When constructing a private house, special attention should be paid to vapor barrier of the ceiling, floor, walls and roof. If this important step is skipped, the structural elements of the building will not last long. We will talk further about why it is important to arrange a vapor barrier in a private house and how to do it correctly.
The need for protective films
A special film that protects the heat-insulating material from moisture is included in the “pie” of the walls or the roof. The fact is that due to the difference in temperature, especially in the winter, on the street and in the house, indoors, condensation settles on the walls and ceiling. As a result, the heat insulator gets wet and stops performing its functions. The house is getting cold. In addition, moisture leads to damage to the structural elements of the building.
Varieties of vapor insulators for walls
There are only three main varieties of films designed to protect mineral wool or expanded polystyrene from moisture:
- Standard. The cheapest and not particularly durable form of vapor barrier. In most cases, this is an ordinary thick plastic film.
- Foil. It is more expensive than polyethylene, but at the same time, in addition to the vapor barrier itself, it performs another function - it reflects heat back to the room. Owners of country houses are very often interested in which side to install the vapor barrier on the walls and ceiling. This question usually arises in relation to this variety. The way this film is actually mounted is discussed below.
- Membrane It features a limited vapor barrier. This allows you to control the removal of moisture from the room.
What are vapor barrier for roofs
To protect the walls of attic and attic rooms from condensation, membranes are usually used. In this case, you can choose:
- Perforated. This variety is a reinforced film or combination fabric.
- Three-layer superdiffusion. It differs in that it has no holes. Recommended for use in dusty environments.
- Porous. It is applied where there is no dust. In such a film there is simply a huge number of interfiber pores. Dust clogs them. As a result, the film ceases to fulfill its functions.
- Two-layer film. A cheaper variety of a three-layer superdiffusion membrane. In such films, one of the protective layers is missing.
Also, for vapor barrier of walls and ceilings, rolled or sheet material can be used. There is no particular difference in their cost.
Vapor barrier: price
Depending on the variety, the cost of the material may be different. For example, an ordinary vapor barrier plastic film costs about 500 rubles per roll. The folded version will cost about 1400-1800 rubles. A three-layer diffusion membrane will cost about 4000-5000 rubles. The popular vapor barrier Izospan will cost about 800-1000 rubles. per roll. These prices are valid at the beginning of 2015.
Vapor isolators "Izospan"
At not too high cost, this is one of the most reliable and, as already mentioned, popular varieties of protective material. There are several types of such films as vapor barrier "Izospan":
- Class A. Designed for internal structural elements.
- Class AS. This is a three-layer membrane, which is usually used in ventilated facades and to protect roof structures from under-roof condensate.
- Class B. Universal two-layer version
- Class C. Hydro and vapor barrier material.
- Class D. Also designed for waterproofing and vapor barrier structures. It can be used to protect against capillary moisture.
- Class SL. It is a connecting mounting tape.
Calculation of vapor barrier
Of course, before you go to the store to buy a film, you need to do all the necessary calculations. Performing this procedure is completely straightforward. All that needs to be done is to calculate the area of all structural elements of the house requiring protection. The calculation is made taking into account the width of the vapor barrier film and the necessary overlaps.
Installation of vapor barrier film on the walls
Next, consider how to properly install this protective material. Including we will figure out which side to install the vapor barrier. The “pie” of the walls is arranged in a few steps:
- Preliminarily, a crate is packed on the surface. They usually make it from a beam of not too large section. The distance between the battens is usually equal to the width of the insulation boards.
- After the mineral wool is installed between the bars of the frame, the vapor insulator itself is mounted. "Which side to install the vapor barrier?" - the question is actually very important. Its foil layer must be directed inside the room. It is with this arrangement that the effect of a thermos is created in the rooms and heat is best preserved. Most often, fastening is done on bars of a small section. Subsequently, a final finish is mounted on them. Sometimes the vapor barrier is also mounted on special brackets or slats (on both sides of the battens). In this case, the film is mounted close to the heat insulator. And the ventilation gap is obtained due to the difference in the width of the battens and the thickness of the insulator.
The vapor barrier tapes are mounted on the wall crate in a horizontal position with an overlap of about 15 cm. Sometimes additional gluing of the joint at the joint is done with adhesive tape.
Roof protection
Next, let's look at how to lay a vapor barrier in a subroofing space. Installation of the film in the attic or attic is performed in almost the same order as on the walls. The only thing, the insulation boards in this case are mounted directly between the rafters. Accordingly, the vapor barrier is attached to them as well. At the same time, bars, staples or slats can also be used.
Thus, we have figured out how the vapor barrier is installed on the roof. As you can see, the procedure is completely uncomplicated. It is necessary to use a vapor barrier when insulating the roof and installing a residential attic or attic.
Floor protection
Next, we will consider how to lay a vapor barrier on the ceiling. Carrying out the installation of the film on the floor, you should also follow certain rules. Mounting in this case is carried out in the following order:
- On the logs with fixation on the sides (for the device of the ventilation layer), a vapor barrier film is pulled. Fix it with staplers or small nails.
- Modern vapor barrier films are sufficiently durable, and therefore insulation plates can be laid directly on them.
- After installing mineral wool, another layer of vapor barrier is stretched over it from the attic or the next floor.
- The loft floor boards are crammed.
- Mounted ceiling boards in the lower room.
The ceiling is usually insulated after walls. The overlap of the material in the corners should be at least 20 cm.
Vapor barrier
Well, how to lay a vapor barrier on the ceiling, you already know. Now we will consider how to properly protect the floor insulation. This work is carried out in several stages:
- A layer of waterproofing film is laid between the lags .
- The heater itself is mounted.
- A vapor insulator is packed on top of the bars.
- Floor boards are mounted.
Rules for installing sheet material
Of course, it is also worth knowing how to lay a vapor barrier of this type. In this case, as in all others, the crate is initially installed. Sheets are mounted on it and fixed with screws. The joints are glued with tape.
Sizing rules
The answer to the question of how to properly install a vapor barrier is reduced to the following recommendations:
- The coating should be laid in a continuous layer, without leaving holes and preventing tears.
- It is advisable not to tighten the film during installation. Otherwise, it may just break. To avoid this, cut off the strip with a small margin.
- When insulating the walls or roof of a building from the outside, vapor barrier is installed first.
- After installing sheets or strips, it is necessary to check the strength of the fastening.
- Between the finish interior and the vapor barrier layer, a ventilation layer of at least 4 cm thick should be located.
It is important to know about which side to install the vapor barrier when using a membrane film. Mount it with the inner surface to the insulation. You can find out which side is the wrong side by marking.
Thus, as you can see, vapor barrier building structures with their own hands - the procedure is not particularly difficult. The most important thing is to do everything in accordance with the above recommendations. In this case, reliable protection of the insulation, as well as elements of the walls, floor, roof and ceiling will be provided.