The neighbor began to insulate the walls of the house from the inside and came for advice, I had to explain to him why this should not be done.

It's no secret that rather large heat losses in a heated room occuracross outdoor walls.

Therefore, they usually try to warm them.

But they don't always do it right.

So my neighbor decided to do wall insulation in his house.

Not really understanding the process technology, he was firmly convinced, what it is best to insulate the walls from the inside.

Here are the arguments in favor of this method of insulation:

• Profitability. To insulate the walls from the inside, much less material is required than for the entire facade of the house.
• Ease of installation. To insulate the facade of the house, you need to install scaffolding, and in the house you can do with a stepladder.
• Seasonality. You can also do wall insulation from the inside in winter.

And so, fascinated by the process of wall insulation, he came to me to find out whether it will be enough to mount sheets of expanded polystyrene in one layer.

I could not help but share my experience.

More than once I had to deal with the consequences of such insulation.

And they were always almost the same:

• high humidity in the room;
• permanent condensation on the windows;
• and, of course, the walls covered with mold.

Moreover, practically didn't matter, what kind of insulation was used (mineral wool, expanded polystyrene, etc.).

The result was almost the same.

And that's why.

When insulating walls from the inside dew point shifts (border of heat and cold) inside the house at the joint between the insulation and the load-bearing wall.

therefore at negative temperatures, the entire wall freezes up to the insulation, and during a thaw condensation forms at the junction.

As a result wall under the insulating layer starts to get wet, which leads to its faster destruction.

A insulation is saturated with moisture, ceases to perform its functions, and even serves as a favorable environment for the development of mold.

My story, of course, upset the neighbor. But I think it's better to stop on time than to deal with mold in the house later.