The roof and attic are designed to protect from wind, cold and dampness. Sometimes they themselves become a source of inconvenience: not only do they not interfere with the penetration of moisture, but are also abundantly saturated with it. Without solving this problem, it is difficult to count on the comfort in the house and its durability.
Causes of occurrence
The physical essence of the phenomenon is quite simple: condensation always appears when cold and heated air meet each other. Only by reliably separating them and not allowing them to enter into "close contact of a wet kind", you can achieve perfect dryness. Experienced builders know how to achieve this, so it is not worth saving on their services.
The technical reasons why dew forms in the attic are as follows:
- poor quality of roof insulation;
- weakness of thermal protection;
- lack of ventilation under the roof itself;
- mistakes when laying protection against steam or water;
- poor installation of windows, slopes and roof doors.
What they have in common is that all these are the consequences of technological errors, flaws or improper savings on materials. Trying to save money in this way is a serious blunder, since eliminating the condensation that has appeared is much more difficult than avoiding its occurrence. A cheap film seems to perform the task of waterproofing, but the surface impermeable to steam will prevent condensate from volatilizing. He can only fill in the insulation or seep onto the surface of the finishing material.
How to remove?
Not all builders perform their tasks efficiently, and DIYers often make mistakes. In addition, the finishing "pie" can deteriorate over time: it is damaged by careless repairs and improper use. Finally, a house with condensation in the attic may come from the previous owners, and this problem must be solved.
First of all, if condensation collects in the attic, you need to study the air movement properly. Normally, it should be continuous and cover the entire volume of the room.
A professional with a thermal imager should inspect the attic, his consultation will allow you to detect all deviations from the norm. When the picture is clear, you need to check with the roof formation diagram. Most likely you will need:
- change the location of the attic window;
- strengthen the insulation layer;
- make additional ventilation openings.
If it is known that the attic space is getting wet due to the use of low-quality materials, the problematic design will have to be changed. The best replacement would be a membrane layer that will not allow condensation to form: water quietly comes out, but does not penetrate inside, and the layer covered with pile prevents drops from forming on the surface. It so happens that even after replacing the waterproofing, the attic in a private house sweats. Then there is nothing left but to adjust the crate and the vapor barrier layer. After all, they can also interfere with the normal course of air masses, provoke the accumulation of dampness.
You should not take drastic steps on your own - it would be much more correct to invite an experienced installer. It will not be possible to get rid of condensation of water vapor until the standard 4 cm ventilation interval is provided.
When the perforated soffits on the cornice are correctly prepared, when the insulating layer is laid on the rafters themselves and under the crate of the metal tile, then the insulation will not dampen.There is a popular myth that ventilation leads to heat loss in the attic during the winter months. In fact, the situation is different: pExcessive cooling is caused by poor thermal insulation.
When it is done poorly, the dew point is inside the roofing "pie" or on its surface. Therefore, moisture is deposited continuously, and the floors begin to rot.
Airing the attic space is also necessary during the colder months, because otherwise icicles appear inside, then fungi and mold form. It is imperative to make holes of a certain size for the passage of air. Overly small openings have almost zero efficiency. According to experts, 500 sq. m. of the total area, you need to form 1 m2 of ventilation holes. This proportion at the same time allows:
- guarantee fresh air;
- get rid of condensing moisture;
- prevent hypothermia of a cold attic or attic.
Fighting dampness under an unheated wooden roof has its own characteristics. It is unacceptable to close the rafters, as well as the crate. If they are sewn up, then it is required to provide gaps that maintain air circulation. Under the sheets of slate or ondulin, laid without vapor barrier and wind insulation, additional ventilation work is not necessary: the air flow moves freely through the roofing waves.
The placement of ventilation ducts inside the gables will help to increase the efficiency of ventilation of gable roofs. When using stone fronts or the impossibility of abandoning the tight fit of materials, it is required to prepare holes in the walls (at least 0.2% of the total floor area).
Elimination of dampness is possible with the help of more economical materials, that is, using a standard lattice: one instance of it turns with holes downward, the other needs to be periodically adjusted. The mosquito net becomes a reliable barrier against the penetration of various harmful insects.
It is also possible to avoid the appearance of wet areas under the hip roof, but a different technological method is used for this. The fresh air inlet is located at the bottom of the filing and should exit near the ridge. Overhangs, hemmed of wood, are formed from a loosely placed bar, which separates the gaps in fractions of a centimeter. Plastic linings are equipped with air inlets.
The holes in the roof ridge should be brought closer together as much as possible. Often, under the eaves, continuous soffits are placed, which are equipped with a thin mesh screen. The cells of such networks must be plastic or aluminum, otherwise there is a great risk of corrosion. It is advisable to equip the gaps between the rafters with air vents, and the holes are arranged so that there is no air pollution and its movement is not complicated.
The second (but not most important!) Element of condensation prevention is the installation of an exhaust fan on the outside of the roof. It is recommended to distance it from the supply system by at least 8 m.
The installation of a recuperator helps to prevent moisture condensation in attics: it is capable of both cooling and heating the air. It is not only the roof that needs to be taken care of, it is just as important to ensure that the entrance hatch is airtight.
If it is not tight enough, mixing the atmosphere with different temperatures will still cause the beams, floor and other elements to get wet. The problem is solved either by arranging a hermetically insulated cabin with a door, or by preparing a box with a horizontally opening lid and a layer of thermal protection.
No amount of effort will help if the attic is littered with debris and waste, crammed with furniture and foreign objects. After all, even freely entering the air should circulate easily!
For information on how to eliminate condensation in the attic, see the next video.