How to make ventilation in the cellar of a private house

Cellar ventilation is essential. In a residential semi-basement or workshop, it should be more intense than on the main floors — after all, there are no wide windows in the basement. The lack of normal air exchange in the back room, where chemically active substances are stored, will lead to the accumulation of their fumes. At a significant concentration in the atmosphere, they become dangerous. Detergents, fuel supplies, oil paint, acetone thinner can cause poisoning. Cylinders with gas and cans of gasoline in the absence of a fresh inflow for a long time can explode from a spark or a match lit in the room. Ventilation will be needed if the underground is equipped for food storage. Without it, they will be saturated with the smell of dampness and sewer pipes — the interchanges of communications are located at the bottom of the house. Moisture must be constantly removed, otherwise it will settle on the walls, floor and ceiling, gradually destroying the finish. To solve the problem, an exhaust system is needed. Work can be done by hand.

We make ventilation in the cellar of a private house

Natural and forced circulation
How to design a circuit correctly
Features of a one-pipe system
Instructions for installing two-pipe ventilation

• Calculation of working sections
• Form and material of communications
• Installing an exhaust duct
• Inlet valve installation

Natural and forced circulation system

The flow movement inside the building is due to the pressure difference inside and outside the building. In hot weather, it is not significant. In winter, the gas is more rarefied. The higher the altitude, the lower its pressure. It is higher in a warm room. The heated gas expands. Its molecules begin to move more actively, hitting each other. Their speed and temperature are interrelated. If you hold a high pipe to the roof, active gas exchange will begin. It occurs on the principle of communicating vessels — the flow rushes to where the pressure is lower.

In the summer the stream stops. In living rooms located on the main floors, it is driven by the force of the wind. Circulation occurs due to wide open windows. Below, they are completely absent, or their area is not large. Natural ventilation in such conditions is impossible. The only way out is the arrangement of forced ventilation in the basement. The change in air volume is provided by an electric fan powered by a 220-volt outlet. Even such a scheme will not work if you do not create a constant influx. In order for the equipment not to idle, a new volume must be supplied to the place of the removed volume.

How to design a system in a private house

It is better to engage in designing at the construction stage, when it is possible to conveniently arrange prefabricated elements, having determined a place for them in a technical cabinet. The exit is located on the side opposite from the windows, if any. In their absence, install the inlet on the wall or ceiling. A hole under it is drilled during the construction of the basement. Drilling a hole is not necessary. It can be left in the clutch. In the formwork, a hollow part of the desired shape is fixed with the correct dimensions corresponding to the parameters of the valve. When the solution sets, this part is removed or left if it does not interfere with further installation.

In case of deepening of the structure, the branch pipe is fixed in the wall and taken up through the soil. If the ceiling level is above zero, the hole is simply closed with a grate. It protects the body from the penetration of rodents and large insects. With this arrangement, the average height of the snow cover should be taken into account. Snow should not cover the grate, otherwise the basement ventilation in a private house will stop working.

What affects the efficiency of ventilation

• Sections of inlet and outlet channels. They are taken the same in order to create a uniform withdrawal and receipt. It makes sense to design different sections only in the case of constant use of air handling units. The extraction is already done. Please note that when the equipment is turned off, a small amount of gas will be discharged. To prevent the blades from blocking the outlet in the off state, it is better to use a model with a rotary mechanism. It is hinged and able to rotate like a door leaf.
• The volume of the room and its natural microclimate.
• The purpose of the cellar and the required parameters. To store food, you need a temperature of about 5-10 degrees. If it is planned to arrange a bedroom, an office or a workshop in the basement, the conditions should be made more comfortable. They are affected not only by heating, but also by the amount of cold air from the street. The larger the valve section, the colder it will become inside during frost.
• The temperature inside and outside or the power of the supply equipment.
• The height of the pipe and its location. Thrust depends on the level above the zero mark. It is better to bring the hood to the roof through the interior. So on the walls will not accumulate condensate that falls from the cold. One option is insulated outer boxes. The upper part is placed above the ridge or at a considerable distance from it. If the basement stands separately, the hood is raised 1.5 m above the highest point of the roof. Turns create obstacles to the air and slow down its flow. It is better to make it straight in all areas.
• Proper placement of entry and exit. They cannot be placed side by side. The line between them should run throughout the room. There are «dead zones» outside the line. There is no movement in them. Fresh flow does not enter there, and the old damp-soaked volume remains in place. In order for the draft to push it out, this volume must be in its path.

Features of cellar ventilation with one pipe

This scheme is suitable for rooms up to 15 m². Usually it includes only the hood. Most often, PVC sewer fittings with a diameter of 10-15 cm are used. The flow through it is very weak. It is not enough for effective ventilation and maintaining the microclimate with the given parameters. To solve the problem, you can install a mortise valve on the door. It is equipped with a damper and a housing protected by a heat-insulating gasket. Outside and inside it is closed by a lattice.

Air exchange occurs intensively if there are windows under the ceiling. In this case, instead of the hood, a side entrance is mounted, through which air enters from the street. Its output is located at a distance of 10-15 cm from the level of the final floor finish. It should be on the side opposite the transom. Rising when heated, the flow will pass through the entire room, pushing the volume of exhaust gas out the window.

