When building a house, it is very important to properly arrange the roof: reliably insulate it and insulate it. No less important is roof ventilation, which allows the steam generated in the house to be removed into the under-roof space.
If this is not provided for, then moisture will settle on the roof elements, gradually rendering them unusable and destroying the supporting structures of the house.
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Consequences of poor ventilation
Not all owners of private houses decide to install a roof ventilation system, thinking that there is no particular need for it. Nevertheless, it is needed in every building in which at least someone lives. When people and animals sweat and breathe, wash, wash, cook, clean, and other processes that use water, water vapor is released.Under the influence of the laws of physics, he finds himself under the roof, from where he cannot escape, since the roof is always vapor-tight. Therefore, to get rid of steam, special devices are needed.
If no measures are taken for this, steam will condense on the cold inner part of the roof, leading to various consequences. Here are some of them:
- In winter, ice will form, which can destroy the roofing elements and the shafts and pipes built into it;
- the roofing material can be damaged - if it is metal, then rust will form on it, and if it is ceramic, then you should expect mold to appear;
- thermal insulation materials, for example, mineral wool, will become saturated with water and lose their beneficial properties;
- All wooden structures, exposed to water, will gradually begin to rot.
To prevent all this from happening, a ventilated gap is installed on the roof, and the attic space is ventilated.
A ventilated ventilation gap in the roof allows steam to escape from the building to the outside. In addition, it has additional useful features. In winter, it promotes uniform heat distribution along the slope, preventing water from melting and the formation of icicles. In summer, it creates a kind of protection from the heat: thanks to it, the heat from the hot roof will not penetrate into the house.
Similar holes are installed in dormer windows, under the ridge of the roof and on eaves overhangs. To ensure effective air circulation through them, various roof ventilation devices are used. They are not always needed in small or medium-sized roofs, where natural ventilation is sufficient, but on large roofs they are simply necessary.
Roof ventilation from Metal Profile
Main components
There are several basic elements of roof ventilation. They should be selected depending on the type of roof. There is no need to save on their purchase: as a rule, they cost no more than 2-5% of the cost of the roof, including installation. The scale of their functionality is much higher, and with them the roof will last much longer without repair.
Roofing tape. This tape reliably protects the under-roof space from the penetration of dust, dirt, small birds and other living creatures. With its help, you can close all the cracks and at the same time provide ventilation to the inside of the house. Such tapes come in perforated eaves (for overhangs) and ridge tapes.
Ridge tapes protect the roof from the effects of precipitation in any weather and remove steam to the outside, which negatively affects the covering material and the rafter system. High-quality varieties are also impregnated with a composition that repels ultraviolet rays and provides reliable protection from solar radiation. Usually they are laid along the edge of the roof, and then the ridge is mounted on top.
The air temperature during these works should exceed 5 degrees Celsius. Perforated cornice strips cover the overhangs of the cornices. In addition to other properties that are inherent in both types, this tape also increases the strength of supporting structures.
Safety net
One of the main problems of a pitched roof, in addition to air exchange, can be called insect infestation. If you do not properly protect your home, hornets and wasps, as well as small birds, will fly into your home.They can not only visit a home once, but also build a nest and start living there. Removing a wasp nest is not an easy procedure, and it is better not to let it get to that point. It is precisely to eliminate such troubles that an anti-mosquito net with cells no larger than 2-3 millimeters is designed.
It is best to lean towards stainless steel mesh, which is considered to be the most durable and durable. It differs from analogues in its long service life and increased resistance to corrosion. In addition, it fits well into the interior of the house. The only noticeable disadvantage is its high cost. It is not advisable to replace a stainless steel mesh with a regular steel one. This material will be susceptible to corrosion due to accumulating condensate, and will gradually rot and rust.
A more suitable budget option is a fine mesh painting mesh. Its main advantage is ease of installation: it is attached with an overlap, attaching it to the roof parts with a regular stapler.
However, this is still a temporary option: it is not very durable and is easy to tear. Birds also easily peck at it, so over time it is necessary to update the product or replace it with one more resistant to external influences.
Pass-through elements
The passage elements of the ventilation system (penetrations) are included in the pipes. They are used to seal holes in the roof. Usually they are not included in the kit, but are specially selected separately.Penetrations come in different shapes, colors and sizes. These parameters depend on the manufacturer and the material with which the roof is covered (corrugated sheeting, soft roofing, metal tiles). They can be installed both during the construction process and after its completion on the finished roof.
They are very easy to install. The only difficulty is to select suitable elements - the ability of the ventilation system to withstand any climatic changes, the durability of ventilation and the absence of leaks in the areas where they will be embedded depend on this.
Forced aeration
In many cases, natural ventilation is sufficient to remove steam, but sometimes it is necessary to install forced air elements - aerators. They are usually installed on soft roofs. They reduce pressure and increase draft, making high-quality ventilation possible.
To select and install aerators correctly, the following rules must be followed:
- the distance between two adjacent devices must be at least 12 meters;
- so that the entire under-roof space is ventilated evenly, you need to install them along the entire length of the roof on the highest sections of the slopes;
- to prevent dirt, dust and insects from getting inside, you need to install special filters on them;
- aerators are attached to anchor bolts or dowels;
- You can use special tape or sealant to close gaps and avoid leaks.
In addition to aerators, for the same purposes, an overhang ridge with teeth can be installed to protect the gap and the under-roof space. Roof fans are also often used - they are good on pitched roofs, where natural ventilation is impossible, and on flat roofs, where ventilation is not strong enough.
