Die Entwicklung eines mineralischen Feuchtespeicher‐Grundputzes

Abstract

Im folgenden Aufsatz wird die Entwicklung eines Feuchtespeicherputzes auf mineralischer Basis beschrieben. Im Rahmen eines schweizerischen Forschungsprojekts zur Restaurierung von historischen Gebäuden wurden unterschiedliche, als feuchtespeichernd bekannte Putze nach dem Nordtestverfahren untersucht. Durch die anschließende Neuentwicklung konnte gezeigt werden, dass sich der optimierte Feuchtespeicherputz von heutigen, marktgängigen Produkten durch eine bis zu 9‐fache Feuchteaufnahme auszeichnet. Die Forschungsergebnisse erlauben nun eine gezielte Veränderung der Feuchtespeichereigenschaften und somit des Raumklimas von Alt‐ und Neubauten auf einfachem Wege durch die Verwendung entsprechender mineralischer Putzsystemkombinationen.The development of a mineral based moisture buffering render. As part of a swiss research project dealing with refurbishment of historic buildings, different moisture‐storing renders were investigated according to the Nordictest method. By the subsequent new development it was shown that the moisture uptake of the optimized moisture buffering render is up to nine times higher than that of today`s products available in the market. The result of the research works enables a targeted modification of the moisture buffering properties and therefore of the indoor climate of old and new buildings on a simple way using appropriate mineral render system combinations.

Comparison of moisture buffering properties of plasters in full scale simulations and laboratory testing

“…Consequently, gypsum cannot be compared with these studies. Lime plaster performances are in line with Tittarelli et al [41] and Stahl et al [5] results, in which lime mixed with sand has the worst MBV performances (0.50-0.88 g/(m 2 • %RH)).…”

“…The laboratory test showed clay and gypsum plaster exchange more humidity than lime, while other studies showed similar moisture buffering values for clay [3,5,39], but gypsum presented in general moisture buffering values lower than 0.95 g/(m 2 •%RH). However, the moisture buffering results for gypsum presented by Stahl et al [5] and Santos et. al.…”

“…Through exposure of hygroscopic, vapour active, materials to the room air indoor humidity fluctuations can be moderated. The use of vapour responsive materials such as clay plaster reduces the peaks of internal relative humidity due to their good moisture buffering capacity [3,4,5].…”

A review on the buffering capacity of earth building materials

“…A study by Stahl et al (2013) investigated the improvement of the buffering capacity of plasters. Two clay plasters were included as reference in the study ('Lehmputz 1' and 'Lehmputzt 2'); following the Nordtest procedure the plasters were measured and showed moisture adsorption at 8 h of 59 and 53 g/m 2 .…”

A review of moisture buffering capacity: From laboratory testing to full-scale measurement

“…Some materials, described as hygroscopic, have the ability to passively control the indoor climate, reducing operational energy. Timber [7], clay [8] and other novel materials, such as zeolite [9] and mineral based plasters [10] reduce the peaks and valleys of internal Relative Humidity, due to their ability to adsorb and desorb moisture, a process referred to as moisture buffering [11].…”