Installation of a system with two pipes

Channel section calculation

This parameter is the most important in natural circulation, as well as in the case of forced supply. If the radius is too large, drafts will begin inside. To raise the temperature, you will need to increase heating costs. Too narrow design will not be able to provide sufficient air exchange. The rooms on the ground floor will be stuffy and damp. Condensation and mold will appear on the walls and ceiling. Dampness has a bad effect on the equipment that is installed in the cellar, its parts wear out faster. There may be a short circuit in the wiring. If there is a boiler room on the basement floor, the temperature may exceed the standard values.

The cross section of the inlet and outlet is capable of providing intensive circulation, but this parameter is not enough to maintain the required microclimate. Temperature and humidity depend on more than just proper ventilation. You may need air conditioning units that humidify the atmosphere, cool and heat it.

The larger the floor area and the height of the walls, the wider the inlet and outlet. With a significant volume, two channels are mounted. To make proper ventilation in the cellar, their diameter must be calculated. According to technical standards for 1 m² for floor heights up to 2.2 m, an inlet and outlet with a cross section of 26 cm is required².

Assume the floor area is 3 x 4 = 12 cm². Ceilings — 2 m. Required section: 12 x 26 = 312 cm². Let’s find its radius: R = √S / π = √312 / 3.14 = 9.97 cm.

The diameter is rounded up to 20 cm. You can use two pipes of 10 cm each.

Form and materials of communications

The shape can be rectangular or round. Rectangular communications do not leave gaps with the plane of the wall and the corner. They are more compact but less efficient. The flow passes better on round walls.

Material options

The material is asbestos cement, metal and plastic.

• Asbestos cement is not durable. He’s heavier. In addition, prolonged contact with this material is harmful to health. This solution is better suited for laying underground utilities.
• Metal is not much stronger than plastic. Products are produced with a protective zinc coating, and after damage they quickly rust. Steel creates vibration noise. They amplify the sound of the fan on and need soundproofing.
• PVC — does not rust, does not resonate and does not need additional protection. Products do not differ in strength from their counterparts. They are easy to cut and install. The only drawback is the low melting point. At 75 degrees under pressure, the material begins to deform.

How to install an exhaust structure

Sewer fittings with a diameter of 11 cm are often used. The standard length is 0.5; one; 2; four; 6 m. Each part has a socket at one end. The smooth side of the next element is inserted into it. The connection is tightened with a metal clamp and fixed with a screw. There are special ventilation pipes with fasteners and adapters.

Design is carried out at the construction stage of the building. To understand how to properly ventilate the cellar of an already built house, you need to study its plan. Before starting work, it is necessary to draw up a diagram, indicating on it the location of all important nodes and their dimensions. You can place the channels in a common riser — so they will not occupy the space of living rooms and other premises on the main floors. They are placed in utility rooms away from the residential area, but sometimes you have to make turns that reduce throughput. To smooth out right angles, instead of one 90-degree adapter, they put two 45-degree adapters. They take up a lot of space, but in a pantry or dressing room this does not matter much.

It is better to drill holes in walls and ceilings with a diamond crown — it leaves even edges that do not need to be strengthened with cement mortar. A hole is made on the ceiling or in the upper part of the wall on the opposite side from the inlet valve. They put a pipe in it. In vertical sections, the pipe is attached to the wall with clamps on self-tapping screws, and special suspensions are placed on horizontal sections. They are thin cables mounted on the ceiling. Plots laid in an unheated attic are insulated — otherwise condensation will form inside. The holes through which communications pass are filled with mounting foam. Its excess is cut off with a sharp knife and covered with a trim.

If there is a reserve for the throughput of a common hood coming from all floors, you can make a cut into it. In this case, you do not have to carry out roofing work. At low throughput, a separate channel is brought to the roof. It is placed above the ridge at the maximum distance from the walls and slopes that create a barrier to the flow. The roofing part is attached to the flange and sealed. The top is covered with a visor so that rainwater does not penetrate inside. The deflector helps improve traction. It creates a vacuum on the leeward side.

If you make an exit near the chimney, the system will work harder. Gas heated by fireplace smoke rises faster.

Supply devices are selected according to the performance indicated on the package.

Inlet valve installation

It should be on the side opposite the hood. It is laid in the wall and released at the bottom at a distance of 10-15 cm from the floor.

The entrance is placed in the basement floor structure or underground communications are being laid. The second option is suitable for buildings under construction.

Communications must be wrapped with geotextiles that protect against freezing and condensation. It is more convenient to use ready-made basement deflectors.

The disadvantage of underground channels is their unreliability. They are laid in dry soils with low mobility, otherwise communications will experience constant deformation.

The top of the buried pipe and the wall valve should be located above the snow level. This indicator is taken from the table in SNiP.

Reinforcement, if necessary, is allowed through the ceiling. If the cellar ceiling is located above the zero level, this is not necessary. It is hidden in a box or under the trim. The entrance and exit are closed with bars.

Inlet devices must have adjustable dampers. Without them, it will be difficult to maintain the required temperature.