Attic ventilation in a private house: rules and devices for organizing air exchange

Alexey Dedyulin
Checked by a specialist: Alexey Dedyulin
Author: Alesia Markova
Last update: December 2019

Regular air exchange within the attic space and in the roofing system is necessary for the long-term service of the roof and the building as a whole. Properly organized attic ventilation in a private house provides thermal control of the room. It will prevent the formation of mold, dampness.

In the article, we will consider why a perfectly functioning air exchange in the attic space is needed. We will talk about which ventilation systems are required for the complete removal of moisture and condensate. We’ll introduce you to the principles of operation of the ventilation system and its device options.

When doing the work yourself, use the diagrams, ventilation calculations, as well as useful photos and videos with tips for arranging ventilation systems.

What are the functions of ventilation?

The process of air exchange in the room is to regulate heat transfer processes and maintain optimal environmental performance - temperature, humidity level, speed of movement of air masses.

An engineering system equipped in accordance with the established technical requirements ensures the free flow of air, its movement in space due to installed dormer windows, vents, aeration devices of various designs and other openings.

Ventilation system with recuperator in the attic
A device of normally functioning ventilation is especially necessary if equipment of the supply and exhaust ventilation system or duct air conditioner is located within the non-residential space. If condensate settling on it is not removed in a timely manner, it will be necessary to repair it very often

The functional purpose of the system is the regular supply of the required amount of air and its subsequent removal, which contributes to:

  • moisture reduction in the room;
  • providing the necessary microclimate;
  • preventing the formation of condensation and the development of fungus;
  • creating continuous air exchange;
  • Prevention of deformation of rafters in the building.

Ventilation should be carried out both in a warm and in an uninsulated attic. In summer, the roof surface heats up to high temperatures, transferring most of the heat to the lower part of the house.

Installation of spotlights along the eaves
In the presence of ventilation devices, a decrease in temperature indicators occurs inside the entire building, which reduces the load on the air conditioning system, if any

High humidity in autumn-winter period affects the microclimate of the attic. At the same time, the thermal insulation qualities of the structure will be significantly reduced, because the water contained in the insulation and materials will contribute to heat loss. Therefore, an air exchange system is equipped to remove excess moisture.

Due to the large temperature difference inside and outside the room, condensation forms, the walls, floor, floor beams, rafters, rafters, Mauerlat, vertical racks get wet. All this leads to rotting of the wooden components of the roof, the appearance of dampness.

Condensation on the inside of the roof
Due to the difference between the temperature outside the roof and in the attic space, condensation forms on the inner surface of the roof or in the insulation. It must be removed by ventilation.

For effective ventilation of the room throughout the year, without heat loss in the house, the following technical standards are provided: for every 500 m2 premises need 1 m2 vents.

In addition, in order to prevent the formation of water droplets on the beams of the structure, it is necessary to carry out insulation measures - lay steam- and hydroprotection.

The nuances of the equipment of the air exchange system

In organizing roof ventilation, one or more organization methods are used. Air exchange directly depends on the characteristics of the attic space, its area, shape, type of roof and building materials used.

Roof Turbine Aerator
When installing the system, it is necessary to take into account the amount of precipitation characteristic of the region. If there is a risk of snow falling on the ridge and hip ridges, it is better to supplement conventional vents with turbine aerators exceeding the height of snow drifts

The specificity of the roof ventilation device is that you need to provide two directions indirectly connected with each other, these are:

  • Ventilation of a roofing pie. It is needed to dry the system under the roof covering: insulation laid on the slopes, rafters, crates. It is provided with vents and aerators.
  • Removing excess moisture from the attic. It is required to drain the attic or attic, the formation of a microclimate in it, favorable for extending the service life of the structure and the stay of the owners. Provided by ventilated gable windows, holes, hatches.

The roofing cake is ventilated with products - longitudinal channels laid from the eaves overhang to the ridge ridge. The vents are formed during the laying of the crate and the counter-crate on the rafter legs.

