Required condition In order for the roof to serve reliably and for a long enough time, it is equipped with the correct ventilation system, which will ensure ventilation of the under-roof space. Ventilation can increase the service life of not only the building itself, but also the entire building. An improperly executed ventilated system can lead to a lot of negative consequences, and effective ventilation will prevent mold and premature deterioration of the material.
This article describes in detail the most important points regarding the installation and operation of the ventilation system:
- Roof service life
- Lack of roof ventilation: negative consequences
- Benefits of having a ventilation system
- Ventilation system
- Ventilation installation options
- Roof cornice: types and protection options
Roof service life
A completely natural process is the accumulation of warm air under the roof of a house, formed during washing and drying clothes, cooking and washing dishes. In summer, on the contrary, hot air penetrates into the room.
For mansard type roofs are the only thing the right way counteracting the above phenomena is the creation correct system ventilation.
A proper ventilation system should be understood as the presence of ventilation outlets on the roof from hoods and other systems, as well as ventilation of the space located under the roof. Compliance with all these conditions guarantees a longer service life of both the roof and the entire house.
Lack of roof ventilation: negative consequences
If the ventilation system is not properly installed, condensation will wet every element. And getting wooden roof structures wet can lead to very dangerous consequences.
Negative consequences improper roof ventilation:
- Formation of mold and mildew on load-bearing elements of the roof structure;
- Destruction metal structures corrosion, as well as destruction of concrete parts;
- The layer of ice that forms on the roof allows moisture to penetrate under the roof covering, resulting in damage to the roof and drainage system;
- Reduction in the thermal properties of the material due to moistening of the thermal insulation layer;
- Significant heating of the air inside the building in summer period due to the strong heating of the roof covering.
This is especially negative when the attic is a living space, and roof covering made of bitumen shingles.
Increased costs aimed at improving the air conditioning system inside the house.
Benefits of having a ventilation system
The main function that a ventilation system should perform is to ensure the passage atmospheric pressure, which helps to draw out heated air from under the roofing.
The extracted air ensures ventilation of the attic space. If installation ventilation system performed correctly, then such an air flow occurs naturally, and there is no need to additionally use mechanical equipment.
Thus, the presence of a ventilated space under the roof has the following advantages:
- Always keep the attic space dry and cool;
- External air from the attic is able to escape naturally;
- The load-bearing elements of the roof, coating and thermal insulation layer are not affected by high humidity;
- No environment for the formation of rot and mold, preventing damage finishing materials coatings;
- Saving energy costs.
Ventilation system, roof ventilation
It is advisable to install a ventilation system on any roof.
To do this, you must apply the following elements and actions:
- installation of ridge or cornice vents and;
- laying a roof covering with tiles with holes for ventilation;
- ventilation skates;
- installation of the roof with gaps for ventilation;
- arrangement of a dormer window or a continuous ventilation channel along the valley (gutter);
- installation of additional elements, in particular if available chimney, ventilation shaft, which involve ventilation passing through the roof.
Ventilation installation options
Let's look at the most common methods of installing ventilation.
Roof aerators (point exhaust ducts) are installed near the roof ridge or on it. Continuous exhaust outlets can also be installed, and both can be combined with common system Houses.
The most effective ventilation system is one where the outlets are installed along the entire length of the roof fin. The presence of exhaust outlets does not spoil appearance neither a roof nor a building, since they are usually covered with the main covering from above.
When installing ventilation of this type, you should remember some points that may reduce air inlet and outlet:
- Usage polyurethane foam or tape for sealing the ridge strip disrupts the natural ventilation of the roof.
- Roof structure made with two ventilation gaps. The film located under the roof completely prevents air flow. The solution to this problem is cutting through the roofing film.
Please note that for absolutely all roofing coverings, standard elements are produced, which are aimed at ensuring effective ventilation.
These elements include:
- Tiles equipped with air channels;
- Aeroelements;
- Ventilation rolls.
