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Sealing your house with air

The airtightness of the house is crucial for its good insulation and for controlled energy consumption. At the heart of thermal regulations, the airtightness of a building guarantees its ability to minimize heat loss between inside and outside, via its envelope. To control the airtightness of the house, it is necessary to reduce the heat loss by treating the general insulation of the envelope and its various thermal bridges.

Airtightness: stakes and principles

When a house is insufficiently airtight, there are many inconveniences:

  • Air Currents,
  • spends a lot of energy to heat the house (and therefore, energy bill accordingly),
  • indoor air of lower quality (the pollution penetrates inside),
  • defective sound insulation (the air is the first driver of his),
  • lower energy performance of the House.

The control of the airtightness of the house is done:

  • at the level of all the walls and the roof,
  • at the junction between the walls and the exterior joinery (doors, windows, shutter boxes, connection between wall and bay, etc.),
  • at the junction between the different walls (at the angles, therefore, especially between walls and crawlers),
  • at the level of all thermal bridgesthat is to say at all places where the wall and its insulation are interrupted (where pipes and ducts pass, at the level of the ventilation duct or chimney, hatches, etc.).

Thermal bridges can be responsible for 25% of heat loss in a construction. Their treatment is therefore essential for a good airtightness.
It may be useful to use the professionals of a thermal design office to accurately detect the areas of leakage and their origin. Small tools make it possible to reproduce at a lower cost the techniques of the professionals, such as the "smoke-pen"(or his cousins, the" smoke-matches "or the" smoke-bottle "), a small" pen "that projects slow smoke odorless (and non-toxic) to allow the identification of air movements and therefore the source of the infiltrations.

Improve the air insulation of your home as part of energy renovation work

During energy renovation work, the treatment of the airtightness of the house is obviously central. It is possible to operate in different parts of the house the materials and solutions adapted to each specific point.

At the level of the peripheral walls
To treat the airtightness of the house by the peripheral walls, one can proceed by ITE (External Thermal Insulation) or by ITI (Thermal Insulation by the Interior)
ITE is heavier but is sometimes more strategic when the defects of the insulation are too important. The existing insulation will be removed in favor of a new, more efficient insulation. This will be the opportunity to correct all the air leaks and thermal bridges of the building.
In ITI (less expensive than the ITE, it is also more limited in its means and its fields of action), there are various solutions to improve the insulation in the air of the house (in complement of the existing insulation):

  • correction of air leaks by caulking the infiltrations at the junctions of the joinery, catches, hatches and siding using insulated joints,
  • installation of independent vapor barrier membranes (These must be laid in such a way that they will not be punctured later, which would create new thermal bridges),
  • projection of an insulating wet compound on the masonry wall.

At the windows
To improve the airtightness of the house at windows and joinery (door, roller shutter box, bay) you can:

  • change the windows for double or triple glazing,
  • treat thermal breakages using insulating joints or putty to ensure continuity with the vapor barrier and / or the membrane.

At the level of the roof
Theroof insulation is one of the main poles of heat loss related to airtightness (up to 30%). The treatment of roof spaces lost and roofing by ITE should therefore be a priority. It is one of the most cost-effective insulation and thermal renovation actions.
This insulation is done by the implementation of an under-roofing film (in combination with a vapor barrier, to limit the condensation) in addition to the main insulation solution (mineral wool in bulk, in roll or blown or polyurethane or polystyrene panels) and especially a membrane that can replace the vapor barrier.

At the floor level
For floors that overlook a cellar or basement, it is possible to implement insulation from the ceiling of the room below and from reduce the thermal bridge of the floor by the ITE of the basement or the crawl space.

Improve the air insulation of your home without major renovations

While thermal renovation works are ideal, it is still possible to treat some of the house's air leaks by paying particular attention to certain elements and treating them with the appropriate materials.
With caulking, caulking, resilient foam or additional membrane pieces secured with a suitable adhesive tape, leaks can be minimized at these locations:

  • shutter boxes (using an acrylic sealant seal),
  • recessed spots in the ceiling under uninsulated attic,
  • around the power supply board (using a complementary piece of membrane perfectly fixed with the appropriate adhesive tape or with insulating adhesive grommets to be placed around the duct exits / entries),
  • at the thresholds of the door thanks to a broom seal,
  • at the level of the trap doors and access through the installation of an adhesive seal.

How to improve the airtightness of a house?: insulation

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