Proper ventilation creates comfort and maintains a healthy microclimate in residential, public and industrial buildings. Insulation of ventilation pipes in a cold attic is one of the measures to ensure the operability of air removal systems. The work is easy to do on your own if you follow the simple rules.
The need for thermal insulation
Without insulation, ventilation in the attic in the cold season, condensation falls on the inner surface of the pipes. The reason for its appearance lies in the laws of physics. The relative humidity at room temperature is normally 25 - 40%. In absolute terms, a cubic meter contains up to 10 grams. water.
Rising along the non-insulated ventilation duct to the roof, the air is cooled. At a temperature of -10 aboutWith moisture content cannot exceed 1.5 g / m3... All "excess" water from a vaporous state passes into a liquid form. Condensation is formed, which drops out in the form of drops on the inner surfaces of the mines.
The appearance of condensation in pipes entails unpleasant consequences:
- Freezing, the water forms an ice crust in the pipes, the inner lumen decreases. The draft deteriorates, the air exchange in the room decreases.
- Metal channels are destroyed by corrosion.
- In brick air ducts, moisture seeps into the cavity of the structure, where it freezes and expands. The brick gradually collapses.
- Under the ceiling, above the ventilation grilles, where air flows are minimal, colonies of fungus and mold form and develop. Microorganisms spoil the finish and cause allergic reactions in people.
The lower the outside temperature, the more condensation will form. Therefore, the insulation of the chimney is an important stage of construction.
Characteristics and use of materials
Materials of different structures are suitable for insulating ventilation ducts in a cold attic.
Insulation selection criteria:
- terrain-suitable thermal conductivity;
- Fire safety;
- sound insulating properties;
- cost;
- manufacturability (simplicity) of installation on various pipelines;
- life time;
- resistance to mold and mildew, unsuitable for rodents:
- mechanical strength in the absence of external finishing.
The colder the region, the lower the thermal conductivity should be. As an option - the choice of thick insulation.
Fire safety is important if ventilation mines pass near chimneys that are heated to high temperatures.
During construction, every ruble is saved, so the insulation should be chosen according to the price / quality ratio.
Manufacturability implies a short installation time using the minimum set of tools available in any household.
Soundproofing ventilation ducts is important for tall buildings and in areas with strong winds. Under certain weather conditions, the pipes emit an unpleasant howl, so it is advisable to close them with insulation along the entire length, and not only in the attic.
Mineral wool
The concept of mineral wool means several types of materials made from different raw materials. Finished products are distinguished by their consumer properties and price.
Comparison of the characteristics of different types of mineral wool.
| Characteristic | Slag | Glass wool | Basalt wool |
| Thermal conductivity, W / (m2*TO) | 0,45 – 0,48 | 0,04 – 0,046 | 0,035 – 0,042 |
| Operating temperature range, оС | -60 – 240 | -60 – 450 | -180 – 600 |
| Fire resistance | non-combustible | ||
| Moisture absorption,% per day | up to 2 | ≤ 1,9 | ≤ 1,7 |
| Release form | rolls |
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In damp rooms, it absorbs a large amount of moisture, quickly cakes and loses the quality of insulation.
Glass wool are made from the battle and marriage of glass-container factories. Having good insulation properties, the material requires compliance with safety measures during installation.
Glass particles irritate the skin, mucous membranes of the eyes and respiratory system. When installing, be sure to use protective equipment for eyes, breathing, work in gloves and closed clothing.
The material is not resistant to mechanical damage and requires an outer layer of protection.
Installation on vertical surfaces ensures thorough attachment to the base, since the cotton wool loses its shape as it is used.
Average replacement time is about 10 years.
Stone (basalt) wool is produced from rocks with a small addition of chemical additives. Environmentally friendly product is easy to install due to its dense structure.
The process of thermal insulation using any type of cotton wool is costly, since the installation of an outer layer of protection is required.
