Moisture Monitoring during an Artificial Weathering Test of a Cultural Heritage Compatible Insulation Plaster

The majority of the building-stock from before 1900 has been erected with natural hydraulic lime-based mortars in massive masonry. Due to the low modulus of elasticity of lime-based mortars there has never been a need for dilation joints in old masonry structures. Changes in shape as a result of expansion and contraction, due to hot/cold cycles, could be “followed” by these masonry structures without damage. Moreover, lime-based mortars have a high vapour transmission rate, beneficial to the breathing capacity of monolithic historic masonry. These two most important characteristics have been taken into account when selecting natural hydraulic lime as binder for a Cultural Heritage compatible insulation plaster which was developed within the EU-Project EFFESUS (www.effesus.eu). The developed plaster was tested successfully in a so-called EOTA-wall test according to ETAG 004 [1]. Additional to the normal temperature and humidity monitoring within the test chamber, plaster and supporting wall were equipped with impedance sensors and other sensors to monitor material moisture behaviour. The results show moisture uptake and drying during the different test phases. Differences occurred depending on the material of the supporting wall.