Temperature and moisture modelling of rendering on light weight constructions
2005 (English)In: Proceedings of the 7th Nordic Symposium on Building Physics in the Nordic countries, 2005Conference paper (Refereed)
Rendered light weight constructions have a low thermal inertia witch makes them especially sensitive towards changes in temperature. The lack of thermal inertia causes the construction to give a much quicker response to ambient temperature. Calcium cement rendering is a commonly used material for weather protection but will expand and shrink with temperature and moisture changes. When the changes occur rapidly the fast movement of the material can cause it to crack and lose its moisture-proof characteristics. To study the drying out of the rendering, the phenomena was simulated using numerical calculations. A comparative calculation model with coupled heat and moisture transfer was created to evaluate the effects of mass transport on the heat distribution. The construction studied is a so called Symphony outer wall element which is a light weight construction. The rendering layer is assumed to have been saturated after a rain period. The drying out of the construction during a five day period is then studied. The calculations performed with the first model show large variations in temperature and moisture content which may cause the rendering to crack. The results are then compared with the second calculation model with coupled mass and heat transfer calculations which takes into account the thermal inertia of the moisture and its effects on the temperature variations. The purpose of this is to try to evaluate the significance of mass transfer in temperature simulations.
Place, publisher, year, edition, pages
rendered light weight constructions, mass and heat transfer, Capillary suction
IdentifiersURN: urn:nbn:se:kth:diva-6814OAI: oai:DiVA.org:kth-6814DiVA: diva2:11629
QC 201009062007-02-272007-02-272010-09-06Bibliographically approved