Rules for installing aerators
The conditions for installing aerating devices depend on what material the roof is made of. They must be followed to ensure that the house is optimally ventilated.
Installation on a tile roof. Ventilation of metal roofing can be done using aerators or mounting. At the same time you need to follow certain rules:
It is best to carry out this operation in good sunny weather. If it rains, the final quality may suffer.
The process of installing an aerator on a roof with soft tiles is almost no different from working with a metal-tiled building. However, the installation methods are still not completely identical.:
- 1. Using the template attached to the aerator, the outline of the future cut is drawn in the coating.
- 2. The covering is cut through to the waterproofing barrier.
- 3. The edges of the hole are coated with sealant, after which a fully assembled mushroom aerator is installed into it. Its casing is screwed on using self-tapping screws.
- 4. The outside of the casing is coated with bitumen and covered with soft tiles.
Mounting on corrugated board
To ensure ventilation of a corrugated roof using aerators, a wooden box is usually used.
In this case installation consists of the following steps:
- 1. Markings are applied to the corrugated sheet at the location where the aerator is installed.
- 2. A cross cut is made in the marked area.
- 3. The petals resulting from the cut are bent down and nailed to the wooden structural elements with nails.
- 4. A box corresponding to the size of the opening is knocked together from the boards. It is inserted into the hole and screwed with self-tapping screws to the rafter system.
Since many roof materials do not tolerate moisture well, you need to carefully consider the selection and installation of roof ventilation. This will extend the life of the building and improve the internal climate in the house.
When building a house, it is imperative to consider high-quality roof ventilation. This is one of the main tasks of designing and constructing a durable home. Without a good ventilation system, the entire roof structure will very quickly become unusable. Moisture will primarily damage all wooden elements, which will reduce the safety and comfort of the building. Then the roofing material will begin to deteriorate. Let's take a closer look at the issues of ventilating the roof of the house and natural ventilation of the roof.
Where does moisture come from in the roofing “pie”?
The roof of a residential building is a complex system consisting of a wooden frame, roofing, as well as layers of waterproofing, vapor barrier, and thermal insulation. In general, a high-quality roof is a sealed package. But moisture still gets onto the wooden elements and insulation. The fact is that air containing water vapor penetrates inside the roofing pie. When the temperature changes, steam settles in the form of condensate on the surfaces of the inner layers.
Even through the most reliable vapor barrier made of steam and waterproofing, some air still penetrates inside the “pie”. In addition, air can enter through "breathable" wall materials such as porous blocks, wood or cellular concrete. Therefore, condensation cannot be avoided. This phenomenon is especially pronounced during precipitation or fog, when the concentration of moisture in the air increases noticeably.
Purpose of roof ventilation
The ventilation system of the roofing system simultaneously performs several important functions, which increases the comfort of living in the house and extends the service life of the roof.
The main function of ventilation is removal of vapors from the under-roof space, which rise from residential premises. During the ventilation process, circulating air prevents moisture from accumulating on the inner surface of the roofing pie, from where it can penetrate into the roof.
The movement of air masses in the roof ensures not only the weathering of excess moisture, but also uniform temperature distribution. As a result, all elements of the “pie” warm up quite well during the heating season. Therefore, a roof with good ventilation is less likely to become overgrown with icicles, which create additional stress on the roofing.
In summer, ventilation is necessary for roof cooling. This is especially important for houses with soft roofing, which gets very hot and can melt and slide even with a high slope.
Natural and forced ventilation
For their long and uninterrupted operation, both types of ventilation systems require careful calculations, which will show which one is better to use in terms of efficiency and economy. When making calculations, specialists must take into account the features of these systems.
Natural ventilation
It is carried out due to the convective flow, which arises as a result of the interaction of warm and cold air masses. For such ventilation to work, you need to assemble a roofing pie with a gap (at least 5 cm) between the bottom waterproofing layer and the roofing layer.
Effective natural roof ventilation is possible with proper design and competent work of builders. It is not easy to create conditions for it. It is necessary to carefully calculate the system of lathing and counter-lattice, and ensure the continuity of the ventilated circuit. But most importantly, it is necessary to provide ventilation vents. There should be at least two of them in the ridge area and the same number in the cornice area.
The air in the under-roof space heats up and naturally rises upward, where it is forced out through the ridge vents. Fresh air enters through the eaves openings. Thanks to this process, condensation does not settle on the roof surface.
If the slope of the slopes is small, in winter the ridge vents may be clogged with snow. To prevent this, you need to install special pipes along the ridge that will rise above the snow level.
Forced ventilation
Since organizing artificial ventilation requires additional equipment, from a technical point of view this is a more complex option. There are rare exceptions when designing forced ventilation is easier than calculating natural ventilation, but these are still exceptions that prove the rule.
It became widespread as a result of the fact that, firstly, low and completely flat roofs came into fashion, in which it is simply impossible to create natural ventilation. Secondly, new construction technologies have emerged that make it possible to automate and improve the maintenance of cottages.
Forced systems are installed not only in houses with flat roofs, but also in houses that, for one reason or another, cannot be provided with roof vents. Recently, more and more often, solid cottages with standard roofs are equipped with forced ventilation, since it is more reliable than natural ventilation.
Forced ventilation can be carried out by installing a fan in the ridge vent. To do this, you need to stretch a wire into the upper part of the roof. The second option is to install special devices that increase the intensity of air movement.
On our website you can get acquainted with the most popular ones from construction companies presented at the exhibition of houses “Low-Rise Country”.