All these elements provide ventilation of the under-roof space. But a more effective system will be one that has a fully ventilated ridge, that is, ventilation through the roof. Use only individual elements provide insufficient high-quality ventilation.
Roof cornice: types and protection options
Architects and designers usually do not like the various ventilation grilles and strips that are located on the eaves overhang. But it is precisely such details that provide sufficient area of entrances, allowing air penetration and creating excellent ventilation of the roof.
There are the following types of cornice ventilation:
- The gap left between cornice board and the wall of the house;
- Cutting plastic ventilation grilles into soffits;
- Laying special material with vents slightly above the overhang of the cornice.
When laying insulation in the eaves, the ventilation vents will be closed. The passage of air masses is also obstructed by green carpets of plantings located on the eaves. This should always be remembered so as not to disturb the ventilation system of the building.
Methods for protecting roof eaves ventilation ducts:
- Overhang aero elements or grille;
- installation of devices on the roof to retain snow;
- drainage system, which is located under the roofing.
The most difficult part of the roof to ensure reliable ventilation is the valley.
When arranging a roof with a short eaves overhang, long valleys, as well as two gaps for ventilation, ventilation difficulties may arise, since almost all the places where the slopes and valleys adjoin are completely deprived of the possibility of ventilation.
To avoid such difficulties, it is necessary to make openings in the film in the rafter spans to provide air flow, or to equip a continuous ventilation channel along the groove.
Important! To avoid disruption of ventilation, aeration elements can also be installed along the valley. True, these measures will be effective only for roofs with a slope angle greater than 45 degrees.
This type ventilation systems are ineffective for flat roofs. It would be preferable for this type of roof to install roofing electric fans, high ventilation nozzles or inertia turbines.
It should also be noted that every additional element ventilation system increases the overall cost of arranging the roofing. Therefore, the cheapest option is natural ventilation of the under-roof space.
The most common type of ventilation system is a dormer window (hole), which can provide not only high-quality ventilation attic space, but also the aesthetic appearance of the roof.
It is customary to distinguish between the following types of auditory openings:
- triangular;
- semicircular;
- trapezoidal;
- rectangular;
- single-pitched;
- gable.
Single-pitch ventilation openings are suitable for any type of roofing. Gable openings are suitable for metal and soft roofs. Complex ventilation windows more efficient and durable.
In conclusion, it should be noted once again that reliability and long service Roofs are affected not only by the design of the rafters and roof covering, but also by the ventilation of the space under the roof.
Even a minor mistake in the roofing design can cause premature failure of the roof and building.
Despite the hype around some roofing materials, the comfort and warmth in the house is influenced not so much by them as by competent installation of the roof. If the construction was carried out professionally, observing existing standards, then any covering will be a reliable barrier to the surprises of nature, be it cheap slate or expensive metal tiles, and the entire roofing structure will save heat in the house and eliminate excess moisture. But the presence of condensation and high humidity “hints” that not everything is going smoothly with your roof. Well, to be more specific: during installation, the roof ventilation was created incorrectly (if it was created at all!).
And there are several reasons: either the roof was laid by non-professionals, or vapor barrier or waterproofing films were applied incorrectly, or the ventilation system was created without taking into account the type of roofing. There is only one result: you will have to disassemble the roofing pie and reinstall it.
What layers should a roof ventilation system be made of?
Roof ventilation consists of three components, each with its own function:
- Ventilation between the roofing and the waterproofing layer. Its task is to remove condensation from the roof that forms on the back side of the covering.
- Ventilation between waterproofing and insulation. It is needed so that moisture that has entered the insulation from the air has the opportunity to leave the roof. If this layer is not created, the insulation can absorb water as a result of roof leaks or during the rainy season and cease to function as a heat insulator.
- Ventilation of the internal under-roof space. This layer is responsible for removing vapors from the premises and does not allow them to settle as condensation on inside roofs.
In this roof, the ventilation of the under-roof space is not thought out, so there is a lot of condensation on the roof
What laws of physics should be taken into account when installing ventilation?
