Opinion layman familiar with the physics of modern thermal insulation of buildings

Passing by the construction of private homes, I often see the builders produce warming of houses, recently built of aerated concrete. Of course, the most effective thermal insulation should be carried out. But I am always amazed at the ease with which future tenants entrust their health in such a hack.

And the thing is that the negligent builders insulated walls extruded polystyrene. This material teploeffektiven, the work is faster. But polystyrene hardly breathable. It would seem that it is right - who needs a house the cold air in the winter?

In fact, everything is different. Air has such a characteristic as partial pressure. And it is the stronger, the more water vapor contained in the air. In the warm vapor is always more. At a temperature of + 25 ° C in air saturated state includes five times more steam than at 0 ° C. Accordingly, the hot air pressure is greater.

But what happens in the winter. Warm steam presses from inside the building toward the street and the air permeates through the wall being cooled and gradually lose part of the moisture. Therefore, from the street through a heater cold air can not penetrate, even if he will be permeable for him.

What happens if the outside wall is impermeable to the vapor layer of insulation? It's simple - the steam remains in the array of aerated concrete. Over time, fungus and mold can occur due to constant moisture.

Therefore, the need to insulate the walls of a material having a higher water vapor permeability than the water vapor permeability of the wall material to moist air out through the insulation to the outside. This may be mineral wool, cellulose.

If all the same to produce polystyrene foam insulation from the outside, it is necessary to arrange the inside wall of a continuous vapor barrier over the entire area to the water vapor does not penetrate into the material of the walls. A start external insulation only when the masonry of aerated concrete dries completely. Under natural conditions, this process takes at least six months at a relative air humidity of 30-40% on the street.

Of course, the contractor is unprofitable to lose half a year at the facility, so the insulation begin immediately after laying. Thermal insulation of expanded polystyrene is much easier to implement than the mineral wool - no need frame, sheets only glue is attached to the wall. And this is another mistake. In addition to the need to strengthen the adhesive sheets using special fasteners.

If I was building a house of aerated concrete for myself, I would certainly insulate the walls, but for that I would have used the mineral wool insulation.

What do you think about this? Is it worth it for the sake of cost and speed of construction sacrifice their health, then living in a house with Waterlogging air?

p.s .:Subscribeper channelMy house- all the most important, useful, interesting is yet to come!Everyone can share their experience in the construction, repair and improvement of housing, suburban area, send photos, tell me about your country, house, apartment.

See also:

Reconstruction and repair of village house built in the early 20th century. Giving the modern form

dream home, or how not to lose two million