Methods for arranging ventilation
Roof ventilation can be provided in different ways. The choice of arrangement option depends on the architectural solution of the designer.
Aerators
Installing roof aerators is the most common option. The aerator is a piece made from a small piece of pipe with a flat base for installation on the surface and an umbrella that covers the upper hole of the pipe from precipitation. A protective filter is placed inside.
Aerators can be installed in various ways. The location of these devices depends on the type of roof and the degree of humidity in the region. Typically, aerators are located near the ridge. You can install them point by point. Experts believe that the most effective is to install a continuous aerator gutter stretched along the entire edge of the roof. It is advisable to install this type of ventilation simultaneously with the installation of the ventilation system of the entire building.
The advantage of aerators is that they do not interfere with the design of the house. In addition, when using them, the roofing covering does not have to be sealed, that is, it can be laid without the use of special tape and foam.
On our website you can find contacts of construction companies that offer roof repair services. You can communicate directly with representatives by visiting the “Low-Rise Country” exhibition of houses.
Ventilated cornice
The use of a ventilated eaves provides air access to the under-roof space. As a result, the roof is well ventilated, and the entire ventilation circuit of the building works better. The eaves for roof ventilation can be arranged in different ways:
usage spotlights for roofing;
installation ventilation grilles;
installation of special eaves over eaves elements with vents.
Insulation materials are not laid in the places where the eaves ventilation channels are installed. To protect them from precipitation, elements of the drainage system and snow retainers are used.
Dormer window
Ventilation using a dormer window is also a fairly common option. Ventilating the roof of a house using this method, among other things, improves the aesthetics of the facades. Windows can be different in shape, and it is important at the design stage to think about the type of windows that will correspond to the overall style of the building.
Dormer windows are roof elements that are quite expensive to construct. But they have their undeniable advantages - high efficiency as a ventilation system and aesthetic appearance.
Ventilation of roofs made of metal tiles and corrugated sheets
These are the most common roofing materials in our country. They are very convenient in terms of application technology and price. They are manufactured using the same technology and differ primarily in shape. Corrugated sheeting looks less impressive, but at the same time has stiffening ribs along its entire length.
In the process of installing a metal tile or corrugated roof, difficulties arise with ventilation. The fact is that these materials are absolutely vapor-tight and thermally conductive. They heat up and cool down quickly, causing a lot of condensation to accumulate on the inside. But these materials also make it possible to create high-quality roof ventilation - roof ventilation, which extends the service life of the entire building.
Manufacturers of metal tiles and corrugated sheets produce special additional elements with which ventilation passages are equipped. The main thing is to entrust the installation of the roof to specialists who will think over a good ventilation system. Since these materials do not retain heat very well, when using them, additional layers of hydro and thermal insulation are provided. In addition, these roofing materials themselves must be protected from moisture with special care. Due to these features, roofs made of metal tiles and corrugated sheets are often equipped with forced ventilation.
Ventilation of soft roofing
When exposed to high temperatures, soft roofing can swell and melt. Therefore, it is so important for it to have ventilation that will not only remove moisture from the roofing pie, but also cool the roof during the summer heat. Typically, roof ventilation, the roof of which is made of bitumen tiles, is equipped with the help of aerators (vents).
Video description
Roof ventilation using valves (aerators)
Attic roof ventilation
The ventilation system of the attic roof performs an additional function - regulating the temperature in the rooms of the upper level of the house. It is designed more carefully than roof ventilation above the attic. On the other hand, it is easier to protect the attic roofing pie from moisture, since attic spaces, unlike attics, are heated and well ventilated.
In most cases, forced roof ventilation is not required to remove condensation from the attic roofing pie. But between the waterproofing and thermal insulation layers, space must be provided for the unhindered passage of air.
Video description
How to properly ventilate an attic roof
If the attic is being converted into an attic
A simple attic can be converted into an attic to expand the living space. In this case, the roof is usually re-roofed. Insulation and roofing materials are replaced with higher quality ones. More efficient ventilation of the roofing pie is being installed. However, if the roof was originally laid very well, you can improve it a little without disassembling it.
Any roof has at least a very small gap in the sheathing. It needs to be turned into a ventilation duct. This is achieved by installing special pipes in the roof plane through which the steam will ventilate. Closer to the ridge of the roof, holes are made with the calculation of 1 pipe per 50 sq. meters of roofing. Each such element must be protected from precipitation. As a result of installing a pipe vent system, ventilation on the roof will become more intense.
Video description
How to turn an attic roof without a ventilation gap into an attic
Stages of work
The process of arranging a ventilation system for any roof consists of several main stages. The first step is to provide for the presence of ventilation elements in the roofing system design. After this, during the construction of the roof, roof ventilation ducts and openings are made. In case of forced ventilation, special ventilation equipment is installed. At the last stage, the ventilation holes are protected from precipitation and dirt.
Conclusion
The roof of a private house must be well ventilated, otherwise the elements of the roofing pie will be negatively affected by condensation. They will quickly lose their original technical characteristics, and there will be a need for replacement. In addition, without high-quality roof ventilation, the rooms of the house will be damp, and heating will require more energy consumption. Therefore, it is very important to correctly design and correctly construct a roof with an effective ventilation system, taking into account the type of roof structure, type of roofing material, climatic conditions of the region and other important factors.
Living spaces in the attic can be as comfortable as those on other floors. But in order to create comfortable conditions here, it is necessary first of all to insulate the roof, and also (no less important) to take measures to install reliable waterproofing and ensure effective ventilation. At the same time, two important conditions must be met with regard to the roof structural elements: protect them from moisture ( inside and outside) and ensure its removal in case of penetration.