Steam and water will seep into the roofing pie from both sides. The ventilation system should either prevent this from happening, or, if it gets in, allow the moisture to evaporate. It should be remembered: the steam does not flow perpendicularly upward, but slightly deviating to the side. The water does not go perpendicularly down, but also deviates slightly.
This deviation is not always taken into account when forming a roofing pie, and the following installation errors are made:
Ventilation of the under-roof space. Errors in ventilation installation will lead to destruction of the roof structure
Mistakes in using vapor barrier and waterproofing films
Even when created in roofing pie all necessary air gaps, ventilation will not be able to ventilate all the moisture if waterproofing or vapor barrier films were installed incorrectly. They are often confused due to their external similarity. But these films have different tasks, and, accordingly, a completely different structure.
Let's consider what problems will fall on the head of the owner who has mixed up the purpose insulating materials:
- If you laid a vapor barrier film instead of a waterproofing film. The vapor barrier film completely eliminates the ingress of moisture from both sides. If you lay it on top of the insulation, then the moisture that gets from the air into the heat-insulating material (and it will definitely get in, especially during seasons of high humidity!) will remain in it, because it will not find a way out. As a result, every year the insulation will become more and more moistened until it finally loses its properties completely, and the owners will be faced with high heat losses.
- If you laid a waterproofing film instead of a vapor barrier. Waterproofing films (also called diffusion membranes) have special properties: one side “breathes”, and the other is waterproof. They are laid under the roofing, turning the breathable side towards the heat-insulating layer. In this case, there should be a ventilation vent between the layers. Then the moisture from the insulation will partially escape through the air gap, and the rest will seep through the funnel-shaped holes of the film under the roof and evaporate. If water accidentally gets through the roofing (as a result of leaks, through cracks, etc.), it will settle on the film and will not be able to penetrate deeper. And in the same way as moisture from the insulation, it will go home.
If secured correctly waterproofing material on a skate, then the steam will not find a way out
When installing a waterproofing film, it is the other way around, i.e. on the “breathing side” of the insulation, water and moisture entering from the outside will easily enter the insulation through the funnels, and will no longer be able to get out. As a result, the entire design of the roofing pie loses its meaning.
Another option is when instead vapor barrier film lay waterproofing. If you place it with funnels inside the house, then all the steam will instantly seep into the insulation, if on the contrary, then the moisture from the insulation will return back into the under-roof space, although not much.
Errors in a ventilation system created without taking into account roofing material
Some owners, out of ignorance, create not as many ventilation layers in the pie as a certain roofing requires. For example, metal tiles and euro slate are afraid of condensation on the back side, so a ventilation gap must be provided between them and the waterproofing layer. Those. They fill not a solid sheathing, but a lumber one, leaving gaps for air to circulate. If water gets under the roof from the outside, then with the help of this layer of ventilation it will be able to evaporate through the ridge.
The grille paired with the counter-lattice will create an air gap sufficient for condensation to find its way out
At the same time, anti-condensation films are used as waterproofing, which do not release vapors from the insulation under the roof, thereby relieving the roof covering from additional condensate. But here is the second point: where will the moisture go from the heat-insulating material if it is not released under the roof? To do this, create a second layer of ventilation, leaving an air “cushion” between the insulation and the anti-condensation film.
You cannot lay diffusion and superdiffusion membranes as waterproofing, because they are designed to allow steam to pass under the roof, and in such roofs this can lead to corrosion of the metal tiles.
Only a properly created ventilated roof will retain heat and remove excess moisture from the house.
In the roof pie, the waterproofing material is surrounded by a double ventilation gap
Soft tile roofs
And these roofs are not afraid of condensation, so they do not require a serious air gap between the coating and the waterproofing. A continuous sheathing of plywood, boards, etc. is installed under them. Wooden materials themselves allow air to pass through well, so natural ventilation will work in any case.
Creating an air gap between the waterproofing and insulation will depend on which film you choose:
- Anti-condensation films are not installed on soft roofs. Diffusion membranes are used here. But to prevent the funnels from becoming clogged with insulation particles, an air gap must be left.
