The device of the floor in a wooden house: tips for laying and building two types of structures

The device of the floor in a wooden house

When pronouncing the word “floor”, most of us represent the final floor covering, without thinking that under it, as under the icing of a pie, several layers of the filling are hidden – complex engineering structures. A particular device of the floor in a wooden house depends, first of all, on the purpose of the house and its individual rooms, on the quality and capabilities of the bearing base, that is, flooring or soil. Yes, and the highest quality ceilings will not be able to ensure the durability of the floor, if the base for them was not properly prepared and does not have the required physical and mechanical characteristics.


  • How is the floor of a wooden house
  • Bearing base – overlap
  • The device of a wooden floor on the ground
  • Single wood floor
  • Double wooden structure

How is the floor of a wooden house

A structure located between the base and the final flooring is called a subfloor or subfloor. The device of the rough floor can be different, but in any case it is a combination of the same constituent elements:

  • the underlying layer – perceives the load from the coating, transfers it to the walls and evenly distributes along the base; it can be a supporting slab or prepared in accordance with the requirements of the soil;
  • leveling layer – a dense layer that levels the surface of the underlying layer; if a floor slope is planned, it is also created at this stage using a screed or other techniques;
  • intermediate layer – a layer connecting the coating with the underlying floor elements;
  • insulation layers – provide heat, moisture, and sound insulation, and their location depends on how the floors will be arranged in a wooden house and which of the functions will be assigned to the insulation layer.
How is the floor in a private house

Options for laying floors in a wooden house

So, wooden floors in a private house are equipped on a load-bearing basis, the role of which can be played by soil or interfloor, basement or basement.

Bearing base – overlap

Floors arranged on interfloor ceilings are practically not affected by significant changes in temperature and humidity. After all, the microclimate in the rooms shared by them on the first and second floors is almost equally stable enough, and therefore the floor structure does not need additional thermal or vapor barrier. For this type of floor, noise isolation is more important and, if there are bathrooms on the second floor, you should take care of enhanced protection against possible leaks.

In the case when the floor in a wooden house separates the warm residential floor from the unheated basement or basement, special attention should be paid to its heat protection. Since the flow of warm air is directed from top to bottom, from the living room to the basement, the protective vapor barrier should be placed on top of the heat insulation, directly under the finish floor covering. Otherwise, the heat-insulating layer will be moistened with condensate and lose heat-shielding properties..

The device of a wooden floor on the ground

In the construction of prefabricated wooden houses, the installation of a wooden floor on the ground is very popular: they are cheap, and their design is simple. Also, this method of flooring is widely used in basements, if they are provided for by the project, and in utility buildings for various purposes. Most often in wooden houses, floors are mounted on supporting poles.

Important: Ground floors can only be used on dry soils! The wooden floor on the supporting poles is installed only in those cases when the special supporting beams for laying the floor are not laid in the walls of the wooden log house; The floor on the supporting posts is a floating structure independent of the load-bearing walls..

The installation of the wooden floor on the supporting poles is carried out in the following sequence. First, a layer of turf is removed from the underground space to a depth of at least 50 cm, and a layer of crushed stone, gravel or river sand is poured into the cavity formed. The backfill layer is watered with water and carefully compacted using a special ramming technique. After completion of compaction, the level of backfill should rise about 20 cm above the ground level around the house.

The device of a wooden floor on the ground

In wooden houses without a basement, floors are often equipped on pillars

The next step is the installation of support pillars. It is best to use bricks as the material for the support posts, not red silicate, but red. The cross-sectional area of ​​the support column to ensure the stability of the entire structure is selected depending on its design height: the higher the posts, the larger the cross-sectional area will be required. If the height of the brick support pillars does not exceed 250 mm, they are laid in one and a half bricks, and at a height of 250 mm and above – in two. Sometimes concrete support columns are installed with overall dimensions from 400×400 mm to 500×500 mm. First, install poles around the perimeter of the house with a step of 50-60 cm, carefully checking the horizontal level, because the perfectly even surface of the future floor depends on it. Having completed the installation of external supports, mount the internal. Their step, depending on the constructive solution of the future floor, can be 70-100 cm.

Important: Sometimes during the construction of wooden country houses for seasonal living, internal support poles are not installed, and the necessary floor strength is provided by special thick beams, the cross-section of which is calculated when designing a house.

After completing the installation of supports, their ends are protected by a layer of waterproofing, usually this function is performed by 2-3 layers of roofing material, and they begin to lay the supporting beams. The load-bearing beam is a solid log or beam of the appropriate length, but if such lumber is not there or for some reason it cannot be used, shorter beams can also be dispensed by joining them on the pillars of the supports. When exposing the beams, they again carefully calibrate using the level horizontal, if necessary, level them using wooden gaskets and wedges. When all the beams are exposed, the position of the gaskets and wedges should be fixed with nails. The supporting base on the support beams is ready, now you can lay on it a draft floor of wood, which can be single or double.

Important: If a wooden house is supposed to be used as a summer house in the warm season and in winter it will not be heated, to prevent the displacement of support pillars due to freezing of the soil, a higher backfill should be made and its top layer made of coarse gravel.

Single wood floor

Simple in installation and operation, a single wooden floor is most often laid in cottages, where people are constantly only in the warm season. In wooden cottages of a small area, they do not even always create a structure from supporting pillars, but simply mount the supporting beams designed for arranging the floor in the outer walls of the log house.