Causes of moisture
The roof over an unfurnished attic, consisting of rafters, sheathing and roofing, does not require the measures discussed here. The attic floor is constantly ventilated, the temperature and humidity of the air inside the attic practically do not differ from the corresponding indicators of the outside air, and if they differ, it is insignificant.
Rice. 1. When laying thermal insulation between the rafters, it is better to use their entire depth. A second, thinner layer of thermal insulation, laid below the rafters, increases the insulation efficiency. Red color indicates under-roof waterproofing, and blue color indicates vapor-proof film.
The picture changes when installing thermal insulation, which separates the internal environment from the external one. In this case, the temperature and humidity of the air inside the attic floor and outside begin to differ significantly. Therefore, problems arise that force us to take additional measures to protect roof elements.
One of these problems- an increase in air humidity resulting from human activity. When cooking and washing, washing and wet cleaning, breathing and sweating, the air is saturated with moisture in the form of particles of invisible steam (unlike the steam coming out of a boiling kettle, which we can observe). This moisture, together with warm air, rises, accumulates there or escapes out through leaks in the roof.
The amount of moisture in the form of water vapor that the air can absorb depends on its temperature. The warmer the air, the more moisture it contains per unit volume. When the temperature drops sharply, the air can no longer retain this moisture, and it falls out in the form of water droplets.
The same phenomenon can be observed and when water vapor penetrates from living spaces into structures, where it comes into contact with the colder lower surface of the roof. This leads to the appearance of condensation droplets on it. Moisture spoils the appearance of structures and finishes, worsens the thermal properties of insulation, and provokes putrefactive processes.
Rice. 2. A vapor-proof layer is necessary to prevent the penetration of water vapor from the attic to the roof elements. 1 - relative humidity 50%; 2 - relative humidity 80%.
Rice. 3. Moist air from the interior of the house can penetrate through loose joints of the vapor barrier to the roof elements. When the air cools, condensation forms here with all the ensuing consequences. Therefore, it is very important to lay the vapor barrier as tightly as possible.
Penetration of moisture to roof elements is facilitated by, for example, inaccurate laying of a vapor-proof layer on the inner surface of the insulation, insufficient overlap of vapor barrier strips, their loose connection to walls and pipes, accidental ruptures and other circumstances. Therefore, the first thing you should take care of when insulating the roof is installing a reliable vapor barrier on the interior side. On the roof side, the insulation must be protected from moisture by a layer of waterproofing, which is laid along the rafters or on a special flooring.
This double-sided protection of an insulated roof is quite reliable., but even this is not enough. It is also necessary to create conditions for the removal of moisture that accidentally penetrates here. And this is achieved, as a rule, due to air circulation in two cavities, one of which is located between the roof and the under-roof waterproofing layer, and the other between the under-roof layer and the thermal insulation. But the air circulation system, naturally, can function only if there is a free flow of air into these cavities from the street and its removal. To do this, vents are installed in the roof overhang and in the upper part of the roof.
Rice. 4. So that air can circulate freely between the roof and the layer of under-roof waterproofing, counter battens are laid along the rafters, the thickness of which determines the size of the air cavity. Air enters this cavity through holes in the side overhangs of the roof: 1 - under-roof waterproofing; 2 - counter-lattice; 3 - thermal insulation; 4 - vapor-proof layer.
Rice. 5. To allow air to escape from the cavities above and below the layer of under-roof waterproofing, so-called ventilation tiles are laid near the ridge or gaps are provided when installing the ridge itself: 1 - ventilation tiles; 2 - skate; 3 - under-roof waterproofing; 4 - vapor-proof film.
Thermal insulation materials
The most popular thermal insulation materials for roofs are mineral fiber mats, polystyrene foam and polyurethane foam boards. All of them must have hygiene certificates. Typically, the labels of these materials contain data confirming their suitability for use indicating the thermal conductivity group, which is usually equal to 0.40 or 0.35 W/(m-K). To achieve the required thermal insulation value, you can use either a material of thermal conductivity group 0.35 of a smaller thickness, or a material of a thermal conductivity group of 0.40 of greater thickness.
Rice. 6. Insulating the roof with laying thermal insulation between the rafters. Under-roof waterproofing is installed along the rafters (above) or over a solid wooden flooring (below): 1 - under-roof waterproofing; 2 - counter-lattice; 3 - sheathing; 4 - thermal insulation; 5 - vapor barrier; 6 - ventilation tiles; 7 - ventilating ridge; 8 - wooden flooring.
Methods of roof insulation
You can insulate a roof, the frame of which is a rafter system, in one of three ways: by laying insulation between the rafters, on the rafters, or under the rafters. Most often, thermal insulation is laid in the simplest way - between the rafters.
The insulation must be continuous, including in areas adjacent to walls, chimneys and windows built into the roof plane. The width of the air gap between the thermal insulation and the under-roof waterproofing should be at least 2 cm in all areas of the insulated surface. At the same time, attention should be paid to ensuring that the waterproofing material does not sag too much, which would become an obstacle to effective air circulation. When using mineral fiber mats as insulation, you must also take into account the fact that after installation, the thickness of this material can increase by 10-30%.
The vapor-proof film on the inside of the insulation prevents the penetration of moisture into the structural elements of the roof and walls.
If the depth of the rafters is less than necessary for laying thermal insulation without compromising air circulation, they can be increased by nailing overlays from boards or bars. Another option is to divide the insulation into parts and lay one part between the rafters and the other under them.
