled surface can be raised to any level

Two types of adjustable designs

According to design features and specific application, adjustable floors are divided into two types:

1. Systems consisting of dense, durable chipboards, adjustable in the horizontal plane using special devices made of heavy-duty plastic. They are preferred to be installed in new buildings, since the power of leveling with slabs raises the floor surface to a minimum height of 3-5 cm. Despite the insignificant amount of technological space under the raised floors, it is still possible to lay cables and thin insulating material.

Adjustable floor systems, plywood leveling

2. Practical floors with adjustable joists, the installation technology of which is similar standard device multilayer cake with beams. The difference lies in the strong fixation of the elements to concrete or wooden base and in precise adjustment of horizontal lines. This type of floor is used for furnishing apartments in old buildings and luxury housing with planned “underground” laying of communication pipelines and cables.

Adjustable floor installed on joists

One of the valuable priorities of these leveling structures is the reliable fixation of the entire system to a wooden or concrete base.

More precisely to base material Threaded anchor devices are firmly attached, the rotation of which around its own axis allows you to increase and decrease the height of the subfloor level. Easy-to-install adjustable floor supports secure:

• to wooden floor beams using self-tapping screws;
• to the hollow inside concrete slabs and to the surface with a concrete screed with polypropylene hedgehog dowels for brick and concrete;
• to monolithic base floor made of concrete with dowels and nails.

Anchor devices perform several functions simultaneously: they take on part of the load, provide adjustment and a strong connection between the structure and the ceiling.

Installation of floors with leveling plywood

A distinctive feature of this technological option is that the bolts are inserted directly into holes drilled in the plywood decking, in DSP plate or in gypsum fiber sheet. Here is the order of work:

• from the back side, bushings are inserted into the drilled holes, inner surface which threads are laid, the pitch between the holes depends on the expected load;
• then stand-up bolts made of durable polymer are screwed into the holes with bushings;
• the assembled element is installed on the ceiling;
• bolts are attached to the base;
• by rotating the rack-bolts around the axis, the horizontal plane is leveled;
• the remains of the bolts rising above the surface are cut off;
• then the next layer of flooring is laid overlapping.

The butt seams between the slabs of the first layer of flooring should not coincide with the location of the seams of the second layer.

Laying a sub-level adjustable plywood floor

Any type of finishing floor covering can be laid on top of the leveled surface.

Installation of floors with adjustable joists

Both types of leveling systems are produced by the company dnt: the adjustable floors it supplies to the market are successful. In the manufacturer's product list you can select ready-made system for any design floor height, regardless of the type of base and material chosen for finishing.

The company's leveling systems with joists are raised and lowered by rotating the post bolts.

• anchor bolts made of heavy-duty polymer are screwed into threaded holes in the joists;
• logs with a step depending on the design characteristics of the floor are installed on the floors;
• a hole is drilled through each anchor wooden beam or in a concrete mass, a dowel-nail or self-tapping screw is driven into the resulting hole;
• the logs are leveled by checking their position with a level gauge or laser device;
• The excess plastic bolts are cut off and the subfloor is laid on top.

The complete set of structures prepared for installation is selected depending on the strength characteristics of what is planned for installation flooring, on the distance between the logs and the section of the timber, on the thickness of the flooring.

Installation of adjustable floor joists

Making your own control anchor

Basically, knowing design features, both leveling systems can be made by yourself. After all, in hardware store you can purchase all the components: flooring - thick plywood, gypsum fiber board, chipboard; logs are ordinary wooden beams. It will be problematic to buy only polymer bolts with large threads. However, you can with my own hands make an anchor for an adjustable floor.

To make an analogue of the control device, the master will need:

• drive-in anchor;
• hairpin;
• two nuts and washers each;
• metal plate.

The stud will act as a support bolt that is secured to the base surface via a drive-in anchor. The support for the beam will be a metal plate attached to the stud with a bolt and a pair of nuts. This nut will make adjustments. Another nut and bolt are needed to secure the beam from above. To ensure that the upper nut does not subsequently interfere with installation finishing material, a groove is made in the joist on top. The excess pin is cut off after alignment.