- If you plan to lay a superdiffusion membrane, then it does not need an air gap. The level of moisture passage is high and allows you to do without a ventilation layer. Such a membrane is laid directly on the heat-insulating material.
In this cake, the waterproofing layer is created using a superdiffusion membrane. It does not require a ventilation gap, but lies directly on the insulation
Having created all the necessary ventilation gaps, it should be remembered that steam will tend upward and water downward only when there is air movement. Don’t forget to make a ventilated underlayment and install aerators on the upper edge of the roof or on the ridge. Otherwise, the roof will not be properly ventilated.
Moisture can enter the house from the outside in the form of precipitation and from the inside as condensation. Its presence in the premises leads to the spread of harmful microorganisms and mold, which will be difficult to cope with. Prevent this and increase the lifespan of your home with warm attic A roof ventilation system will help.
Purpose of forced ventilation of the roof of a house
When arranging the roofing pie of a household with a residential attic, experts observe the principle of complete tightness, arranging the materials in layers, overlapping each other. Thanks to the design of such a system, it is created reliable protection from moisture and heat remains indoors.
At the same time, the “pie” is an obstacle to exhaust through the roof. That’s why they make a forced ventilation system in a residential building, which is installed in accordance with the requirements specified in SNiP.
This design solves a number of problems:
- It releases warm air saturated with water vapor into the atmosphere, which collects in rooms located on the lower floors. If there is no effective exhaust, steam begins to settle on the elements of the rafter system in the form of condensate.
- Prevents excessive dampness and unpleasant odors from appearing inside attic room. The roof ventilation system creates an influx of air from the surrounding atmosphere, which helps create a favorable microclimate in the house.
- In hot weather, it lowers the heating temperature of the roofing surface. Proper ventilation can minimize this.
- Provides protection of the roof surface from ice accumulation. Due to the difference between the temperature outside and inside warm home The snow mass begins to melt. As a result, ice constantly forms, which is not easy to deal with.
- The original qualities of the thermal insulation material are preserved. An increase in the humidity level of insulation by 5-10% due to the formation of condensation leads to an increase in its thermal conductivity by 35-50%. Even if it dries completely, this indicator does not return to its original value.
- In accordance with the provisions of SNiP, an attic can be called suitable for living if it has a forced ventilation system. In this case, the total area of the ventilation vents must be at least 1/300 of the roof surface.
Roof ventilation elements
Functioning forced ventilation according to the principle of convection: since warm air is lighter, its currents move upward, while making room for cooler air masses with greater weight. Often it is also installed to facilitate air circulation.
According to the provisions of SNiP, in order to ensure exhaust, the following elements of roof ventilation will be required:
- Cornice vents. Through them, one penetrates under the roof with an attic atmospheric air. To make vents, inexpensive lumber is used, which is attached with a small gap, or special structures - soffits, which are metal or plastic panels with partially applied perforation. Due to these holes, air freely penetrates into the room.
- Dormer windows. They serve to extract and provide access to air. Such windows are installed if the attic space in the house is not heated and is not used for living.
- Ridge aerators. This ventilation element, which has perforation, is mounted along the ridge of the attic pitched roof. It serves to remove heated air from the room outside.
- Pitched deflectors. These devices are nothing more than pipes for ventilation. These air ducts are installed on the roof, on the slopes. They consist of a tube with a cross-section of 20–50 millimeters, which is laid through layers of insulating pie. The deflectors are equipped with a protective mesh and cap on top.
- Modular roofing material. Lay a covering of individual tiles, leaving gaps for circulation air masses. From the point of view of ventilation arrangement this material is more a good decision for roofs with a warm attic than sheet steel or soft bitumen shingles.
Roof ventilation elements for a heated attic and a cold attic are significantly different. For non-residential premises two dormer windows and eaves vents will be enough.
If designed residential attic, then installation of more complex system, consisting of:
- pitched deflectors;
- cornice vents;
- ridge aerator.