Scheme of air movement through roofing products
In the ventilation channels formed by the crate - the air ducts - the air moves from bottom to top. It is tightened in the area of ​​the eaves and displayed outside in the ridge zone from the side or from the top

The distance created by this method allows air to enter the area of ​​the cornice and exit in the area of ​​the ridge, taking with it condensation and moisture settled under the roof.

For the roof of ondulin, bitumen, polymer-sand and natural tiles additionally use aerators, repeating the shape of the roofing material. If they do not differ in color, then literally merge with the roof. The integrated grill in them allows air to move freely in the direction necessary for drying.

Tile roof aerator
Aerators for tiled roofs can practically “merge” with the coating.They are used mainly on hip, semi-hip and tent roofs, in which the ridge rib is shortened or not at all.

In the case of the roof of the roof with corrugated steel, metal and corrugated board, with the installation of the ventilation system of the roofing pie, it is somewhat complicated. The installation of the crate should be performed with gaps, i.e. with additional transverse channels.

If the gap in the crate was not initially observed, then in the gratings under the profiled steel roof, side holes are drilled. They are located after about 30 cm. As a result, the area of ​​the drying air heater dehumidifies due to the movement of air not only upwards, but also sideways.

Lathing device with a gap
Lathing with a gap in laying or with drilled transverse holes increases the area covered by the air flow. So the insulation of the roofing cake is washed by air currents, moving both along the ramps and across

Air exchange in houses with a flat roof is characterized by the absence of gables in which attic windows can be installed. And although there is still an attic in competently arranged flat and low-sloping roofs, they are ventilated through the ventilation openings.

Flat Roof Pie Ventilation
The flat roof roofing cake is ventilated by a system of aerators, the installation step of which depends on the thickness of the insulation and the area to be treated

The space in large hip roofs is ventilated through dormer ventilation windows, in small ones through ventilation vents.

Despite the fact that the inclined ribs of the hips are arranged according to the ridge principle, they cannot provide a sufficient outflow. To remove and eliminate possible stress, put aerators.

Hip roof dormer
For ventilation of attic spaces and mansard rooms of hip and tent roofs, dormer windows are arranged. They can be with flaps or with a stationary grille

Air exchange in the attic space of a gable roof is often organized by arranging ventilation openings with gratings, as well as through ventilation or dormer windows. For natural circulation of air flow, both openings and window openings should be located on both sides.

Features of the organization of the ventilation system

For the proper functioning of the system, the following recommendations should be observed:

  1. For the free flow of air under the roof, it is necessary to leave special holes, gaps.
  2. Organize an air exchange system so that air masses enter from the bottom of the roofing cake and exit through the remote clearance in the ridge ridge.
  3. Place a sufficient number of ventilated devices, openings, taking into account the area of ​​the room to ensure free movement of air in the attic.
  4. Ventilation ducts must be equipped with valves to be able to control the intensity of ventilation, as well as mosquito nets to prevent insects.

Holes in the skates, under the roof overhang, provide circulation due to the force of the wind and the thermal movement of the masses circulating in the atmosphere in a natural way.

Products: location rules, calculations

In a properly arranged roofing cake, the air movement is directed from below through the vents, and then up to the skates with holes. Along the line of the ridge, a gap of 3-5 cm is necessarily left, which is covered with a ridge plate on top, next to the ridge tile, two paired boards and similar devices.

If the ridge is hermetically closed, which prevents the air from escaping, then ventilation holes are made just below the ridge run in the pediment. They do not cancel the need to arrange pediment and auditory window openings, because different ventilation tasks are being solved.

Scheme of the insulated roof
Products are formed by installing crates and counter-crates on the rafters.They at the same time form the distance between the insulation and vapor barrier from the inside, insulation and waterproofing outside the roofing pie

Regardless of the type of roofing, almost all roofing pies are supplied with products. They are satisfied both in the insulated roofs of attics, and in cold constructions without thermal insulation.

From below, along the eaves overhang, the whole pie, together with these ventilation ducts, is covered with a mosquito net, which at the same time protects from dust.