By analogy, you can make a control device yourself

An adjustable leveling system made with your own hands or purchased at a hardware store will significantly reduce the budget for repairs or finishing in a new building. Quick, clean installation will eliminate wet, messy and rather expensive processes.

An adjustable plywood floor can be raised to heights of 3-5 cm or 15-19 cm, depending on the designs of adjustable supports used. If you need to raise the floor small height 3-5 cm, while it is impossible or not possible, given the permitted load, to arrange a floor screed; an adjustable floor is made of plywood with plastic racks. To lift to a height of up to 19 cm, steel studs with supporting washers are used to support the plywood.

The design of an adjustable plywood floor does not require the use of wooden joists, and the adjustable bushings are screwed directly into the plywood (plastic bushings) or pass through the plywood (metal support studs).

Adjustable floor construction made of plywood with plastic studs

The adjustable plywood floor on plastic studs can be raised to a height of 3 to 5 cm. This is enough for laying under the floor engineering communications plumbing, low-current and power electrical wiring.

For an adjustable plywood floor, moisture-resistant plywood with a thickness of 12 mm is used. Plywood is laid in two layers with offset. The first layer of plywood is directly adjustable in height using bushings, the second layer strengthens the floor structure.

The floor level is adjusted using a plastic post bolt and a bushing inserted into a hole in the plywood. 13 holes are made on a sheet of plywood measuring 1525x1525.

When calculating the finished floor level, the following are taken into account:

• 5 mm support washer;
• 2 layers of plywood 12mm each;
• Total 24.5mm.

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Adjustable plywood floor construction on metal studs

A metal pin can be used to support the plywood sheets.

• At the base of the floor, the stud is secured with an anchor dowel.
• The plywood is supported by a large metal washer, the height of which is adjusted with a special nut.
• The plywood is secured on top, also with a washer and nut.
• A gap of 5 mm is left between the sheets of plywood of the first layer.
• The second layer of plywood is laid offset and attached to the first layer with self-tapping screws.
• A 5 mm gap is left between the wall and the second layer of plywood for ventilation.

A new technology for many of our compatriots, it 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: to be able to choose from among the numerous options for flooring the one that will be optimal in this particular case.

Finish floor coverings are installed according to wooden joists(in case of using floorboards) or by solid base from sheets of plywood or OSB (in the case of using laminate or soft coverings).

Very important point During the construction of any floors, the load-bearing surface must be located in a strictly horizontal position.

It is very difficult to achieve such a result with the help of fixed logs; you often have to use various wedges or pads to level the spatial position. These wedges may fall out due to improper fixation or for other reasons, and 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.

Adjustable floors with your own hands - a diagram of one of the possible options

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

Adjustable floors consist of plastic stud bolts or metal studs, floor joists, or plywood sheets. Many modifications of regulatory systems are made, but there are no fundamental differences between them. By rotation threaded connection there is a smooth lowering/raising of structural elements, in this way you can 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 adjustable floors

Types of adjustable floors	Characteristics	Illustration
WITH plastic mechanism regulation	They can be sold assembled with lags or as separate kits. Factory floors are much faster to install; they have pre-cut threads in the joists, so 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. It is recommended to install logs in increments of 30÷40 centimeters; specific values ​​must be selected taking into account the expected maximum load on the floor.
With metal adjustment mechanism	Instead of plastic connections 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 log increases, it is possible to create complex designs floors taking into account the specific layout of the rooms. Disadvantage: installation time increases significantly.

Both joists and slabs can be adjusted. The second option is used only for laying soft flooring or laminate; the first option can be used for all types of finishing floor coverings.

If you wish, you can make adjustable floors yourself; this option has its undeniable advantages. The main ones are significantly lower cost and the ability to select log 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.

Technology for installing factory adjustable joists on plastic bolts

Initial data. Load-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 number of joists. The floors in the bathhouse do not have a large load; the distance between the logs can be increased to 45 centimeters.

