Floor on joists in a private wooden house: what the structure looks like

Installing a floor along logs involves installing and fastening beams at intervals of 50-60 cm or a little more. Insulation, hydro- and vapor barriers are usually laid between them. The structure of the floor may differ slightly depending on the base. A description of the features of this design and instructions for its construction can be found below.

Lag requirements

As a rule, the floor on logs in a private house is made of wooden beams, the cross-section of which is a rectangle. Moreover, its length should be 1.5-2 times greater than its width, as shown in the diagram.

There are several important requirements for the material, among which are the following:

• wood moisture content is within 12% - it is necessary to ensure that storage conditions are carefully observed;
• thickness from 20 to 50 mm, depending on the load;
• the material is treated with an antiseptic.

Floor installation

The construction of floors on joists depends on the base on which they are installed. In private houses they are usually placed on concrete, on the second floor - on the ceiling. In bathhouses and other outbuildings it is allowed to lay directly on the ground surface.

On the ground

Wooden floors on joists are one of the simplest installation methods, especially if laid on the ground. In this case, the logs are placed on brick columns, which serve as a columnar foundation.They are placed at the same interval, which depends on the thickness and length of the logs. Usually they plan a distance of 50 to 100 cm with mandatory waterproofing, as shown in the diagram.

The design of the floors involves installing brick pillars directly into the ground. They are pre-aligned using a building level so that each column has the same parameters, i.e. height and surface area. Next, a layer of cement is poured onto it and logs are installed. In this case, several rules are observed:

1. A waterproofing material, for example, roofing felt, is laid between the columns and the crossbar.
2. Next, lay the timber, retreating from the surface of each wall at least 30 mm.
3. The flooring is laid on logs so that there is a minimum distance of 3 cm between each wall and the timber.
4. Thermal insulation must be provided - sand, crushed stone or expanded clay are poured between the wood.

On a concrete base

In permanent buildings, heated floors are laid on wooden joists directly on a concrete base, i.e. on a monolithic foundation. The technology involves fastening with dowels. They are screwed into the base, and logs are installed on top through a rubber compensator. Bitumen or bitumen-impregnated cardboard is used as waterproofing. On top of it is a wooden board and finishing.

Warm floors are laid along joists in a wooden house at intervals of 50-60 cm. Although if you plan to use tiles as a finishing coating, then the step is reduced to 30 cm.

On the ceiling

With this method, installing a plank floor along joists is even simpler, because there is no need to install brick columns on the floor. Installation proceeds in the same way as described above. You can take this diagram as a basis.

Step-by-step instructions for laying the floor

Floors on wooden beams of the 1st floor are laid in several stages. First, you need to prepare materials and make calculations, then process the base and lay the logs directly on the subfloor or on brick pillars. The step-by-step instructions look like this:

1. Using a tape measure, determine the length and width of the room, calculate the number of logs and their length. Make markings, checking the dimensions several times to avoid mistakes.
2. The floor on the joists in the house begins to be laid from a beam running along the wall. If there is already a subfloor, the logs can be laid directly on it. To do this, use metal corners with special holes (perforation). One end of the log is placed according to a mark on the wall, and the other is exactly the same. Correct operation is checked using a building level.
3. Stretch the rope between the outer joists. It creates a guideline against which all other beams can be placed. The position is controlled by level - the difference should be within 2 mm.
4. If the floor structure on joists involves the use of insulation, you will also need to install waterproofing and vapor barrier. The interval between the beams is calculated in advance, focusing on the size of the insulation. Mineral wool or polystyrene foam, as well as bulk materials, are often used. For good air exchange, it is important to leave a small gap of 5 cm, as shown in the photo.
5. After covering with a vapor barrier, this is what the wooden floor will look like from above.

This is followed by finishing, such as parquet, laminate or board. Installation is quite simple if you carry out the preliminary calculations correctly. The technology for installing floors using joists is universal and can be used both in residential premises and in outbuildings.