Diffusion of water vapour through external wall with thermal insulation on inner side

V nekaterih primerih, kot so na primer objekti stavbne kulturne dediščine, smo prisiljeni namestiti toplotno izolacijo na notranji strani stene. Sprememba ovoja stavbe lahko pripelje do kondenzacije vode v sklopu novega ovoja, do uničevanja konstrukcije zaradi gnitja lesenih delov in zmrzovanja konstrukcije, obenem pa ob ustreznih temperaturnih in vlažnostnih pogojih pride do razvoja plesni in gliv, kar vpliva na zdravje ljudi in kakovost bivanja v stavbi. Izbrane toplotne izolacije (toplotnoizolacijski porobeton, ploščo iz kamene volne, kalcij-silikatno ploščo, ploščo iz penjenega stekla) smo testirali na gradbenem sklopu zunanje stene, sestavljenem iz izolacije na toplotni strani in zidu iz opeke normalnega formata. Najboljše rezultate toplotne izolacije in preprečevanja kondenzacije vodne pare v sklopu smo dobili v primeru kamene volne s pravilno nameščeno in nepoškodovano parno zaporo na topli strani ter plošče iz penjenega stekla. Treba pa je opozoriti, da že zaradi majhne poškodbe parne zapore difuzijski tok vodne pare v sklop močno naraste in v primeru dovolj nizke temperature na hladni strani lahko vodi do kondenzacije in celo zmrzovanja vode v sklopu. Z uporabo Glaserjeve metode smo ocenili količino kondenzata in hitrost sušenja v opisanih gradbenih sklopih preko celega leta za vremenske pogoje v Ljubljani.In some cases, for example, in buildings that are a part of architectural cultural heritage, we are forced to install the thermal insulation on the inner side of the wall. However, such renovation of the building envelope may result in the condensation of water within the new envelope, degradation of the construction due to the decomposition of wooden parts and freezing inside the construction. In addition, new temperature and humidity conditions, can also lead to the development of mould and fungi, which affects people’s health and the quality of living inside the building. The selected thermal insulations (aerated cellular concrete, mineral wool, calcium-silicate, foam-glass) were tested. Consists of an insulation on the warm side and a normal-format brick wall on the cold side. As far as thermal insulation and the prevention of condensation of water vapour in this building element are concerned, the best results were obtained using mineral wool with an appropriately installed and undamaged vapour barrier on the warm side and a foam-glass board. It must be stressed that even a small damage to the vapour barrier can cause a significant increase in the flow of water vapour in the building element. In a combination with low temperatures, it can cause condensation on the cold side or even freezing of water in the building element. Using the Glaser method, we assessed the amount of the condensate and the drying rate in the building elements described for weather conditions throughout the year in Ljubljana