According to SNiP, the number of ventilation holes is determined taking into account the area of the roofing surface at the rate of 1 - 2 pieces per 25 “squares”.
Pitched deflectors and air ducts for roofing
These devices are placed on roof slopes to remove heated air from the attic space and moisture from the layers of the roofing pie.
Deflectors consist of the following elements:
- Frame. In appearance, it resembles a bottle, which has two parts. Its lower part is placed in an insulating pie at the arrangement stage, and the upper part is installed at the end of the work. The diameter of the case can be 30–50 millimeters.
- Protective filter. It is installed inside the deflector housing. A mesh or sponge filter is required to protect the ventilation structure from debris.
- Umbrella or mushroom. This part is placed on the head of the housing pipe so that moisture does not penetrate into it during rain or snow.
- Flange. To ensure the tightness of the junction of the deflector with the roof pie, an apron made of silicone or rubber is used.
Install air ducts on the roof at a distance of 50 centimeters from the ridge - like this warm air It will be easier to go outside. Even on roofs whose area does not exceed 25 square meters, you will need to install 2 deflectors.
Rules for installing ventilation system elements
In order for the ventilation installed on the roof of the house to function efficiently, ensuring the circulation of air masses inside the attic room, you must adhere to several simple rules:
- The height of the ventilation pipes above the roof of the building should be 50 centimeters.
- When the pipe is installed at a distance of 50-150 centimeters from the ridge, it needs to rise above it by 50 centimeters or more.
- If such a pipe is installed at a distance from the ridge exceeding 3 meters and is located close to the eaves, then its height must correspond to the level of the ridge.
- Pipe brought to flat roof, should rise above its surface by at least 50 centimeters.
- The ventilation pipe located near the chimney is made of a similar length.
- The more complex the roof configuration is, the more ribs, slopes and valleys it has, which means it requires large quantity outlets providing efficient exhaust.
- In regions with harsh winters, ventilation ducts must be insulated to prevent the structure from freezing at sub-zero daily temperatures.
- When installing pitched aerators, special attention should be paid to the tightness of the joints, since moisture can penetrate through them, which over time can destroy the roof pie and its rafter system.
- It is necessary to select the elements of the ventilation system so that they are made by the same manufacturer, and then the products will complement each other optimally.
Natural roof ventilation
The creation of such ventilation does not require energy costs, so its arrangement is preferable. However, recently, roofs of complex architecture are being erected more and more often. They lack natural roof ventilation and then there is a need to create a forced system.
The structures of almost all types of roofs, consisting of several layers that form a roofing pie, require ventilation. The passage of air currents through the gaps between the individual layers protects insulation material from the accumulation of condensed moisture on its surface.
Some developers believe that protecting the insulation with waterproofing on one side and vapor barrier on the other is enough to prevent water from getting on it, and do not care about arranging ventilation ducts, especially since building codes They do not standardize methods for arranging roof ventilation systems. This fairly common mistake leads to a significant deterioration in the thermal insulation properties of the insulation, rotting of wooden structures and a reduction in the service life of the roof as a whole.
Where does moisture in roofs come from?
Where can moisture come from in a practically hermetic space? First of all, a certain percentage of moisture is always present in the air, and when high humidity during fogs or rains, as well as in heated air interior spaces it increases significantly. Some amount humid air passes through a vapor barrier, some through foam concrete or brickwork etc. It is almost impossible to create a vacuum between layers where air does not penetrate. Water vapor, under the influence of temperature changes, condenses on cooled surfaces, penetrates the insulating material, and destroys wooden structures. Thus, ventilation of the roof and under-roof space, with rare exceptions, must be organized.
Roof ventilation device
The most common and effective type of roof ventilation is the installation of special ventilation holes in the ridge and under the overhangs of the roof structure. Under the influence of wind and temperature changes, air enters the openings under the overhangs, passes through the ventilation gaps between the insulation and waterproofing and exits through the holes in the ridge. The size of the ventilation gap depends on the roof parameters and is on average 5 cm; for roofs with a slight slope - 8 cm. Such ventilation is natural, that is, it does not require additional equipment for air injection. If the system is performed correctly, the air flow can completely pass along the entire roof twice in 1 hour.
