2020-09-06
Weeping
I live in a studio apartment, it’s nice, spacious, and located fairly centrally in Nijmegen. The only negative really is that it’s located about 2 metres below ground. Yes that’s right, I live in a basement, and every time I come back from work the walls weep in joy at my return.
The building is an old, recently renovated, red-brick structure, with thick walls. The basement, or really the cellar, was built without any actually floor. Rather some bricks were laid directly into the ground, with maybe some stone tiles laid on top of these (in its renovated state the stone tiles now have a layer of plastic and insulation on top with laminate flooring on top of this). The effect of this is that moisture leeches through the floor into the apartment.
Certainly, at the time when this building was erected, this was not really a problem as most building were not built to be air-tight. That is that there was always a certain amount of air exchange between the inside and outside, leading to a fairly even balancing of relative humidity. To be clear, this was not nessicarly by design (I need to looking further into this, the Dutch were already in the 16/17 hundreds fairly good at building on or near wetlands), but due to lacking tooling or materials to actually make the inside and outside of a build literally separated spaces.
Today though, most new builds are designed to
conserve energy as much as possible. This is done
primarily through insulation, which prevents heat (or
cold, really) from moving in or our of the building by
radiation. Being that air is a major vector to loose
energy to the outside, buildings tend to also limit air
exchange as well (not completely, especially for
building where people are, otherwise
:math:CO_2 and other gases may collect and
poison everyone). With this, there is a considerable
risk for moisture to collect and ultimately condense on
surfaces, such as walls. This is especially true in
basements as walls tend to be a lot cooler then the
inside air, leading to weeping walls.
Dehumidifier
A solution to this is to use some device which can remove moisture from air. A de-humidifier does this by essentially the same process as what causes moisture to condense on walls: it blows the air over a very cold (not freezing!) surface, and collects the water.
Funnily enough, this is actually how air conditioning became a thing. As industry grew, the need to accurately control relative humidity in factories and warehouses, for instance, become critical. By running air over a cold surface, not only do you remove moisture from it, you also cool it down. The actual workings of a A/C versus a de-humidifier are different though, in particular about where this extra ‘heat’ that is collected goes. If you want to know more, look it up.