Condensation in the attic: causes and how to eliminate?
The attic serves people very well and successfully, but only in one case - when it is decorated and prepared properly. It is important to combat not only piercing winds and precipitation, but also condensing moisture. It is worth foreseeing such troubles in advance. If a problem occurs during operation, it has to be solved quickly.
Reasons for the appearance
Condensation in the attic appears due to:
- poor quality thermal insulation;
- weakness of thermal protection;
- ignorance by builders of ventilation of the space under the roof;
- non-professional vapor barrier or waterproofing;
- poor installation of slopes and skylights.
General conclusion: liquid condensation begins as a result of deviations from the standard technology. Also, this problem can arise when repairs are made using substandard materials.
When an impermeable film is placed under the roof, it creates excellent conditions for condensation to form.
The immediate savings will result in subsequent significant costs and it is important to know how to fix the problem.
Ventilation
When condensation forms in the attic, work on air exchange is required.
It must be provided constantly and in the entire internal volume.
Having solved this problem, the builders will achieve instant drying of the condensing liquid, it simply will not have time to form drops. But such a measure does not help to radically get rid of the problem, simply because it is a struggle with the consequences, and not with the cause.
It is recommended to invite specialists and carry out a thermal imaging survey of roof structures. You will almost certainly need to re-plan skylights, add insulation, or create additional ventilation ducts.
Important: when the attic sweats, you can safely take care of ventilation, without fear that this will lead to hypothermia of the living rooms. When everything is done correctly, there is no risk of freezing the house.
Cold attic
When a cold attic gets wet, it is exposed to the accumulation of condensation, you need to adjust its ventilation first. Overlapping of rafters and lathing is unacceptable. If you cannot do without this, you will have to form a lining with gaps through which air can circulate freely.
Laying slate and ondulin without films placed under them allows for automatic ventilation, then air flows between parts of the roof can move calmly. But when using metal tiles, the risk of condensation still remains.
Ventilation on a gable roof is placed in the gables, for example, taking care of the loose placement of the overhangs. By arranging narrow slots at the same distance from each other, you can increase the ventilation efficiency. When the pediments are stone, or the resource from the approach of the hole has already been used, additional airflows need to be made.
They are placed either on opposite walls, or simply use conventional ventilation grilles, which are supplemented with mosquito nets.
With a hip roof, this approach will not work. The entrance is prepared at the bottom of the filing, and the air exits at the ridge.When the overhangs are hemmed with wood, it is permissible to put the timber loosely, leaving a gap of 2-4 mm. Special holes are made in the plastic layer, then the panel is called soffit.
Warm attic
Heating systems of a modern level almost exclude natural circulation, therefore, one simply cannot do without enhanced ventilation. Under the flexible tiles and sheet metal, a counter-rail is sutured, providing local ventilation of the area. A windproof film should be used under a metal roof. When slate is located at the top, there is almost no need for counter-racks, since the pie itself does not interfere with circulation.
The air intake is organized through the windows, and its exit through special openings. If they are not there, the hood is equipped with aerators in the form of "fungi".
Tips for the right device
A private house has its own subtleties of arranging the roof, preventing the appearance of condensation:
- you need to bring the holes in the ridges of the roofs closer together as much as possible;
- relies on taking care of the strength of ventilation structures, their ability to resist strong weather influences;
- airflows should be made between the rafters;
- thinking over the device of the holes, you need to make them such as to avoid air pollution or blocking its flow;
- supply units are mounted in the cleanest point of the attic.
Solutions
If the insulation in the attic is wet, it is necessary to change the design so that the dew point is located inside the insulation layer. The layer of mineral wool must be at least 250 mm. If water collects under the vapor barrier, a vapor-permeable membrane must be placed above the insulation.
Roof insulation
The appearance of liquid in the attic may be due precisely to the fact that the protective layer is too thin. Finding a weak spot is easy, even without the help of a thermal imager. When snow falls, it is necessary to inspect its layer, where melting will be noticed, and excessive heat passes there.
Elimination of ventilation deficiencies
So that even the moisture that gets there does not linger in the attic of a wooden house, it is recommended to place the ventilation holes correctly - under the eaves of the roofs and in their ridge. When the air circulation inside is correct and clear, the accumulation of snow and ice on the roof surface is minimized.
Moreover, the well-organized movement of air masses helps to reduce the adhesion of snow to the roof surface.
When using aerators (at the final stage of work), you can give them any shape you want.
Replacement of low-quality heat and waterproofing
When the appearance of condensation becomes a consequence of the use of low-quality materials, you must first change the film of a conventional sample to a membrane layer. This coating reliably allows water to pass out, but does not allow it to get inside.
The surface, which is covered with pile, avoids the formation of drops.
It so happens that these steps do not help. Then you will need to change the crate and vapor barrier material. When the outflow of air is disturbed and its circulation does not occur, dampness accumulates more actively. It will be necessary to equip this part of the room, attracting a trained specialist and creating the required 4 cm ventilation gap.
Dormers and other devices
The provision of dormer windows is not the most effective way to drain an attic. Their minimum allowable size is 600x800 mm. Windows are installed on mutually opposite pediments. The distance to the cornices, the sides of the structure and the ridge is made exactly the same.
The modern solution to the same problem is the aerator, displayed at the highest point of the roof (roof slope). It is customary to distinguish between point and monolithic aeration means. The former have to be supplemented with fans, while the latter are made like a plate placed along the ridge.
Roof repair
When repairing a roof, mineral materials for overlapping must be laid with a layer of at least 20 cm (as recommended by GOST). Some manufacturers indicate that thermal insulation should be made at least 30-35 cm. By observing these rules and checking problem areas with thermal imagers, complete success can be guaranteed.
Tips & Tricks
It is important not to forget about the creation of perforated spotlights near the cornice.
The insulating layer is always placed strictly along the rafters to avoid liquid droplets.
Considering that the cost of creating a good attic is up to 1/5 of all the costs of building a house, it is more practical and economical to do everything at once than to return to work after a while.
When creating ventilation holes, it is worth forming at least 1 sq. m of air passages for 500 sq. m area. This is sufficient to maintain freshness without excessive heat loss.
How to eliminate condensation in the attic, see the following video.
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