Draft floor in the house itself

Beautiful flooring is half the success of building a new house or repairing an old one. Today there are many options for arranging the flooring used, anyone can choose the right one according to the wallet and taste. But whatever coating is chosen, it is important to lay it on a flat surface. In order to be able to perform the insulation, it is important to know how to make a rough floor in the house with his own hands.

Lag mount

Lag mount

Installation of the subfloor in a wooden house or made of brick does not have any particular differences. Most importantly, fix the lags correctly. For wooden houses, this work is carried out according to its technology.

To fix logs it is necessary on the base of the foundation or the grillage. In this case, the width of the base (the protrusion of the base on which the lag will be laid) must be more than 10 centimeters. If there is not enough space, you can make cuts in the lower log or timber. Before this, the lag is laid on the foundation and the mark of the future cut is made in the wall.

Note! Lags are placed only on the foundation or grillage with a waterproofing layer. This will prevent the wood from rotting. In addition, all wooden parts of the subfloor must be pre-treated with an antiseptic.

It is necessary to make an additional strapping of the boards around the perimeter, and already fasten logs to it. When installing it is necessary to make a distance from the walls of at least two centimeters. The lags themselves are fixed so that they just hold in their places and do not “drive”. Make a hard mount is not necessary.

The step and size of the lag is chosen depending on the future load. As a rule, the pitch is 40–60 cm. The cross section lag at a small load can be 15 to 10 cm, with a large load of 15 to 20 cm. If there is no material with suitable dimensions, you can use thinner ones. In this case, the lagging step is reduced to 25–30 centimeters.

Installation of subfloor

Making a rough floor

Rough wooden floor can be made in different ways, but we consider the one that is made in the form of a multi-layer "cake". The process itself takes place in several stages.

  1. Mount the cranial bar. This material has a small cross section (usually 4 × 4 cm). The beam is mounted on the sides of the lower part of the log. Instead of a cranial lumber, you can use a regular board, it is important that it protrudes at least 4 cm from each side of the lag.
  2. We lay the boards. They are simply placed on the cranial bar (or board, fixed lag down). To beat them or somehow not to fix in another way. Their main goal is to keep insulation on itself.
  3. We carry out waterproofing. It is better to use any suitable film waterproofing material. He must close all the logs and laid boards. Also, the entire height of the future subfloor (the distance from the boards laid on the cranial bar and the future floor surface) is also waterproofed.
  4. Mounted layer of insulating material. Insulation fit between the lags. It is better to fill all the space, leaving a couple of centimeters from the top of the lag for ventilation.
  5. You can make a vapor barrier. The layer of material as well as in the case of waterproofing devices, should cover the entire surface, going a little on the walls (the excess can then be cut off).
  6. Make sure that there is a gap for ventilation (at least 2 cm). If the distance from the top of the lag to the vapor barrier is not enough, then the counter rails of the required height are nailed along the lag.
  7. Now you can lay the floor. For this, either boards or sheet material are used. The latter option speeds up the work. Sheet chipboard, OSB or plywood, laid in several layers, perfectly withstand the load and make the surface of the subfloor perfectly flat. If we talk about laying sheets of plywood, particleboard or OSB, then they are mounted in several layers. The location of the seams between the layers should not be the same.

Treatment of timber with antiseptic

During the installation of the subfloor it is necessary to remember some nuances. Firstly, all wooden elements must be pre-treated with an antiseptic. This should be done at least twice at intervals to absorb the funds. It is also necessary to ensure that the wood used is well dried. Otherwise, the rough floor will start to warp.

Secondly, laying the top layer of the subfloor (boards or sheet material) must be at least two centimeters indented from each wall. This space is necessary so that the tree does not deform when the temperature or humidity changes. After laying the space between the wall and the boards (or sheet material) can be sealed with insulation. In the future, this gap will be closed with a plinth finishing coating.

Floor insulation

You can install a rough floor in a wooden house by yourself. It does not require much knowledge in the joinery business. It is important to closely monitor the material used and do all the steps carefully and without haste.


This video shows how to install the subfloor:

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