Which side to lay the vapor barrier to the insulation on the ceiling, floor, walls and roof?

Thermal insulation will only be effective if this layer remains dry. This can provide a hydro and vapor barrier layer. As a result, the microclimate in the house will always be favorable.

The most widespread vapor barrier was obtained in wooden house construction, since the walls made of this material are most susceptible to the destructive effects of moisture.

Currently, you can find various vapor barrier materials. The choice is huge, and in order to decide and purchase the right material, you should familiarize yourself with their main types.

Which side to stack?

To prevent the formation of condensation, a vapor barrier is used, which is laid under the skin. Installation is carried out from the inside, on the side that faces the living area.

The vapor barrier film is fixed to the wall with a lathing. Thus, an air gap is created between the inner skin panel and the thermal insulation layer.

At the same time, the joints between the individual sheets of the film must be absolutely tight. This is ensured by the use of adhesive tape, which is glued to the joints.

In order to avoid the collection of condensation on the film, one of its sides is roughened. It is this rough side that must be turned during installation in the inner side of the room.

Many novice craftsmen do not understand which side of the vapor barrier film is laid. It has two sides, front and back. Most often they are the same, but if an anti-condensation film is used, then its fabric side should be on the side of the room.

If applicable foil membrane, then its foil side should face the heated room. In the case of purchasing a membrane film, you can determine the outer side by color, it is brighter and more saturated.

Scope and principle of operation

Thermal insulation, due to the fact that moisture acts on this layer, becomes useless and loses its properties.

Mineral wool heaters are exposed to negative factors both inside and outside the house. To protect housing from the cold, a high-quality vapor barrier is required.

The vapor barrier is designed to protect the building from the negative effects of weathering, precipitation, internal vapors and wind, and dampness.

There are certain standards according to which insulation should be protected.

For this, the vapor barrier material is placed between the thermal insulation layer from the inside of the house and the interior decoration. The work is carried out according to the instructions, since each vapor barrier material has its own characteristics.

There are two main types of materials - films and membranes:

1. Reinforced films. Used to decorate the attic, ventilation gaps must be created, since they do not allow steam to pass through.
2. Films with microscopic holes, are used to create a vapor barrier in unheated attics. They retain moisture well.
3. Anti-condensation film has an additional fleecy layer that allows you to retain water.
4. Membrane insulation with one or more layers - the material is durable and resistant to various influences.
5. Foil vapor barrier - has a metallized side, which must face the room.

The most commonly used polyethylene, which is widespread. But you need to work with it extremely carefully so as to prevent excessive tension and damage.

Membrane films have an unusual ability to pass air, while perfectly protecting against moisture. This is a new material that has a specific structure. It keeps the heat insulator dry for a long time. However, many membrane materials do not require an air gap.

What is the difference between vapor barrier and waterproofing?

Roof waterproofing scheme:

Roof vapor barrier scheme:

It is worth understanding what is the difference between these two types of insulation. The main difference is that the vapor permeability is significant significantly different.

Waterproofing materials are responsible for keeping warmth inside the room, preventing moisture from entering there. They protect surfaces from direct water ingress.

For example, when creating waterproofing roofs made of corrugated board, it allows water to be diverted outside the construction site. In this regard, waterproofing is installed using a special technology.

The vapor barrier faces a completely different task - protecting the thermal insulation layer from moisture and vapors entering it, which can destroy it. Steam is generated in most cases from the inside, which explains the packing of the material from the inside. For example, from the side of the attic or under the decorative finish of the sauna room.

Waterproofing materials do not allow water and moisture to pass through, while they can easily pass steam. The vapor barrier prevents this.

Varieties of vapor barrier

Insulation of floors

The floor and ceiling are essentially frame structures. Therefore, their vapor barrier is mandatory. The vapor barrier film is installed under the main floor covering and above the ceiling sheathing, creating an air gap.

Paul

Performed in rooms located on the first floor of the houseif there are basements below or basement floors, in baths and saunas. The material is laid from the inside after the creation of the waterproofing and heat-insulating layers. The material is fastened with double-sided tape or with the help of construction brackets, the canvases are overlapped.

Recommendation! The material is laid in two layers, from the inside and outside of the insulation.

Roofs

It is better to use a double-sided diffuse membrane here., the installation of which is carried out from the inside and outside of the roof. They are fixed to the thermal insulation layer without leaving gaps. If a roll-up hydro-vapor barrier is used, the edges when creating an overlap are also made out with tape.

Vapor barrier must be created in any case if tiles or metal profiles are used as roofing material.

Sten

Distinguish between internal and external. The material is fixed around the perimeter with a stapler, the docking is made with an overlap of approximately 10-15 centimeters, and the joint itself is glued with tape. From above it is necessary to hammer in wooden slats, which are a crate of thermal insulation.

The frame for thermal insulation can be made of metal profiles or wooden slats, a vapor barrier is created, which is attached to the wall using self-tapping screws.

On which side of the heat insulator to mount?

1. The vapor barrier is installed, as a rule, from the inside of the thermal insulation. But most often a two-sided composition is created, which allows you to provide a reliable barrier between the outside of the building and the room.
2. When insulating the facade, the film is laid on the outside of the heat insulator. At roof insulation, the film is fixed on top of the mineral wool, as in ventilated facade. When creating a cold roof, the vapor barrier is placed under the rafters.
3. When insulating the top covering, when an attic space is created, the barrier is placed underneath the heat-insulating material. With internal wall insulation, the film is fixed over the heat insulator, inside the heated room.

Recommendations

1. Surfaces before vapor barrier must be properly prepared.
2. If the work is carried out in the cold season, the mastic is diluted with antifreeze.
3. The ventilation gap is at least 6 centimeters wide to provide protection against condensation. The wall cladding must not come into contact with the film.
4. When insulating the roof, the creation of a gap is provided by a crate, which is mounted from racks or horizontal profiles.
5. The joints of the vapor barrier canvases must be glued. This is done using self-adhesive tapes. Scotch tape, especially narrow tape, is not recommended for this work.
6. Installation can be done with a stapler or wide head nails. But experienced builders recommend using counterrails for these purposes.