Using aeration and mosquito nets
The air in the roofing cake is covered with a mosquito and aeration net. They freely pass air, but retain insects, small birds, foliage, fragments of branches, dust

In addition to the products laid in the roofing cake, there are also holes located in the upper part of the wall, along its line with the ramp.

Wall products dividing into the following types:

  • slotted, about 20 mm wide - are located on both sides of the cornices, forming a gap between the wall and the roof;
  • point, with a diameter of not more than 25 mm - look like holes on the surface, the size of which depends on the slope of the slopes.

The specified size of fixtures is important to observe when arranging ventilation system. If there are holes of a smaller or larger size, the efficiency of the circulation of air flows will be reduced.

Wall ventilation for attic ventilation
If for ventilating the attic it is impossible to make holes in the gables and put up dormers, wall ventilation ducts are arranged in the walls under the roofing system

The width and number of holes may vary depending on the dimensions of the roof. For regular and proper ventilation without excessive heat leakage from the room, the total area of ​​vents in the attic should be 0.2% of 100% of the area of ​​the room. Also, one should not forget about the correctness of their location.

An example of the calculation of vents when installing in a roofing cake:

  • for a 5-meter roof, the holes should be 8 mm;
  • 6-meter - the width of the holes is not more than 10 mm;
  • with a roof width of 7 to 8.5 m, the ventilation should be 12-14 mm;
  • the roof with a width of 9-10 m is equipped with 16 mm ventilation openings.

If the products are located in the lower part and on the ridge, their width should be reduced by half. It is not recommended to exceed the allowable area of ​​the holes, since precipitation can get into them.

Air outlet in the area of ​​the ridge rib
Roof slopes do not connect closely, leaving a gap along the ridge ridge. It is covered with a ridge aerator, a set of tiles or a ridge plank

Outlets in the upper part of the roof are designed for retracted flow output. Their area should be 15% more from the supply air. For this, aerators or special grilles are used - more innovative devices that provide the required temperature difference and pressure level during air movement.

Rules for installing attic windows

When equipping the attic with auditory or ventilation windows, you will still need to additionally prepare air vents and vents. This option is considered highly effective, since moisture not removed from the roofing cake will prevent full ventilation of the premises.

To improve circulation and reduce air stagnation, the dimensions of the ventilation devices of the attic ventilation in a private house should be 600 × 800 mm.

Ventilation windows on the gables
The fronts of low-pitched roofs do not allow to arrange a full-fledged window in them. In houses with gable roofs, ventilation windows with a stationary or opening grill are arranged.

Steps for installing attic windows:

  1. Wooden frames are attached to the rafters using racks.
  2. Next, lay the roofing.
  3. The openings are finished with lining or other material.
  4. After that, the window box is mounted in the prepared opening.
  5. Having fixed the frame, it is necessary to eliminate all the cracks between the roof and the window using mounting foam.
  6. Last but not least, a double-glazed window should be inserted.

The installation of attic windows can be done independently according to the instructions or use the services of specialists.

When installing the window, you must adhere to some recommendations:

  • should not be placed close to the ridge;
  • in addition they can be equipped with a grill;
  • interwindow gaps should not exceed 1 m;
  • It is necessary to position the device in this way: the lower border of the window should not be lower than 1 m from the level of overlap, the upper - not more than 1.9 m

Their design can be varied. Mostly builders select the form of ventilation devices depending on the type of construction and architectural concept.

Engineering System Tips

To determine the level of complexity of work during the installation of the system, we consider the ventilation features of the insulated residential and non-equipped cold attic space. We will figure out what are the differences in the organization of air exchange with a different type of room insulation and temperature conditions.

Attic ventilation arrangement
Attic ventilation devices perform the function of thermoregulating the entire building. With proper installation, ventilation and attic windows will reduce heating costs, provide the necessary level of cooling in the summer

Air exchange prolongs the life of the roof, roof frame, equipped and not equipped rooms under the ramps. The system also prevents the accumulation of snow, icing of the roof, the formation of moisture.

Non-residential attic ventilation

A cold loft not equipped for living is a space under the roof without insulation and finished walls, floors, which serves as a technical floor. However, it also needs to be equipped with a ventilation system.

