Hygrothermal Behavior of Finnish Building Exterior Walls
Subba, Abhishek (2015)
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Lataukset:
Subba, Abhishek
Hämeen ammattikorkeakoulu
2015
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-201502102072
https://urn.fi/URN:NBN:fi:amk-201502102072
Tiivistelmä
The main problem with the buildings in Finland is most probably moulds growing inside the building components. Due to the very humid climate of Finland, the chance of mould problems is very large. During winter, the temperature difference between the indoor and outdoor environments is very large. Moisture travels with air currents. When air and moisture moves from warm side to cold side of the wall, moisture condenses onto the cold sheathing or cool drywall. This phenomenon can rot the insulation layer and degrade the thermal transmittance of the wall.
The main objective of this thesis study was to look for the main causes behind the moisture and heat loss problems. The highlight of the research was the position of vapour barrier and the thickness of the insulation layer. The vapour barrier position can always affect the moisture condensation process in the wall. The vapour barrier must be kept in the warm side of the wall so that the moisture flowing through the wall does not condensate. The thickness of the insulation layer affects the thermal transmittance. The heat loss decreases while the insulation thickness increases but at the same time the insulation thickness also increases the cost of insulation. This means that the need of optimization of wall material, especially insulation material can be economical and effective.
This thesis study process was first theoretically analyzed and was practically tested. The wall was designed using Finnish National Code and later tested using the weather simulating chamber. The findings were different in all test phases. When the wall has a construction fault, even a small hole can cause frost to accumulate in the exterior gypsum board. This accumulated frost can melt in warmer days and can rot the insulation. This thesis study can be used as a reference for further studies in the similar topic.
The main objective of this thesis study was to look for the main causes behind the moisture and heat loss problems. The highlight of the research was the position of vapour barrier and the thickness of the insulation layer. The vapour barrier position can always affect the moisture condensation process in the wall. The vapour barrier must be kept in the warm side of the wall so that the moisture flowing through the wall does not condensate. The thickness of the insulation layer affects the thermal transmittance. The heat loss decreases while the insulation thickness increases but at the same time the insulation thickness also increases the cost of insulation. This means that the need of optimization of wall material, especially insulation material can be economical and effective.
This thesis study process was first theoretically analyzed and was practically tested. The wall was designed using Finnish National Code and later tested using the weather simulating chamber. The findings were different in all test phases. When the wall has a construction fault, even a small hole can cause frost to accumulate in the exterior gypsum board. This accumulated frost can melt in warmer days and can rot the insulation. This thesis study can be used as a reference for further studies in the similar topic.