The modern market offers insulation systems, assembled from heat-insulating panels, which already provide waterproofing. The use of such systems makes it possible to refuse one of two levels of air circulation, since in this case a layer of under-roof waterproofing is not installed.
The main condition for the normal functioning of such systems is the creation of a reliable vapor-proof layer on the inside of the roof.
Rice. 7. Insulation of the roof with installation of thermal insulation under the rafters. Under-roof waterproofing is installed along the rafters (above) and along continuous wooden sheathing (below).
Rice. 8. Laying thermal insulation above the rafters on solid wood sheathing with a waterproofing protective layer. Here, only one level of air circulation is required - between the thermal insulation and the roof. The air cavity is created by a counter-lattice, the slats of which are laid parallel to the rafters: 1 - wooden sheathing; 2 - hydro- and vapor barrier; 3 - counter-lattice; 4 - thermal insulation.
Rice. 9. Insulation of the roof with thermal insulation panels in addition to the existing thermal insulation. To create a cavity for air circulation, the distance between the old and new thermal insulation should be 50 mm. Special elements are placed under the top row of tiles to ensure air circulation: 1 - heat-insulating panels; 2 - previously laid thermal insulation; 3 - thermal insulation elements that provide ventilation.
Such thermal insulation is laid above or below the rafters, connecting the individual elements into a rebate. The disadvantage of the lower position of the panels when insulating the roof is the reduction in the volume of the attic floor to be equipped.
When insulating the roof from the upper side of the rafters, the roof structural elements are located indoors and are reliably protected from atmospheric and temperature influences. This method is also interesting because it allows you to use open rafters when creating an interior.
Preparing the roof frame
Isolating a roof from moisture and insulating it is quite a complex job, therefore, before starting it, you should make sure that the rafter system is in good condition and, if necessary, carry out its sanitization. Often, wooden roof elements, especially in old houses, are affected by pests. This can be judged by the presence of wormholes in the wood. If they are detected, the infected wood must be treated with chemical protective agents, after consulting with a specialist. Severely damaged structural elements are replaced.
Rafter structures, especially in old houses, also need to be checked for statics. And here you cannot do without the help of a specialist.
Ventilation of the roof of a house is necessary, as is ventilation of the attic or bathroom. On the surface of a non-ventilated roof, the temperature and humidity conditions are disrupted. Drops of condensation settle on the roofing material and supporting structures, causing rot, destruction and leading to frequent repairs.
Why is roof ventilation necessary?
Due to temperature changes, condensation collects in the under-roof space. Water penetrates the insulation and its insulating qualities deteriorate. The more moisture there is under the roof, the worse it holds the temperature.
Most often, the rafter system is assembled from wood, which is susceptible to rotting due to constant contact with moisture. Mold-covered rafters are collapsing, threatening to collapse.
The accumulation of water in roofing carpet made of soft materials causes peeling of the coating. The roof starts to leak. And only roof ventilation will help prevent all troubles.
Advantages of houses with ventilated roofs:
- the under-roof space is purged with fresh street air;
- optimal temperature and humidity are maintained in the attic;
- the properties of the heat-insulating material are preserved;
- roofing materials and supporting structures are protected from mold, mildew, and sagging.
Poor roof ventilation in a private house causes:
- wetting of the truss structure, rotting, deterioration of load-bearing properties;
- deformation or rusting of roofing material;
- destruction of stone and concrete parts;
- a decrease in the thermal insulation qualities of the roof, which means an increase in the cost of heating the house;
- overheating of the house and roof during the hot season.
In this regard, the importance of ventilation of the attic roof, where the under-roof space is residential, should be mentioned.
Roof ventilation methods
Ventilation of the roof of any private house is carried out using the method of natural air movement in the under-roof space.
There are several mechanisms for ensuring roof ventilation in a private house:
- ventilation of the ridge of a gable roof.
- cornice ventilation.
- roof exhaust fans.
- piece elements with ventilation holes.
- specially designed skates.
- ventilation gaps that are provided when installing the roof.
- dormer windows in the attic.
Now let’s look at the features of different roof ventilation designs, assembled from different materials.
Flexible tile roof ventilation
When laying flexible tiles, be sure to leave a gap for ventilation. But for the free movement of air on both sides of the roof, several more conditions must be met.
Requirements for roof ventilation made of flexible tiles:
- A 50 mm beam is inserted between the insulation and the base of the roof;
- Ventilation slots are left along the bottom of the roof slope, through which fresh air penetrates. This is a favorite habitat for small birds. Therefore, it is advisable to cover the ventilation gaps of a soft roof with grilles or soffits;
- Air exhaust is provided by ridge vents or aerators;
- The lathing is installed in a special way, with gaps, so that air flows freely pass from bottom to top;
- The height of the air gap is determined by the thickness of the beam. Which is chosen depending on the length of the slope and the angle of the roof. Only a specialist can correctly calculate the width of the air gap.
For example, when the length of the slope is 5 meters, the angle is 10 degrees - 5 cm is enough, if the angle is the same, and the length of the slope is 25 meters, you need a beam 10 cm thick.
Ventilation of a soft roof can be done using 1 or 2 circuits. The dual-circuit system is discussed in the accompanying illustration.
1 – insulation, 2 – vapor barrier, 3 – hurricane protection, 4 – the first slot for ventilation, 5 – second slot for ventilation, 6 – roof covering.
Forced ventilation of flexible roofing
To increase the ventilation efficiency of flexible tile roofs, aerators are installed. There is always low pressure in the aerator, so the draft never disappears.