There are other ways of arranging ventilation, for example, exhaust openings are made not on the ridge, but on the slopes using special elements. For tiles or other piece roofing materials, special tiles are produced that have ventilation holes.
Roof ventilation through dormer windows
Another option is dormer windows on the slopes. This is one of the oldest methods of ventilation, which has recently been rarely used on its own - only as an addition to ventilation gaps. The fact is that when using such windows, unventilated areas are formed around the windows themselves. To make ventilation as efficient as possible, you need to make two windows - one opposite the other. Their size is usually 0.8x0.6 m. Windows are made during the installation process rafter system, their frame is attached to the rafters using racks. The canopy above them and the “walls” are most often covered with roofing material, the same as the entire roof. “Walls” can also be lined with plastic lining. After production is completed, the opening is filled window frame or ventilation grille. When choosing the size and location of dormer windows, you need to take into account the design features of the roof and its appearance; you do not need to install them too close to the eaves or ridges. Distance between dormer windows on one slope there should not be less than 1 m, the total number of windows should be reduced to the optimal minimum, because they greatly complicate the process of installing the rafter system.
Other ventilation options
As an option, you can consider organizing a forced ventilation system using turbines or deflectors. They are mounted in such a way that it is possible to extract air directly from the under-roof space.
If the roof design provides for a small angle of inclination of the slopes, care must be taken to protect the ventilation openings from snow drifts. Usually in these cases, instead of exhaust holes, pipes are used, the length of which is chosen above the snow layer.
The method of ventilation also depends on the purpose of the under-roof space. For non-residential attics, openings along the eaves and ridge, as well as gable windows, are sufficient. For attic ventilation, aerators are often additionally used - elements that increase air exchange.
Ventilation of roof insulation
How does ventilation of the insulation layer occur and is it really so important to keep the insulation dry?
First, a few words about roof insulation. The thermal insulation layer is the thickest in the roofing pie; the overall thickness of the roof, as well as its energy-saving properties, largely depends on it. High-quality insulation allows you to create and maintain the most comfortable microclimate inside the house, regardless of weather conditions. Depending on the climatic region of the building, the thickness of the insulation can vary significantly. On average, it can fluctuate between 10-15 cm.
Almost all insulation materials absorb moisture, which significantly impairs their thermal insulation capabilities, since water, which conducts heat well, pushes out air. Even with 5% moisture, the insulation loses 50% of its properties. Ideally, the thermal insulation layer is protected on both sides by hydro- and vapor barriers, as discussed above, but even they are not able to completely isolate the insulation from the ingress of steam and its condensation. That is why the surface of the insulation must be constantly dried with a flow of air, preventing drops of moisture from settling on its surface. To do this, there must be a gap between the insulation and the waterproofing layer, which is formed by the counter-lattice boards. Air enters the gap through holes in the eaves overhangs and exits through holes in the ridge. If stingrays have large area or a slight slope, for more efficient ventilation you can use deflectors to create forced draft.
What are vents and why are they needed?
Ventilation openings through which air enters the ventilation gaps and exits are called vents. As you might guess, there are cornice and ridge vents, depending on their location. It is better to make cornice vents along all the cornices. At their core, these are gaps between the roof and the wall, the width of which is about 2-2.5 cm. There are also point vents, which are not a continuous gap along the eaves, but separate holes. The diameter of such holes depends on the slope of the slope: if the slope is more than 15 degrees, it is 10 mm, less than 15 degrees - 25 mm. All vents must be closed: point vents with grilles, and slotted vents with nets or slats (soffits).
Ridge vents also come in slotted (gap width 5 cm) and point vents. Point blows are made at a distance of 6-8 m from each other. Piece roofing materials have special additional elements with ready-made ventilation holes. For example, when laying natural tiles, the second row from the ridge is laid with special ridge tiles.