Algorithm of insulation in roll version:
- The material is wrapped around the pipe without gaps or voids. Fastened for convenience with a thin soft wire.
- A layer of thick foil or galvanized metal is mounted around the cotton wool.
- Tighten the structure with steel clamps.
The slabs are attached to the brick surface with dowels with wide caps or with a special cement-based glue.
The material must be protected from moisture.
Basalt wool with a density of 50 kg / m3 can be plastered with cement compounds. After installation, an adhesive composition is applied to the surface of the slab and the plaster mesh is pressed into it. After complete drying, they are finished with a cement-sand mixture, which can be subsequently painted.
Polyethylene foam
Varieties of material are sold under the names: penolon, isolon, tepoflex, etc.
Thermal conductivity 0.045 - 0.055 W / (m2*TO). Polyethylene foam practically does not absorb moisture, the service life is about 25 years.
Working with the material is very simple - the sheet is wrapped around the pipe and fixed with tape. It is important to accurately carry out preliminary measurements so that there are no unprotected places left - cold bridges.
There is foil-clad isolon on the building materials market. Due to the metal layer, the sheet reflects up to 95 - 98% of the heat, which improves the insulation performance. These sheets are fixed with aluminum tape or special glue.
Polyethylene foam belongs to a moderately combustible class and emits harmful substances during combustion - it is not recommended to use it near hot chimneys.
For smooth plastic or metal pipes, they purchase an adhesive-based material, which makes installation easier - just remove the protective film and stick a sheet of insulation.
Expanded polystyrene
- foamed, it is often called polystyrene;
- extruded, some manufacturers call extrusion - expanded polystyrene, Penoplex, Technoplex.
Advantages of expanded polystyrene:
- low price;
- stability of characteristics at different temperatures;
- does not get wet and does not change properties under any operating conditions;
- self-extinguishing time after cessation of exposure to open flame - 4 sec.
When heated, the material quickly collapses, emitting harmful substances, therefore, it is unsuitable for places where chimney shafts pass.
The thermal conductivity of both types is the same - 0.032 - 0.05 W / (m2* K) and depends on the density. Working temperature from - 50 to 65 aboutFROM.
The density and price of polystyrene is higher than that of polystyrene.
The structure of extruded polystyrene is harder and more convenient to use in work.
Insulation of ventilation pipes will save you from rework in the next 50 years.
The process includes several operations:
- Sheets of polystyrene (polystyrene) around the perimeter are attached to the brick chimney with dowels. They are glued to metal channels with mounting glue.
- Free cavities in the corners are filled with some kind of heat-insulating material, foam chips.
- The joints are sealed with polyurethane foam.
- Cover the material with finishing - metal, siding, etc.
For round pipes, molded parts of different diameters are produced. At the joints, a thorn-groove connection is used, which simplifies installation, eliminates the occurrence of cold bridges. This method has one drawback - parts are released only to cover straight sections. The turns will have to be insulated in a different way.
Synthetic rubber
In terms of structure and characteristics, rubber is close to polyethylene. It is produced in the form of sheets, rolls, cylinders. The closed pores of the material make it completely moisture-repellent. Thermal conductivity 0.024 - 0.038 W / (m2*TO). At temperatures from -200 to 180 aboutS retains all qualities.
The joints are sealed with special glue or tape.
Factory solutions
In some cases, it is more convenient to use industrial finished products.
The section of the insulated ventilation duct can be assembled from ready-made sandwich pipes. The structure consists of two layers of steel between which a basalt wool insulation is laid. Elements are unified in size (diameter and length).
During assembly, individual parts are simply inserted into each other.
Most of the products are made of stainless steel, so the service life is 15 years or more.
Do-it-yourself work on the hood insulation in a private house will not take much time. The costs are low compared to the consequences of inadequate ventilation. The correct choice of materials and installation will make the ventilation operation trouble-free for the entire period of operation.