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

Step 3. Cut the joists to the required length. The length of manufactured factory logs in most cases is four meters. Carefully consider how to mark the joists to minimize the amount of 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 is a risk of cracks forming under loads.

Step 4. Place the joists near the marked lines. For installation you will need a small drill with a hammer drill, a special wrench for screwing in bolts, a hammer for fixing dowels, a screwdriver, a chisel and a hammer.

Step 5. Place the first joist in a vertical position and screw plastic bolts into the threaded hole. Place the bottom ends of the bolts in 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 reserve in length, it will prevent you from driving the dowel completely.

Step 6. Attach the dowels, but do not drive them all the way in. The dowel should not interfere with the rotation of the plastic bolts. Use a long level to set correct position lag If the joist is installed, firmly fix the dowel. Continue to install the logs in the marked places one by one, constantly monitoring their position with a level.

Manufacturers offer this installation algorithm, as do many builders who receive wages not based on output, but hourly. Those who work from the workings do things differently. How? They take the hydraulic level and hit the zero level of the log on two opposite walls. Then nails or dowels are driven in these places (depending on the material of the walls) and the ropes are pulled. The ropes are tensioned so that they are located at the ends of the joists. If the length of the room is not greater than the length of the logs, then you will need two ropes. If the logs had to be connected, then three. The rope is tensioned only after the logs have already been placed at their 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 to not only significantly increase the speed of installing 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? There is a high probability that the position of the first log has deviated from the desired level by one millimeter. It's not much, it's okay. But the fact is that the next checks will be done taking into account this deviation, again the probability of an error of a millimeter appears, and so on in increasing order. It is for this purpose that a template is made if you need to cut a large number of identical parts, rather than taking dimensions from each finished part one by one. IN in this case the rope acts as a template.

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

Floor with plastic bolts - check

Prices for plastic bolts

plastic bolts

Video - Installation technology for adjustable floors

The main advantage of such floors is that the stability of the fastening is significantly increased due to the increase in the area of ​​the lower stop. Disadvantage: the deadlines increase, the inability to do the work yourself.

The logs are fixed to the U-shaped plates using self-tapping screws; the height of the logs is adjusted using a series of vertically located holes on both sides of the plate.

Step 1. Using a blue rope, mark the locations of the floor joists. Calculate required amount materials and additional structures.

Step 2. Determine the floor level, make marks on the walls. Arrange along the lines metal plates and lags. The width of the plates must correspond to the lag tire. The distance between the plates depends on the parameters of the log; forty centimeters is enough for a bath.

Step 3. Use dowels to secure the plates to the concrete base. Immediately hammer in the dowels until they stop, then it is very difficult to tighten them - the log lies on top and prevents access to it. If the metal plates move a little during fixation, it’s okay. When installing the joists, slightly bend their side parts in the desired direction.

Fixing the bracket

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

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

Installing joists on metal studs

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

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

Step 2. Make calculations based on the number of joists, studs, washers and nuts. The recommended distance between the studs is 30÷40 centimeters. Prepare all materials, additional elements and tools for the work.

Step 3. Mark the holes in the joists for the studs; they should all lie on the line of symmetry. First drill in the designated places through holeØ6 mm for the stud (if the diameter of the stud is different, then the corresponding hole must be drilled). On the front side of the joist, use a feather drill to drill a hole for the diameter of the washer. 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. Place each joist in turn on the broken parallel lines on concrete screed. Very carefully, one by one, mark the future installation locations of the anchor threaded elements for each joist. Make sure that the joist does not move. For marks, use a drill or an ordinary pencil. For a drill, you need to take a drill with a pobedit tip. The places are marked - take away the lag and drill holes in the concrete. The dimensions of the hole must correspond to the dimensions of the anchors.

There is a second way to mark holes for anchors; it takes more time, but completely eliminates the possibility of errors. It's done like this. First, you need to mark only the two outer holes for the anchors, screw the studs into them on two nuts, and fix the joist in the desired position. Now during further marking the lag will not move anywhere. In this position, you can immediately drill holes for the anchors to the full depth. The work is completed - the joist is removed, all the studs are screwed into place. This procedure will have to be performed with each lag; labor productivity is reduced by half. But you must make your own final decision on the marking method, taking into account the condition of the concrete subfloor and your experience in performing this type of work.

