TVBH-5054 - Byggnadsfysik - Lunds tekniska högskola

Summary
Title: The drying rate of exterior walls of a wet room
- A comparishon between three architectonical solutions
Authors: Karin Grimbe and Linnéa Nordqvist
Supervisor: Lars-Erik Harderup
Department of Building Physics
Lund Institute of Technology, University of Lund
Complex of
problem:
The costs of moisture damages ought to be reduced by increasing the
amount of time spent on moisture dimensioning. Moisture dimensioning
results in architectonical solutions that consider an unexpected moisture
load, for example damage caused by leakage and exposure to excess
moisture from the production phase. The costs of these damages should
be reduced by the use of more forgiving architectonical solutions. The
question this report attempts to answer is: “Does the architectonical
solution with the vapour retarder Halotex D50 work satisfactorily as a
more forgiving solution than the conventional solution with or without a
polyethylene vapour barrier?”
Purpose: The main purpose of this study is to investigate differences concerning
the forgiving qualities, drying rate and utility for three different
constructions of light-weight wet room exterior walls. The study also
investigates the profits and drawbacks of installing the Honeywell HIH-
3610-002 humidity sensor in the walls.
Method: The drying rate of gypsum board in three different wet room exterior
wall constructions evaluates. In a laboratory the drying rate is measured
in a full-scale wall using humidity sensors placed inside the
construction. Corresponding simulations were also performed in the
computer program 1D-HAM.
Conclusions: A comparison of the three wall constructions shows that the wall with
the vapour retarder performs in between the two other constructions. The
construction with the vapour retarder is more forgiving in order to allow
wet materials to dry out quicker compared to the wall with the
polyethylene layer. The vapour retarder is also more user-friendly than a
wall without a vapour barrier. A wet room exterior wall with a vapour
retarder works well as a forgiving alternative to the traditional
architectonical solutions with or without a vapour barrier.
IV
The computer program 1D-HAM, which is used for additional drying
simulations, does not yield satisfactorily results. The program disregards
several parameters and it is questionable to whether or not it is
applicable to this kind of wall. The program is to be considered as a
guide. The result indicates how the drying of the walls appears to be, and
can be used to compare the relative drying rates of the different wall
designs in different climates. Since the program does not handle
temperature and moisture dependencies in the input data, the reliability