Aerators are available in various diameters and heights. The size and quantity are selected depending on the area of the roof made of flexible tiles.
Ventilation with aerators is equipped according to the following rules:
- there must be at least 12 meters between two aerators;
- they are installed evenly on the highest places of the roof;
- if the roof has recently been installed, it is preferable to choose the joints of the insulation;
- if aerators are installed during the renovation of a soft roof, the best place for the ventilation element is where the roof is slightly swollen;
- the diameter of the hole for the weather vane should be 1 - 2 cm larger than the diameter of the pipe itself;
- the aerator is attached with anchor bolts or dowels;
- the joint must be treated with sealant or special tape applied.
Attic roof ventilation
Roof ventilation above the attic has an additional important function of regulating the temperature inside the residential attic. The lower surface of the roofing pie is actually adjacent to its ceiling. Thus, the movement of air along the internal plane provides additional thermal insulation. Therefore, a special technology has been created for constructing ventilation for attic roofs with the removal of humid, hot or cold air to the outside.
The principles of natural ventilation are used: warm air is displaced by a cold flow coming from below.
Components of attic roof ventilation:
- vapor barrier film or membrane (selected with minimal permeability);
- insulation, which is placed between the rafters;
- sheathing;
- counter-lattice made of slats or bars;
- waterproofing;
- roofing covering.
The diffusion membrane completely prevents the accumulation of condensate. A special membrane fabric prevents moisture from below (from the living space of the attic) from reaching the lower surface of the roof. At the same time, a gap remains under the roofing material for the unhindered movement of air masses. Waterproofing prevents the penetration of moisture from outside.
It is also necessary to provide gaps in the eaves for air entry and in the ridge area for exit. The upper ventilation gap is located between the waterproofing and the roofing. Water entering from the street evaporates through this vent. The structures supporting the roof are also well ventilated.
The lower ventilation slot is located between the waterproofing and the insulating layer. Water evaporates through it, penetrating into the insulation from below. The air from residential premises is saturated with water vapor, which must be removed.
Steam and waterproofing of the roof
Insulating films are laid on the rafters, with gaps of no more than 120 cm between them. To prevent condensation from getting onto the wooden beams, the film is mounted with a sag of 1 - 2 cm. It is secured with a stapler or nails with a wide galvanized head. If the cap is not large enough, the film will break through. The canvases are laid out with an overlap of 15 cm, which is glued with tape.
There should be a gap of at least 4 cm between the insulating layer and the waterproofing. The film is rolled out along the rafters and secured with slats along them, nailed with galvanized nails.
The counter-lattice consists of bars that are installed at intervals of 15 cm.
In the ridge area, it is necessary to leave 5 cm between the edge of the insulation and the ridge axis for ventilation. And only now can you construct a sheathing, the type of which depends on the roofing material.
It is important to properly treat the places where the pipes enter the roofing pie. The film is cut in the form of a truncated triangle. It turns out to be something like valves that are attached to the pipe walls or bars with sealant tape.
The vapor barrier is installed by tension, leaving no bottom gap. But top ventilation between the membrane and the sheathing is necessary.
To protect roofing material from exposure to steam from residential premises, fleecy membranes are used, attached to the insulation with a smooth surface inward. Small hairs hold water droplets without rolling into puddles. Such a vapor barrier extends the life of insulation and wooden structures and preserves the quality of insulation. Thanks to the film, mold colonies do not form on the rafters.
Vapor barrier sheets are rolled out across the insulating material, overlapping by 15 cm, the edges are glued with special tape.
Ridge aerator for ventilation
A ridge aerator provides ventilation to the roof ridge and helps maintain temperature and humidity in the attic. Ready-made ridge aerators can be mounted on any type of roof.
They are installed only on roofs with a slope of 14 to 45 degrees. Ridge vents must be installed on the roof. The length of the aerator must match the length of the ridge. A distance of 30 cm or more is maintained from the chimney to the ridge cut. The structure of the ventilated roof ridge must be airtight.
Deflectors for attic roofs
Deflectors or roofing aerators are mechanisms for removing moisture and steam from the roofing pie. The aerator uses the convection method.
The deflector in the attic roof provides:
- evacuating steam before it reaches roofing materials;
- reducing pressure, preventing swelling of mineral wool used as insulation;
- evacuation of moisture from mineral wool, preventing condensation.
According to the standards for ventilation of mansard roofs, it is necessary to equip 1 deflector for every 100 square meters. meters. This density allows you to effectively remove excess moisture. If the roof valley is very steep and the ridges are inclined, deflectors are placed in the valley and along the ridge girder at the joints of the insulating layer.
Metal roof ventilation
Ventilation of the roof of a metal tile house has some features.
Continuous ventilation is ensured during the installation of the roofing pie and consists in leaving a gap of up to 5 cm between the roofing material and the thermal insulation. The bottom layer of insulation is ventilated thanks to a 5 cm thick gap up to the sheathing. To prevent the wood from getting wet, a sealant is placed under the ridge.
The area of the ventilation slots at the eaves should be equal to the area of the ridge vents (the volume of inflow is equal to the volume of outflow). The total area of the vents should be 1% of the roof area. If during the design and construction of a house the ventilation of a metal roof is not thought out, there is an express method for ready-made roofs.
The basis of roof ventilation in this case is ventilation pipes and ventilation outlets. The height of the pipe should be 50 cm or more. For every 60 sq. meters of roof area, 1 pipe is installed as close to the ridge as possible. By the time of installation of the point ventilation outlets, the video of which we present, the metal tile roof must be completely assembled.