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

Video - How to tighten hairpins

Step 6. Place the logs on the studs one by one, using a wrench of the appropriate size by turning the bottom nut left/right to align the position of the logs. We have already told you how this is done. Keep in mind that the thread pitch of metal nuts is much smaller than plastic ones. In some cases, you will have to twist for quite a long time, which is tiring. Moreover, the position will be uncomfortable: you will have to sit on your knees and bring the key from the bottom of the joist.

Step 7 The logs are exposed - you can start fixing them. Use a washer and nut and 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 the joists, do not damage the integrity of the lumber with the saw blade.

Installing floors with leveling plywood

This subfloor is only suitable for laminate or soft flooring. For installation, you need to buy a set of factory-made elements; the work is more difficult to complete.

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

Photo - drilling a hole in plywood

Step 2. Insert threaded bushings into the holes on the bottom side, secure them with small self-tapping screws; they should not turn when adjusting the floor height. Manufacturers provide four places for fixing the bushings, so many are not needed, just secure it with two self-tapping screws.

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

Step 4. Screw in all the plastic bolts, turn the sheet of plywood into the desired position. Screw the bolts in the same number of turns. After installing the first sheet of plywood, pay attention to what level the bolts are located. Try to screw the bolts into the next sheet of plywood in the same position.

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

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

Do not use chipboard, OSB or other materials instead of high-strength plywood, although some manufacturers give such recommendations. Pressed materials react very poorly to point multidirectional forces; in these places they quickly lose their original load-bearing capacity. Namely, such loads are present in the places where the plates are adjusted. Even though plywood costs much more, its price will pay off during the operation of the floor.

Name	Size	Variety	price, rub.
FC plywood, unsanded	4x1525x1525 mm	4/4	RUB 247.00/pcs.
FC plywood, unsanded	6x1525x1525 mm	4/4	RUB 318.00/piece
FC plywood, unsanded	8x1525x1525 mm	4/4	RUB 448.00/piece
FC plywood, unsanded	10x1525x1525 mm	4/4	RUB 560.00/piece
FC plywood, unsanded	15x1525x1525 mm	4/4	RUB 738.00/piece
FSF plywood, unsanded	9x1220x2440 mm	3/3	RUB 1,048.00/piece
FSF plywood, unsanded	12x1220x2440 mm	3/3	RUB 1,345.00/piece

Prices for anchors for sheet materials

anchors for sheet materials

1. Do not forget to leave 1÷2 centimeter wide gaps around the perimeter of the room near the walls for natural ventilation and expansion compensation wooden structures. These cracks are then covered with baseboards and become invisible.

   

2. For lags, select only quality lumber with a minimum number of knots. Large cracks, visible fungal diseases and mold damage are not allowed.

   

3. Do not drill holes for studs on knots; it is better to move them a few centimeters. The fact is that wood, if the integrity of a healthy knot is damaged, significantly loses its strength. The installation of adjustable floors requires the presence of forces not over the entire area of ​​the joists, but only at several points. This feature requires wood to have increased strength indicators. This remark also applies to the load-bearing base of the floor; point forces also act on it; the load per square millimeter increases significantly. Accordingly, concrete must be strong; during its production, it is not allowed to deviate from existing construction standards. Any deviations in strength will lead to the fact that over time, the base will be destroyed under the stops, the floors will begin to sag and, as a result, it will creak very unpleasantly. It is impossible to eliminate these sounds without dismantling the entire structure.

   

4. The higher the level of the adjustable floor above the ceiling, the more it “sounds”. To reduce noise levels, 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 flooring options only as a last resort. Practice shows that the number of disadvantages of such structures exceeds the number of advantages. The cost of adjustable joists alone can exceed the total cost of flooring made with ordinary traditional way. Decide what is faster to do: lay several joists at once or drill dozens of holes in them and then “screw them in” with bolts and nuts.

Video - How to make an adjustable floor