Laying the floor in a wooden house of a small area is performed in the following order. If the supporting support beams are initially provided for in the construction of the external walls of the log house, then logs are necessarily laid between them and then single-floor boards are laid on them.

Single wood floor

Laying the floor in a wooden house of a small area is carried out on the supporting beams mounted in the walls of the log house

If the project of a wooden house provides a single floor on the supporting poles, then the supporting beams, as a rule, are laid taking into account the requirements of this particular type of floor in the process of creating a supporting structure. That is, with a distance between the support columns of 80 cm, the load-bearing beams with a section of 100×100 mm are laid, and if the distance between the supports is 100 cm, then beams are laid with a section of 120×120 mm.

If the system of load-bearing beams meets these conditions, then directly on top of them you can lay the floor from the grooved board. If for some reason this condition is not met, then on the supporting beams, first stack a grid from a log and only floorboards are laid on it. Logs are a wooden beam with a section of 50×50 mm or 60×60 mm, which is laid with a grid on top of the support beams. The step of laying the log is chosen depending on the thickness of the board intended for laying the floor. If the thickness of the tongue-and-groove board intended for flooring is 28 mm, then the logs are laid at a distance of 50 cm, and with the thickness of the tongue-and-groove board 38 mm, the lag step is increased to 60 cm.

Having laid out all the lags at the base of the beams, with the help of wedges and gaskets, the lag system is set according to the level and finally firmly fixed with nails. Directly on the lag system, a black floor is laid from an unedged board or from a finished sheet pile. Any floor covering is laid on the rough floor: linoleum, laminate, carpet. The finished floor from the tongue-and-groove board is usually cycled and covered with several layers of varnish or other composition for covering the floor.

Single wood floor

Installation of a single draft wooden floor

Single wooden floors are laid in country wooden houses and other temporary or utility structures, when the thermal insulation characteristics do not play a role, and the choice of option is determined by the low cost and speed of installation. In capital wooden houses intended for permanent or periodic residence throughout the year, including in winter, it is recommended to equip warm double wooden floors.

Double wooden structure

More complex compared to a single double wooden floor, it is a multilayer structure consisting of a rough flooring made of unedged boards, vapor-insulating, heat-saving and sound-absorbing layers and, finally, a curtain finishing board made of grooved boards. This capital floor design will keep a pleasant cool in the house in the hot summer and provide a comfortable microclimate in the winter cold.

The laying of the wooden floor of the double insulated structure begins with laying on top of the supporting beams of the system of so-called cranial beams lying on the supporting pillars. On the cranial beams and lay the rough floor, fitting boards tightly to each other .. For the rough floor, any boards with a thickness of 15-45 mm are suitable. This can be a low-grade board, unedged board, croaker, but it must necessarily be from coniferous wood, and best of all from larch. That is, it must be wood with a high resin content, pre-treated with an antiseptic.

Double wood floor

Fastening of the board and rough and fair flooring is done with nails at an angle of 40-45 ° at a distance of 15-20 mm from the edge

Having laid the draft floor, a heat-protective layer is applied to it. It can be any modern heat-insulating material, for example, mineral wool or polystyrene. But in the tradition of wooden housebuilding, as a heater of the subfloor, they have long used a well-proven mixture of wood sawdust and clay in a 1: 1 ratio moistened with a small amount of water, which is applied with a layer thickness of 35-50 mm. On top of the dried clay-sawdust layer lay a layer of small or medium-sized expanded clay. The thickness of the expanded clay layer should be 5-10 mm, but at the same time, a gap of at least 10-15 mm should remain between the insulation layer and the final finishing floor.

If desired, any polymer film can be laid on a thick layer of thermal insulation, which will perform the function of vapor barrier and you can proceed with laying the final floor from the grooved board. The board of the rough and fair flooring is nailed to the logs or to the cranial bars with nails at an angle of 40-45 ° at a distance of 15-20 mm from the edge on each side. The flooring board is laid tightly and the gap between two adjacent boards should not exceed 1 mm, otherwise, in case of wood drying out, too wide gaps may appear in the floor.

If you plan to leave the final floor as a finishing coating, cycle and then varnish, then for fixing it to the logs it is better to use special nails without caps, hammering them into the board with a metal damper to a depth of 3-5 mm. If it is planned to lay the parquet, then the second, the so-called finishing flooring can be made of less quality boards and then, following the technology, lay the parquet.

Considering that the floor structure on the supporting posts is not connected by rigid ties with other structural elements, in order to prevent shock loads on vertical partitions and walls, gaps of about 20 mm wide are left at their junctions. The gaps are filled with special gaskets made of elastic materials and then decorated with a plinth.

Double wood floor

At the junctions of the floating floor structure to the walls, gaps of about 20 mm wide are left

To ventilate the space between the layers of the double floor in the corners of the finishing floor, through holes with a diameter of 50-60 mm are made, which are closed with decorative grilles, visors, slightly raising them by 10-15 mm above the floor so that during cleaning no water gets into the underfloor. For more efficient ventilation, some vents in the floor are not enough, therefore, special ventilation windows or hatches are also provided in the basement of the house.

The proposed technology of laying the double floor is suitable for arranging floors in the hallways, living rooms, study and bedrooms of a wooden residential building. In kitchens and bathrooms, when arranging floors of this type, more attention will need to be paid to sealing the waterproofing of technological gaps at the joints of the floor and wall structures.


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