Plastic pipes are most often used; they do not interfere with the appearance of the building and serve for a long time.
In areas with heavy snowfall in winter, pipes up to 65 cm long are installed. The junctions of the pipes with the roof are hermetically sealed. When the roof is flat and the slopes are more than 6 m long, ventilation connections are installed. The height of the junctions is from 40 cm above the roof. Instead of a regular pipe, it is sometimes more effective to use deflectors, shown in the video of metal roof ventilation.
Ventilation of the roof ridge under the metal tile is provided by a ridge board separating the two roof slopes. On one side, air flows out freely, preventing the formation of condensation.
Natural draft is used to ventilate the space under the roof. And it will only work if the number and location of ventilation outlets are accurately calculated.
Installation of point ventilation outlet
Point exits are suitable for ventilation of hip and pitched roofs of a small area. Complex roofs with several ridges are equipped with an exit at each ridge. The distance to the ridge should not be more than 0.6 m. It is not advisable to mount two exits on one sheet of metal tile, so as not to weaken the structure.
When purchasing a ventilation outlet for a metal roof, the following parameters are taken into account:
- the profile of the lining must match the profile of the metal tile;
- pipe color;
- temperature restrictions for this instance;
- the kit should include installation instructions, linings, a template, fasteners, the pipe itself, as well as a passage element;
- The diameter of the pipe depends on the roof area.
The most important point in installing spot ventilation for a metal roof is cutting a hole of the required size and sealing the pipe. If the device is assembled correctly, in accordance with the instructions, then the junction with the roof will be insulated from rain or snow.
The hole is cut clearly according to the attached template using metal scissors or a hacksaw, but not a grinder, which spoils the coating.
The tightness is ensured by silicone, which is used to treat the sealing circle. Next, the passage element is attached with screws from the kit and a pipe is inserted into it. The passage element is necessary to fix the pipe. To make the fastening reliable, a hole is cut in it a quarter smaller than the diameter of the pipe. Sometimes this unit is sold already assembled. The pipe must be installed vertically, which is checked by level. Now it is secured with screws and covered with decorative overlays.
Corrugated roof ventilation
Ventilation of a corrugated roof is organized using a natural method, similar to the ventilation of a metal roof shown in the video. In the area of the eaves overhang, air penetrates into the subfloor space, freely passes up to the ridge and is removed by the tent ridge. If the ridge is no longer than 10 m, through the end.
Ventilation of the sub-floor space of a corrugated roof is ensured by installing ventilation slats on the waterproofing layer. The lowest rail near the eaves should be 50% thicker than the others.
The waterproofing does not reach the roof ridge so that, while ensuring high-quality ventilation of the corrugated roof, it does not prevent the escape of vapors. And the flow of water from the outside is prevented by sealing the ridge with the “top roll” system. You can also install a roof ventilation ridge under corrugated sheeting or metal tiles.
Ventilation of a pitched roof
More often, shed roofs are installed over verandas and terraces where ventilation is not needed. And the situation is completely different when it is above a residential building. Ventilation of a pitched roof is very simple to install and this is a great advantage of the design. There is no need to purchase aerators or install a specially shaped ridge, but only correctly assemble the roof itself.
A pitched roof definitely needs ventilation. Space is left under the roofing material for free movement of air flows. The movement is carried out from bottom to top. Therefore, a gap is left between the thermal insulation layer and the waterproofing. Additional ventilation holes are often drilled into the crank walls.
The roof overhangs are covered with perforated soffits. When installing the sheathing, small gaps are left between the boards. You can also install ventilation grilles. Pedestal roofs with a slope angle of 5 - 20 degrees are ventilated.
Hip roof ventilation
When constructing roof ventilation for a hip structure, they are guided by the principles already stated above. This is a natural ventilation method in which air enters the roof space from under the eaves and exits near the ridge.
Therefore, special attention should be paid to the wind lining of the cornices. If the cornice is hemmed with wood, gaps are left between the boards. It is more convenient to make the lining from ready-made perforated plastic (soffits). If the lining is already ready, but ventilation is not provided, openings are cut into which grilles are installed for supply ventilation of the hip roof. The diameter of the gratings is 5 cm, they are covered with a fine mesh. Gaps of no more than 0.8 meters are left between the gratings. There are models on sale in a variety of colors and shapes.
When constructing private buildings with a small number of floors, it is important to draw up in advance a design of all engineering systems and components that ensure the functionality and durability of the facility. It is imperative to consider where the ventilation outlet to the roof will be located, since without this component the building will not meet regulated sanitary and hygienic requirements.
- 1. In the interior rooms of the cottage.
- 2. In the drain pipe of the sewer riser.
- 3. In the attic.
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General information
If you plan to build a turnkey private house or cottage from scratch, you need to determine the optimal place where you can install a ventilation outlet. This type of natural ventilation does not require the purchase of expensive devices and systems, and there will always be a comfortable microclimate inside the room, enriched with fresh air.
In addition, you can equip the structure with a small fan that operates on the principle of forced exhaust. But if you correctly install the fungus on the roof structure, then you simply won’t have to buy additional devices.
The effectiveness of natural ventilation directly depends on the location of the pipe. Accordingly, the higher the unit is installed, the stronger the thrust in it.
Very often, designers do not draft the installation of risers well enough and select the height above the roof structure. In this regard, various problems may arise in the future. Among them:
If the ventilation pipe is installed incorrectly on the roof structure, the rafters and sheathing may be deformed. Moreover, there will be gaps where the shaft cover is installed, which will increase the risk of rainwater entering the room. Therefore, in order to avoid such consequences and keep the roof in good condition, it is necessary to responsibly approach the issues of arranging ventilation outlets to the roof.