It is optimal to deal with this issue at the stage of project development and construction. To circulate air currents, the rafters and grilles should be partially open.

To organize the movement of air, use various devices. For the influx - spotlights with small holes, which cover the overhangs from the bottom up to the wall of the house. The special design prevents debris and insects from entering the room, but allows air masses to flow freely.

Pitched roof overhangs
If it is not possible to equip the eaves overhangs with soffits, they are sewn up with corrugated board with perforated elements or a regular board, leaving ventilation gaps between the elements

The panels are available in several versions. The most common types of products:

  • solid - used for installation on gazebos, porches, terraces;
  • perforated in the center - placed on the fronts, eaves overhangs of roofs;
  • fully perforated - designed for roofs covered with bituminous tiles.

When covering the roof with slate, ondulinWithout the use of insulation materials, natural air exchange will occur. Therefore, in the attic you do not need to organize a special ventilation system.

Open corrugations of a metal tile
The butt of the metal and tile roofs, corrugated board, ondulin do not close along the cornice. In the area of ​​the ridge, before installing the coating, a porous polymer tape is installed that freely passes air streams

Gable roofs are most often equipped ventilation ductsthat place in the fronts. If there are small gaps on the overhangs, air circulation will occur correctly.

If the stitching fits snugly over the eaves, you will need to make a few holes, according to the standards for organizing ventilation, or install special grilles with grids with a pitch of 80 cm along the entire overhang.

Air flow pattern in the attic
Ventilation of the pitched roof attic space is provided by windows or openings arranged in the gable or tongs of the gable structure. If they are equipped with glazed sashes, volley ventilation should be carried out periodically.

When arranging an air exchange system, it is necessary to take into account design features and shape. For a certain type of roof, a variety of ventilation elements are used.

For the efficient operation of the engineering system, devices are necessary not only for the inflow, but also the elements that will discharge the exhaust air masses. In practice, various options are used - deflectors, make the skate ventilated, leave a gap around the perimeter of the roof, others.

Warm attic: do I need air exchange?

The attic is an integral part of the house, which can be used as an additional area for permanent residence. However, this will require not only to insulate it, but also to properly organize the ventilation system.

For the attic, they design and arrange everything as they usually do in an organization ventilation of a two-story house. You should carefully consider the design and select the necessary elements of air exchange, taking into account the area of ​​the attic.

Ventilation options for the equipped attic at home
The space of the equipped attic is ventilated as a normal room. For ventilation open windows. If they can’t cope, the supply and exhaust valves with fans are mounted in the ramps

Consider the basic ventilation equipment schemes for various types of roofs:

  1. From sheet material, flexible tiles - equip the ventilated zone by stripping strips on a continuous crate of plywood or OSB boards.
  2. Of metal tiles - It is recommended to use a rafter crate.
  3. From slate ondulin - for free entry and exit of air is not required counter grill. The material is attached to the crate, which will form a distance for the free entry of air flow at the eaves and exit through the ridge.

In modern homes, aerators are installed to remove exhaust air. Devices prevent the occurrence of condensation, and also prevent the penetration of precipitation into the room.

The living area should be ventilated no worse than other rooms. Air masses enter through attic windows and additional valves, and exit through the upper ventilation devices.

For the correct ventilation of the residential attic floor, use the following scheme:

  • place pipes with a deflector on the roof;
  • ventilation grates are installed in the gables;
  • in the upper part of the roof or the outer wall heat insulated ventilation duct.

To install air exchange elements on the roof, only durable products that are resistant to wind gusts and precipitation should be used.

Conclusions and useful video on the topic

Popular ventilation methods for condensate removal:

Organization of ventilation of the room by making ventilation holes in the pediment:

Tips for arranging an air exchange system within the attic under a cold roof:

Arrangement of attic ventilation in a private house is a mandatory procedure. It is important to pre-perform calculations on the number of required openings and devices for air circulation. Since the microclimate in the premises deteriorates at low efficiency of the system, there is a risk of destruction of the roof structures and the life of the building is reduced.

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