Abstract
In the framework of the research programme Climate 2000, the Norwegian Building Research Institute is running field exposure tests of claddings on an experimental building in Trondheim, Norway. The eastern and western façades are divided into fourteen fields respectively, using different material qualities, painting systems and assemblies concerning building physics. The building is equipped with temperature and moisture measuring devices, continuously logging data since January 2004.
Data gathered from January 1, 2004 until July 31, 2004 are analysed and special attention is directed to the fields of the façade containing untreated wood. These fields contain fast and slow grown Norway spruce (picea abies) respectively, and the objective of this investigation is to study how different material qualities influence the moisture conditions of the cladding. In addition to this, the measured data were compared to data logged at the meteorological station located on the same site, in order to see if and how the moisture data mirror the climatic conditions.
At this point of time no clear conclusion can be drawn regarding the different moisture contents of the two material qualities. Though, the moisture content of the fast grown material seems to vary more than for the slow grown one. Crack formation due to greater variations in moisture content can be interpreted as a first sign of differences in the moisture condition of the two material qualities. This can lead to increased moisture absorption by and by.
Additionally, it was investigated if and to what extent the measured moisture content reflects meteorological parameters. It appears that by adding a time delay of 12 hours the goodness of fit, namely the coefficient of determination, can be improved significantly from an average of 0.5 to an average of 0.97. That means that 97 % of the measured values of moisture content can be explained by the chosen meteorological parameters.
The results provide useful information considering further investigation regarding the durability of wood materials exposed to climatic strains.
Data gathered from January 1, 2004 until July 31, 2004 are analysed and special attention is directed to the fields of the façade containing untreated wood. These fields contain fast and slow grown Norway spruce (picea abies) respectively, and the objective of this investigation is to study how different material qualities influence the moisture conditions of the cladding. In addition to this, the measured data were compared to data logged at the meteorological station located on the same site, in order to see if and how the moisture data mirror the climatic conditions.
At this point of time no clear conclusion can be drawn regarding the different moisture contents of the two material qualities. Though, the moisture content of the fast grown material seems to vary more than for the slow grown one. Crack formation due to greater variations in moisture content can be interpreted as a first sign of differences in the moisture condition of the two material qualities. This can lead to increased moisture absorption by and by.
Additionally, it was investigated if and to what extent the measured moisture content reflects meteorological parameters. It appears that by adding a time delay of 12 hours the goodness of fit, namely the coefficient of determination, can be improved significantly from an average of 0.5 to an average of 0.97. That means that 97 % of the measured values of moisture content can be explained by the chosen meteorological parameters.
The results provide useful information considering further investigation regarding the durability of wood materials exposed to climatic strains.