Installation of a ventilation duct in a private house, calculation of the cross-section, diameter and height of the ventilation ducts above the roof
Drafting
You need to begin work on installing a fungus for ventilation on the roof with a preliminary drawing up of the project. It is important to carefully consider the fundamentals of the entire construction, and only after that begin installing the components.
If there is a need to replace the roof as part of the reconstruction, and through the roofing structure it is necessary to remove hoods from all parts of the house, then many may have a question : Is it possible to combine all channels into one? and not separate them into four separate passes?
But experienced experts say that this approach will not do anything good, so it is much more reasonable to arrange a separate ventilation passage for each of the air vents. In this case, the problem with an unpleasant odor in living rooms will simply disappear when weather conditions change.
Purpose and main types
When arranging an exit, you should know about the main subtleties of the upcoming work, understand the types of structures and their purpose. Roof ducts can be used in different types of ventilation systems:
Moreover, sometimes these passages are necessary for laying smoke shafts and television antennas. At the end of the air exhaust system there is a special ventilation outlet, which is equipped taking into account all the requirements for the system.
The purpose of such a design is to ensure effective exhaust of air from the room and prevent any leaks. At those points where it is necessary to make a ventilation passage through the roof, special passage elements are placed that correspond to the specific roofing material.
Currently, it is possible to buy ready-made sets of ventilation outlets for their further installation on roofing structures made of hard and soft materials. Such products allow you to quickly and efficiently build a ventilation riser to protect the roof from possible leaks, as well as maintain its aesthetic appeal. Moreover, such devices are a natural protection of ventilation ducts from the penetration of various dirt and precipitation.
The height and shape of the passages through the roof are determined by the individual characteristics of the roof structure. In addition to pipes with a round cross-section, rectangular structures are used.
To ensure that the ventilation pipe does not lead to a violation of the roof’s tightness, it is necessary to follow a certain sequence of actions and take into account the established requirements.
Node device
If we consider the simplest ventilation outlets on the roof, they are a small metal pipe, which is located in a pre-made hole and fixed with fasteners. The roof penetration itself can be equipped with a locking valve and a ring that collects condensate.
At the bottom of the pipe, an outlet channel is connected using a flange, and on top there is a deflector or a regular protective umbrella. You can also consider an option with insulation, which uses mineral wool.
The modern market offers more advanced types of roof ventilation systems that meet a new level of quality. At the same time, in terms of design features and operating principles, they practically do not differ from traditional solutions, but have a lot of advantages.
Ventilation. Roof outlets and aerators.
Lids from the manufacturer “Vlipe Vent” are in particular demand. The list of advantages of such products includes the following points:
In some circumstances, when the passage element is not included in the kit and is purchased as an additional unit, the type and profile of the roofing covering must be carefully assessed in order to select the optimal unit. A high-quality passage element will be the best solution to ensure design versatility on any type of roof. Such products guarantee maximum stability and tightness of the ventilation outlet.
INSTALLING AN AERATOR FOR ROOF VENTILATION
The task of aerators
It is no secret that during the cold season there is a possibility of condensation forming inside the roof structure. To prevent the penetration of dampness into the room, to avoid the formation of fungal manifestations and mold, it is necessary to properly arrange internal ventilation under the roof.
The roof ventilation device looks very simple: air masses should naturally move in the direction from bottom to top. To supply new portions of fresh air, special openings in the eaves are used, while the flows exit the room through aerators with a lid. They are located in the roof directly at the ridge.
To prevent precipitation from penetrating under the roofing pie, it is necessary to find a suitable type of pipe cover. The best option is a ventilation fungus on the roof, which performs not only a practical function, but also a decorative one. There are a lot of varieties of such structures on the market, so choosing a beautiful and effective fungus for roof ventilation is not difficult.
Guest house, ventilation
Optimal location
Professional builders recommend placing the pipe directly above the riser. In this case, the productivity of the system will be maximum, which is due to the absence of bending of the channel. If it is not possible to make such an installation, for the correct connection of the nodes it will be necessary to use special corrugated adapters.
On a pitched roof made of metal tiles, it is better to install the penetration near the ridge itself. So the long part of the pipe will be under the roof, insulated from external influences. The remaining short element will be able to withstand any wind blows and other processes.
At the installation stage, it is also important to consider the height of the shaft above the roof. An indicator that is too small will negatively affect traction, and one that is too high will be exposed to gusts of wind and quickly deform. In addition, it will have to be additionally secured with guy wires and other fasteners.
According to current construction standards, the optimal height of the shaft above the sloping roof should be no more than 50 centimeters. If the roof is flat, the height indicator is 30 centimeters. When using the roof to create open areas for recreation, the ventilation outlet must rise at least 2 meters.
House ventilation, roof ventilation. VILPE ventilation solutions. how to make ventilation in the house
By following the above guidelines, you can perform high-quality, reliable and durable installation of the ventilation outlet. In this design, it will serve the owner of the premises for a long period of time.
Based on the above, there are practically no difficulties in installing a ventilation duct on the roof. If you draw up the correct project in advance, carry out calculations and study the installation instructions, the future ventilation system will work best. At the same time, the service life of the roof, which has gone through a lot of changes due to the appearance of a new unit, will not be reduced in any way. But for this you need to take the upcoming work responsibly and follow the basic installation rules.