Why the front door sweats - causes and remedies

09-03-2018

Doors

Condensate on the front metal door - one of the main problems of the owners of country houses. Why the door is sweating and how to avoid this trouble, let's try to figure it out together.

If the metal door is installed in a city apartment, its residents may not even suspect the existence of such a problem as condensation on it.

But it is worthwhile to put the same door as an outdoor door in a private house, as it begins to behave completely differently: in cold weather it blows cold, and droplets of water appear on the inner surface, which, with insufficient tightness, turn into frost. If you, when ordering (see How to choose an entrance metal door) paid attention only to its anti-burglary qualities, but did not think about the features of its operation in the harsh conditions of our climate, then you won’t be surprised why it sweats.

Why it happens

Serious manufacturers always care about their insulation and the absence of gaps between the canvas and the box. But these measures do not yet guarantee that no condensate will form on the door.

The fact is that the metal has a very high thermal conductivity, which is almost three hundred times higher than the thermal conductivity of wood.

And even if you fill the cavity between the outer and inner lining of insulation, there are many details in the design that will conduct the cold - the so-called cold bridges.

These include:

Box
Frame stiffeners
Castle

It is precisely because the cold freely sneaks to the inner side of these bridges that it sweats. The air around it cools and cannot hold the moisture contained in it. She and falls to the surface in the form of dew drops.

Moreover, moisture can condense both on metal surfaces and on the slopes around the opening. Especially if the canvas is not tightly sealed to the box.

In this case, the temperature on the inner surface may drop below 0 degrees, and frost will form on it.

How to solve a problem

So that after installation you don’t wrestle with why the door is sweating and what to do with it, it is advisable to provide some nuances while designing the house.

So:

As you know, condensate on it is formed due to the large difference in temperature outside and inside the room. So, it is necessary to exclude this factor by equipping the unheated entrance vestibule.
The device of a visor or a canopy over the door will also in some way help to avoid such problems, since direct sunlight will not affect the outer surface of the canvas and precipitation will fall.
It is desirable that the metal sheet was coated with special powder polymers with weatherproof treatment.
The finishing of the canvas from the outside with decorative panels impregnated with a special weather-resistant composition will not be superfluous.
To avoid the appearance of cold bridges, all hollow metal structural elements can be filled with mounting foam.

Not heated vestibule is made in the case when metal is put first at the entrance from the street, and wooden, plastic and any other at the entrance to the living area.

In this case, condensate is not formed, since the temperature difference outside and inside the vestibule is not large. In addition, the second door cuts off damp metallic air from the house.

Attention! If you decide to put a steel door directly at the entrance to the house, and equip the vestibule with an ordinary door that is not responsible for resistance to breaking, then the temperature in the vestibule should be such that it exceeds the dew point. To do this, it is enough to put a fan heater there that will warm the air and make it circulate.

And in fact, and in another case, they must be sealed - supplied around the perimeter of the seal. A tambour is the most efficient, but not the only way to get rid of condensate. If the house is already built and there is no possibility to make a vestibule, you can insulate the entrance metal door with foam plastic from the outside, and then finish it with weather-resistant decorative materials.

The space between the box and the walls must be filled with foam. And if the box is a shaped hollow tube, then holes are drilled in several places in it, through which assembly foam is also pumped, which is an excellent insulator.

Why does the door sweat if all the listed conditions are met? The reason for this may be lining it from the side of the living area of the surface with a material that prevents the penetration of warm air to the inner surface of the door and its heating.

And if the panel turned out to be vapor-permeable, and there is at least a small gap between the steel surface and the insulation, then the front door sweats inside, under the lining, but you don’t see it. As a result, it can quickly fail.

Recommendations of specialists

In order to have no questions to the manufacturers during the operation, why condensate is formed in cold weather, experts recommend to take into account the following points when ordering:

Separately discuss and order warming not only the door itself, but also the box.
Refuse to install at the doorfacing the street, peephole.
Do not install locks with vertical bolts on such a door or do not connect the thrust vertical drive in cold weather.