What is Water Vapor Diffusion in Walls, Why Does It Occur?
Diffusion occurs as a result of condensation in the structure, temperature, different humidity numerical values and different vapor pressures occur in both directions of the structure. Thanks to the very small pores in each element, it causes the water vapor to move.
What Happens as a result of Condensation of Water Vapor? Heat Insulation, water vapor condensation with exterior cladding , In other words, can water vapor diffusion be controlled?
The water vapor transfer mechanism is similar to the heat transfer mechanism. The vapor permeability resistance took the position of the heat permeability resistance, and the pressure difference took the position of the temperature difference in the heat transfer. The consequences of diffusion damage occur after a long time. This is because water vapor travels much more slowly than heat. In order to prevent this problem, it is recommended to use a vapor barrier in coordination with heat insulation material .
The vapor permeability of a building material is defined by its resistance to the passage of steam. This factor shows how many times less vapor the material passes than the air layer of the same thickness.
The gaseous water vapor in the air goes from the side with the most heat to the side with less pressure, just like the heat flow. The higher the temperature and the relative humidity, the higher the vapor pressure.
If the temperatures of the two adjacent spaces are the same, then the steam flow side is towards the space with less relative humidity than the one with high relative humidity.
Insulation of spaces from the inside is also inconvenient by building physics . If insulation from the inside is inevitable, then an ideal vapor barrier should be used on the hot side of the sheathing . In principle, it is the right move to apply thermal insulation in buildings to the outside.