Ventilation cold lofts

The attic is a non-residential space located above the top floor of the house, directly below its roof. According to a long-established tradition, the attic of most buildings is practically not insulated, but now the gaps in them are carefully sealed. Therefore, the system of rafters, placed in the under-roof space, is completely unprotected from climatic influences.

For many of us, the situation with well-ventilated attics is familiar from the historical fact that in the old days they were used to store unwanted household items or things that had served their time.

From a purely technical and functional point of view, the ventilation of cold lofts has the following goals:

• removal of vapors generated in residential areas;
• protection of truss elements and insulation from the damaging effects of moisture and fungus;
• regulation of the temperature regime of the attic.

It is for this reason that the rafters and lathing in such a room are made completely open, that is, they are not sheathed with any protective material. This technique ensures the creation of conditions conducive to their constant ventilation. As an alternative, trimming of wood structures with a cut board with small gaps, providing free air access, can be considered.

Note! In cases where slate or ondulin is used as a roof covering (without vapor and water insulation), the question of the organization of ventilation disappears by itself. This can be explained by the fact that moving air masses freely penetrate into the slots, always located between the individual sheets of roofing material. Natural ventilation of attic spaces under metal roofing roofs is carried out in the same way (except for cases when film vapor barrier is used for their installation).

Variants of the organization of airing attic

In conventional gable roofs, narrow slots can be used as elements of natural ventilation, deliberately left when cladding attic gables. In cases where the latter are laid out of brick or there were no gaps in them, you will have to make small holes of square or round shape (see the figure below).

Note! In order to avoid the formation of stagnant zones under the roof, it is recommended to prepare several holes, taking into account that their total area does not exceed 0.2% of the area of ​​both gables.

As a protective fence for such openings, it is easiest to use standard ventilation grilles with cells facing downwards (to prevent rainwater from leaking into them). In addition, it makes sense to build in them special mosquito nets that protect the attic from insects.

For the hip version of the roof structure, the system of inlet vent holes is settled, as a rule, in the wind sheeting of the roof. At the same time, special slots located closer to its ridge are provided for the outflow of air flow on the roof. In this case, wind binder boards are not pinned very tightly, forming small gaps of about 3 × 4 millimeters.

Note! When making plating of plastic materials in the sheets along the entire length are drilled small holes? the so-called perforation.

As for the holes used for the withdrawal of air flow, they usually settle in the upper part of the roof; And the place of their exact location is selected as follows:

• as a rule, the ridge is used as a zone for air masses for the roof of shingles;
• the set of ceramic coatings for these purposes provides a special roof valve;
• in slate or ondulin coatings, an outlet vent is made directly in the ridge;
• for metal tiles, the air outlet is arranged in the ridge seal (sometimes the same roof gates are used for this).

In the final part of this chapter, I would like to note that for independent production of round or square shaped ventilation holes you will need to prepare the following tool:

• hacksaw, hammer and chisel (for processing wooden gables);
• electric or hand drill, jigsaw;
• classic hammer drill (to prepare holes in masonry).

Also note that you will have to pay a decent amount for the roof gates mentioned above, while using ridge gaps will be much cheaper, and it will be much easier to do this.

There is another way to arrange the natural ventilation of cold attics, involving the use of dormer windows decorated with openwork grilles. Of course, that this option of airing the roofing space will require you to spend considerable time and money.

Creating the required microclimate

The need for ventilation of attic rooms is primarily due to the need to create a certain microclimate within the spaces they occupy. This means that if the roof heats up in the summer, it is necessary to ensure that the heat does not penetrate from the attic into the residential floors below.

The simplest way to solve such a problem is the ventilation considered above, with simultaneous cooling of stagnant air masses. On frosty winter days, the flow of cold air into the roof space, on the contrary, may be limited.

Note! The natural ventilation system of the attic should have a mechanism to block the inflow and outflow of air, that is, to be adjustable with the help of special dampers.

Video

This video describes how to make ventilation in a cold attic: