Installation of roof ventilation: installation of ventilation outlet and supply units

The problem of lack of fresh air in a private home is usually solved by properly arranging the air exchange system. Thanks to her work, the housing will always have an ideal microclimate for work and leisure.For stable operation of the system, it is necessary to install ventilation on the roof, increasing the draft in the exhaust pipe.

Exhaust air with moisture generated during human activity is disposed of through ventilation outlets on the roof. The speed of air movement through the system largely depends on them. The greater the draft, the more effective the ventilation.

In the article we presented you will find detailed information about the design of ventilation communications exits to the roof. Learn how to install and secure them correctly. Independent home craftsmen will receive valuable recommendations.

Functions of ventilation outlets

In one- and two-story houses, exhaust ducts from the kitchen, bathrooms, showers, swimming pools, technical rooms (laundry, drying room, room in which the boiler is installed) and the basement are led to the roof through the attic or attic.

According to the requirements of the standards, in ventilation it is impossible to combine air ducts leading from the kitchen and bathrooms either with each other or with the chimney into one channel. Therefore, several ventilation pipes and a chimney are usually discharged through the roof of the house.

It is permissible to lay them in separate channels in one ventilation shaft. The air duct from the basement is usually routed along the façade of the building and also has a separate outlet.

In most cases, it is advisable to combine all ventilation outlets and pipes into one duct, since cutting and sealing one large hole for the duct in the roof is easier than several smaller holes for pipes

Correct calculation of the ventilation outlet is the key to good draft. Natural draft is formed due to the difference in pressure of air masses on the street and inside the exhaust pipe. 

It is necessary to take into account the height of the ventilation riser, the correspondence of the diameter of the air ducts inside the house to the length exhaust pipe, its location is on the roof. The higher the ventilation pipe, the stronger the draft will be in it. A ventilation installation on the roof will help increase draft.

To block access to rain, an umbrella is mounted above the outlet of the pipe or duct. This is the simplest type of deflector that works well in areas with high and medium wind loads. When there are gusts of wind, a vacuum is created inside the duct, which greatly enhances the draft.

In natural air exchange systems operating in areas with low wind activity, a turbine deflector is installed at the mouth of the hood. Such a device can increase traction even with a light blow of an almost imperceptible breeze.

In addition to protection from all types of external contaminants, any type of deflector prevents the air flow from overturning due to the lack of draft in the pipe.

The best way to increase traction is to install a turbo deflector. Its head rotates from the wind, due to which the vacuum in the ventilation duct is significantly enhanced

Thus, the following depends on a properly designed ventilation outlet:

• the presence of good draft in the ventilation ducts;
• good air exchange in interior spaces;
• absence of odors in the house;
• reducing humidity levels in wet rooms (bathroom, laundry room, shower).

If the width or height of the ventilation outlet was calculated incorrectly, draft may be lost in the ducts or reverse draft may occur.In this case, in addition to the deflector, it is also advisable to install a check valve that prevents the reverse movement of the exhaust air mass.

Ventilation pipe passage unit

The ventilation pass-through unit on the roof is a pipe made of metal or plastic that is placed in a hole in the roof. The pipe is fixed in a metal cup. After its installation, the hole is sealed and insulated from the outside and inside. An air duct is connected to the unit from below, and a deflector is installed on top.

It is more convenient to use a ready-made factory shaped product to install the ventilation pipe passage. Manufacturers of ventilation systems offer many models that differ in design, shape and color. Each type of roof has its own types of ventilation pipes.

The greatest demand is for galvanized steel pipes wrapped in a layer of polypropylene. At the bottom of such a product there is a seal, and at the top there is a cap with a deflector.

You cannot combine the air duct outlets into one, otherwise, in the event of unfavorable weather conditions, unpleasant odors will spread throughout the house as a result of reverse draft.

Features of installation of the ventilation pipe passage unit depend on a number of factors:

• depending on the type of roof - complex or flat, single- or gable;
• from roofing material - metal or ceramic tiles, corrugated sheets, soft tiles, etc.;
• from the corner of the pitched roof.

Sealing and insulation of the roof at the installation site of the passage element must be carefully carried out. If this is not done, moisture will enter through the junction of the pipe and the coating into the thermal insulation layer of the roofing pie and into the room, which will cause destruction of the structures.

The junction of the ventilation pipe and the roof must be carefully sealed.Sealing is done by applying a water-repellent material to the passage and applying silicone sealant under the ventilation outlet flange

What are the basic requirements for the passage unit:

• the pipe outlets must be strictly vertical so that the air does not encounter obstacles when moving upward;
• for each air duct - from the kitchen hood, from the sewer riser, from the bathrooms - there must be a separate exit to the roof;
• the best option is that the exhaust outlets run close to the ridge edge of the roof, but so that the run is not broken and the entire rafter system resting on it is not weakened;
• the selected shaped products must ensure unhindered movement of air masses and tightness.

The main element of the passage unit is the exit - a shaped product: a pipe with a flexible metal base made in the form of a flange. It is pressed against the roof covering, giving the relief of the roof on which it is mounted. During the installation process, the geometry of the roofing materials used is achieved and an impeccable sealing of the unit is ensured.

On sale you can find different types of shaped products that facilitate and speed up the installation of ventilation outlets on the roof. Can be purchased separately - outlet for exhaust hood, separately - for sewerage, etc.

Roofing penetration: correct installation will ensure complete tightness of the roofing pie

There are several types of pass-through elements:

1. Valveless/with valve. Valveless models are perfect for installing ventilation outlets in a private home. Valve valves are more suitable for industrial buildings.
2. With/without insulation. In cold regions, it is better to choose a ventilation outlet with thermal insulation. Moreover, insulation is necessary if the pipe is placed close to the eaves.In regions with warm winters, an option without insulation will be sufficient.
3. With manual and auto control. The choice depends on the design budget. Products with a cable for regulating air circulation are very popular among owners of private houses.

For ventilation penetration devices You cannot buy a similar part for a chimney, since they have fire protection that is unnecessary for ventilation outlets.

Recommendations for installation and fastening

You can install the ventilation outlet on the roof with your own hands. The installation location of the pipe should be chosen in such a way that, if possible, it passes through the attic without turning. At the same time, it must not cross the rafters, much less the ridge girder.

The best option is when the ventilation pipe outlet is located directly above the internal ventilation shaft riser or air duct. If this is not possible, a corrugated pipe can be used for the connection.

The pipe must be connected to the riser strictly vertically

When placing pipes or an exhaust duct, the minimum permissible distance from the supply air intake must be taken into account:

• horizontally - 10m;
• vertically - at least 6m.

The height of the ventilation pipe is determined as follows:

• if it is located near the ridge, the final opening of the hood should rise above the ridge by half a meter;
• if there is from one and a half to three meters left to the ridge, the hole should be level with it;
• if the pipe is located more than three meters from the ridge, the hole is drawn along the side of an angle of 10 degrees to the horizon with the apex on the roofing ridge;
• if the ventilation outlet is located next to the chimney, the length of the pipes should be the same;
• on a flat roof, the height of the pipe is calculated according to a special table, but it should not be lower than 50cm.

When installing a pipe on a pitched roof, the ventilation outlet should be placed as close as possible to the highest point of the roof - the ridge. In this case, the largest part of the pipe will be located in the attic or attic space and will be protected from strong temperature changes and gusts of wind.

The height of the roof ventilation pipe is selected depending on the distance from the ridge. These conditions must be observed so that the exit does not end up in the backwater zone

For a flat roof, the main role is played by the geometry of the air duct, which should be located directly under the exhaust pipe so that the air can freely flow out into the street.

Ventilation outlet installation

Installation of the ventilation outlet is carried out in accordance with a pre-developed diagram of the location of the outlets. Installation features depend on the type of roof and pipe design. The packaging of shaped products must include installation instructions.

The passage unit must be carefully sealed on all sides. Factory-made products are usually equipped with everything necessary to provide complete protection against water

In general, the installation is carried out according to the same algorithm:

1. At the exit point of the pipe, markings are made corresponding to the diameter of the hole. If the pass-through element comes with a template, the markings are applied according to the template.
2. A hole is cut in the roofing pie with a chisel or metal scissors: in the roofing material, in the layer of waterproofing and insulation.
3. The sealing gasket is secured with liquid sealant.
4. A passage element is placed on the gasket and secured to the roof with self-tapping screws. The base of the walk-through part should be attached to the roof as tightly as possible.
5. An air duct pipe is attached to the passage element and secured with screws.When working, it is advisable to use a plumb line or a building level to fix the pipe vertically.
6. From the attic side, the air duct exit to the roof is sealed.

The ventilation pipe outlet is the most technically vulnerable node in the entire ventilation system in the house. Here it is especially important not only to solve the aesthetic problem, but also to ensure reliable waterproofing of the passage while maintaining its properties for the entire life of the roof.

To increase the draft in the ventilation system, it is necessary to the deflector is put on. A deflector is a nozzle in which air masses become rarefied under the influence of wind. This reduces the aerodynamic resistance to flow.

When choosing a deflector, you need to take into account the climatic characteristics of the region. A number of manufacturers achieve the same goals by equipping the umbrella with an electric fan.

So the deflector acts as a traction amplifier. In addition, the exhaust device:

• protects the ventilation system from precipitation;
• prevents the wind from blowing inside the ventilation pipe;
• prevents the phenomenon of reverse draft.

The operating principle of any type of deflector is based on the rarefaction of the air mass at the mouth ventilation duct, as a result of which the exhaust air moves rapidly in its direction without mechanical impulse.

