Moisture content changing of a historic roof structure in terms of climate effects.

Timber is a widely used material in construction. The moisture content has a significant impact on the mechanical and physical properties of it. This paper studies how the moisture content values are directly connected to the climate conditions, especially temperature and relative humidity, by measuring these factors for a non-renovated historical timber roof for a one-year period, combined with meteorological data for Pécs since 1901. The fluctuation in moisture content values created instability in the water content of the structural elements due to absorption and release of water in order to reach the equivalent moisture content point. This process led to continuous volume increase-decrease of the timber, thus to formation of cracks, discoloration and harmful fungi development. [ABSTRACT FROM AUTHOR]