Tougher fire requirements and the desire to make
simpler designs have enabled construction companies
to go from the traditional well-ventilated attic to attic
with limited ventilation. Theoretically limited ventilated
winds should perform well. The problem you see if there
is construction moisture or external moisture sources.
Problems may occur when the small ventilation is not
able to remove moisture to the extent necessary.
Heavier constructions usually have a large amount of
construction moisture in the attic floor, which can be
transferred to the attic space. Heavier structures with
limited ventilated attics have not been studied
AK Consulting was commissioned to evaluate five attics
to a construction company erected in 2014 and 2015.
Former investigations showed that there was a risk
initially with respect to the excess moisture from
building moisture. This study was carried out with
theoretical calculations on a model of an existing attic
with moisture problems.
The present thesis was commissioned by AK
Consulting. It evaluated the data and reports from the
five attics and assesses them with the help of WUFI BIO
and made theoretical calculations in WUFI.
The study shows that attics with limited ventilations
work well initially and that the ventilation of the attic
does not lead to drier attics. Longer measurement
periods are required in order to see how the wind works
in the long term and in different outdoor climates. It is
difficult to determine the effect of initial
dehumidification of the winds. The attics have little or
no excess moisture over the measurement period.
The recommendations are to dehumidify attics initially
until further studies have been done on similar
structures. It is also important to continue monitoring
the attics in this study to follow up how they work in the
long term and during years with different climatic