Types of deflectors for ventilation systems

Today the following types of deflectors are used:

1. TsAGI with diffuser — expansion of the ventilation duct: the most effective design when the wind flow moves more than 2 m/sec. The design consists of a lower glass with an extension at the end, a cylindrical steel body, an umbrella-lid and lid mounting posts.
2. Volper-Grigorovich cylindrical fungus — a nozzle that successfully compensates for pressure loss at the outlet.Consists of a lower glass, an upper glass with concave walls, a conical umbrella and fastenings. Volper's fungus protects the ventilation system from wind better than TsAGI.
3. H-shaped pipe manifold It is an element of pipes in the shape of the letter H. This rather bulky design completely protects against wind, moisture, reverse draft, and freezing. However, the design increases the traction force minimally.
4. weather vane When working, always turn its back side to the wind, which prevents it from blowing inward. A zone of low pressure appears behind the nozzle body and the air stream leaves the vertical channel faster. Effective for increasing traction, but does not protect well from rain.
5. Turbo deflector - This is a spherical rotational deflector with many semicircular blades that rotate with the wind. A vacuum appears inside the ball. Ineffective in calm weather.

One of the improved varieties traditional fungus on the pipe is a static-dynamic device of the Astato type, which consists of 2 truncated cones, whose vertices are turned towards each other. On top there is an electric fan and an umbrella.

The system is effective even in complete calm. The only drawback is the high price.

When choosing a deflector you need to consider:

1. The size of the nozzle must be selected according to the diameter of the hood barrel. If the house has a rectangular shaft, you will have to use an adapter.
2. TsAGI and the Volper deflector do not require maintenance.
3. In the absence of traction, it is better to install dynamic versions of the caps.
4. When purchasing a rotating deflector, you need to choose more expensive models with a sealed bearing that does not freeze in winter.
5. In areas with strong winds it is better to choose an H-shaped deflector or turbo-reflector; for other climatic conditions - TsAGI.

If you have a budget, you can install Astato in any region. The device requires periodic maintenance.

You can assemble the TsAGI deflector with your own hands. It differs slightly from the usual Grigorovich umbrella. The only difference is the shell attached around the fungus

Let's look at how to properly install a ventilation hood on the roof. After purchasing the model, you need to assemble it and securely fix all the fasteners. Then, when mounting the device on the pipe, you need to carefully drill holes for mounting. The device is secured with screws or rivets. Additionally, you can install a clamp.

Features of roof fans

Another element of the ventilation system is a roof fan. With the help of these devices, polluted exhaust air is removed from the premises.

They are mainly designed to work in general ventilation systems without ventilation ducts, but are also used with air ducts. The main advantage of roof fans is that their use allows you to reduce the required length of air ducts.

In regions with low and medium wind loads, you can install an original and effective weather vane deflector. It will make the system work even with slight blows of wind

Options for roofing fans vary in size, power, performance, and sound pressure level.

The following common types can be distinguished:

• axial VKOs are installed on industrial buildings;
• SHELTER can be used in private homes;
• VKRM and VKR are connected to the air ducts.

What are the advantages of roof fans:

• installation does not require a separate room;
• easy maintenance;
• models with hinged housings make access to the main parts easier.

When choosing a roof fan, you need to pay attention to the performance of the model, the material of the housing, the method of power supply, and the noise generated.

If there is no draft in the exhaust duct, a roof fan is a good solution to the problem. When using models with vertical exhaust, air is thrown upward, sometimes up to several meters in height

Most products are manufactured as centrifugal or axial:

1. An axial fan is used to pump low-pressure air masses. When gas moves through the rotor, it does not change direction, moving along the axis of the engine.
2. The centrifugal fan is equipped with special blades that distribute air to the sides, which then moves towards the outlet.

Types of roof fans are divided according to the direction of discharge. Fans with horizontal discharge are installed where the exhaust air is not contaminated and there is no risk of it mixing with fresh air entering the house.

Roof fans can be installed on different types of roofing. The technology for constructing a passage unit in a hard roof is simple. A technological opening is cut in the ceiling, and a brick foundation for the fan is built onto the ventilation shaft.

To simplify installation work, special glasses are used, which are sometimes supplied complete with fans. The glasses have holes on the mounting flanges and are attached to the roof with anchor bolts. The fan and the glass are connected by bolted flanges.

There should be a rubber gasket between the flanges for greater tightness. During installation, the glass must be positioned strictly vertically. The fan on the glass is mounted horizontally. After installation, possible gaps are eliminated with sealant. Then the steel apron is installed.

Conclusions and useful video on the topic

Large manufacturers of ventilation systems produce video instructions for installing on the roof and fastening supply and exhaust units, shaped elements, aerators, and deflectors:

Arrangement of the exit through the roof to the roof of the ventilation pipe of the house must be approached especially carefully. Indeed, in natural ventilation systems, the presence of draft in the system depends on the state of this unit.

Do not allow the pipe to become flooded with rain or ice. Therefore, much attention is paid to sealing the assembly itself and installing additional protective parts. The installation of air supply devices is carried out in the same way.