Elements of the roof ventilation system can usually be purchased along with the roofing material. Many large manufacturers They produce such additional elements for all types of coatings. They match the roof color, texture, material and, when installed, fit perfectly into general form. Ventilation elements include ridge and eaves vents, exhaust openings, and passage channels.
Exhaust openings located closer to the ridge are of several types: in the form of a gable grille on the gables, or a roof outlet on the slopes. The hood can also be placed on the ridge itself in the form of an aerator. For effective ventilation, the area of the exhaust openings should exceed the area of the supply openings by 10-15%, which will increase draft. The total area of the vents is selected at the rate of 1/300-1/500 of the area of the under-roof space. In other words, for 200 m2 of attic area, you need to provide a number of vents with a total area of at least 40 cm2.
Roof aerators
One type of exhaust vent is an aerator. In principle, this is the same hole for removing air and moisture, only slightly “cultivated”. In appearance, aerators are pipes covered with umbrellas, installed near the ridge. The principle of their operation is no different from conventional vents: air also enters the under-roof space through the eaves vents and rises upward under the influence of pressure and temperature differences. Aerators are continuous and point, and the latter are pitched and ridge. Point aerators are used for local ventilation of individual areas attic spaces. Their more modern models have a mushroom shape and built-in fans to create additional draft in the system.
Continuous aerators provide ventilation of the entire under-roof space and are placed along the entire ridge. These are usually plates with exhaust holes hidden by the roofing material. Such aerators are practically invisible from the outside.
The choice of aerator type depends on the type of roof, roofing material, purpose of the under-roof space. There are aerators for flat roofs, natural, bitumen tiles, metal tiles, as well as universal models. They, like other ventilation elements, are often sold together with roofing materials.
Why are roofing passage elements needed?
Pass-through elements or simply penetrations allow you to install fans and ventilation ducts on any roof, while ensuring the tightness of the unit due to seals. Passage elements are selected depending on the roofing material, roof structure and diameter ventilation passage. Manufacturers of roofing materials produce penetrations for tiles, soft roofing, metal tiles, and seam roofing. Penetrations may differ from each other in the elements abutting the roof and in the method of installation. They are usually installed in parallel with the installation of roofing material, but some models can be installed on a finished roof.
Ventilation of the under-roof space
In accordance with regulatory technical requirements, all rooms are equipped with an air exchange system. To ensure normal draft, the exhaust pipe must end above the ridge of the house. Accordingly, it is necessary to equip a ventilation outlet on the roof of the building. Considering that the roof itself and the outlet pipe of the ventilation shaft have a number of structural features and are made of various materials, then the installation ventilation pipe on the roof requires compliance with a number of rules. One of them is to achieve maximum tightness of all connections, since the safe operation of the house as a whole depends on this.
Reasons for installing ventilation on the roof
The end of the ventilation system above the roof of the house is explained by the following reasons:
- the need to create draft to ensure adequate air exchange in the interior;
- installation of a competent ventilation scheme.
Building regulations require complete ventilation of living spaces. If everything was taken into account correctly in the construction project, then you can find exhaust vents on the walls in the toilet, bathroom, wardrobe or pantry, as well as the kitchen. They are necessary to eliminate unpleasant odors, combustion products and excessive humidity from the premises. So that everything negative factors were removed from the house, it is necessary to organize the end of the ventilation shafts outside the building above the roof. Otherwise, they will again enter the house with the flow of incoming air.
Ventilation pipe installation
Types of ventilation pipes
The roof ventilation pipe itself is divided into several categories. First of all, the cross-sectional shape of the ventilation ducts differs:
- round;
- rectangular;
- non-standard.
In the production process of ventilation ducts can be used different kinds materials. The most popular are aluminum, stainless or galvanized steel, polyester-based fabric and plastic.
Primary requirements
A number of requirements are imposed on the ventilation system, which do not bypass the air duct itself. You can find them in the list below.
- The minimum cross-sectional diameter that has ventilation duct, is fifteen centimeters. A galvanized air duct with these parameters shows good efficiency work.
- In the process of setting up the system supply and exhaust ventilation it is necessary to ensure the increased annular rigidity of the pipeline in the design of the outlet part. The reason is the following - in an area that rises above the roof, the pipe constantly faces significant wind load. Therefore, the design must cope effectively with it.
- The ventilation pipe must have an increased safety margin while simultaneously having a minimum wall thickness. The smaller the thickness, the higher the overall throughput.
- Metal ventilation ducts should not become covered with a layer of rust over time. There are moisture vapors in the room that settle inside the pipeline. They should not cause the development of corrosion processes.
- The exhaust pipe itself should not emit harmful gases during operation and not become a source of fire spread.
- The structure must have a minimum weight.
It is worth noting that brick and galvanized ventilation ducts fully comply with almost all the qualities mentioned above. The brick pipeline has a weight corresponding to regulatory requirements. Metal pipe during operation it is capable of attracting dust, as static electricity accumulates on the walls.
Ventilation outlet to the roof
Stages of installation work
Before installing the ventilation pipes on the roof, it is necessary to complete the installation of the ventilation system wiring inside the building. The air duct itself must be securely fixed. The list of tools depends on the roofing material of the house. To carry out the work comfortably, you will need the following basic list of tools and materials:
- chisel;
- electric drill;
- building level;
- jigsaw (highly preferably electric);
- Screwdriver Set;
- insulation material;
- metal scissors or grinder;
- marker;
- hardware for fixing;
- sealant;
- rags;
- pass-through unit;
- individual protection means.
By doing self-installation ventilation exits to the roof, you should use the assembled passage unit, thereby greatly simplifying your work. The sequence of actions is as follows:
- Marking. Using a marker, make marks according to the template (depending on the cross-section and size of the ventilation outlet pipe to the roof) in the place where the ventilation shaft will exit.
- Creating a slot. You need to cut a hole in the roof using a tool for processing a certain roofing material (usually a grinder).
- Removing the top layer of the roof.
- Drilling holes for fastening the outlet segment of the ventilation shaft.
- Marking for installation of the passage unit.
- Creation of grooves into which self-tapping screws will be placed in accordance with the previously made markings.
- Installation of the passage unit.
- It is fixed using self-tapping screws.
- Installation of the ventilation pipe, securing it using appropriate hardware.
- Insulation of all cracks and openings.
Installation Features
During planning and installation of the ventilation system, it is first necessary to check the calculations for compliance technical rules. It is strongly recommended to entrust the design to specialized specialists who understand all the features and technical nuances building.
There is a difference in temperature at the inlet and outlet of the ventilation duct. An increase in draft occurs inside the channel due to the difference in temperature inside and outside the room. This is the main reason that winter period ventilation tends to work with higher productivity than in the summer.
Even at the design stage, you need to think about the thermal insulation of the channels that run under the roof. This is required so that the air draft does not decrease over time. This solution effectively protects the exhaust ducts from moisture accumulation. If the ventilation pipe is located along the chimney, it is necessary to take care of its heating (the quality of operation of the ventilation system as a whole changes positively). On the other hand, there is also a minus here. In such channels, the draft is different, so if the calculations are made incorrectly, you may encounter a malfunction of the ventilation.
Properly designed ventilation outlet contributes to effective air conditioning indoors. Self-installation does not cause difficulties, provided that you are familiar with the specifics of the work in advance.
Securing the top of the ventilation riser
Consequences of installation errors
Proper installation of a ventilation pipe on the roof is the key to full-fledged work the entire system. Failure to comply with recommended installation standards will result in the following negative consequences:
- weakening of traction;
- the presence of unpleasant odors in residential premises;
- accumulation of moisture in rooms;
- condensation inside the system;
- lack of oxygen;
- the appearance of fungus on the surface of the walls;
- soot deposits on facing materials installed in the kitchen;
- increasing the incidence of diseases in all residents;
- freezing of certain building structural elements.
Correct installation is the main factor that determines the usefulness of air exchange and living comfort.
