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joschi_0811 Aug 2015 01:32Hello,
I want to insulate the two exterior walls inside my office because in winter the dew point is reached, causing condensation to form. The temperature in the lower corners is about 3°C (37°F) when it gets really cold outside. Otherwise, the walls are resistant to driving rain and I can rule out rising damp. Currently, there is wallpaper on the walls, slightly moldy in the corners, beneath it there is filler compound, partially dispersion paint, plaster, and masonry.
My renovation plan is as follows: remove the wallpaper, scrape off any loose filler or paint, apply interior insulation, and then finish it with a suitable plaster or filler.
My question: Should I use calcium silicate boards or cork? Cork is less permeable to moisture than calcium silicate... What are the advantages and disadvantages to consider?
Thank you and best regards
joschi
I want to insulate the two exterior walls inside my office because in winter the dew point is reached, causing condensation to form. The temperature in the lower corners is about 3°C (37°F) when it gets really cold outside. Otherwise, the walls are resistant to driving rain and I can rule out rising damp. Currently, there is wallpaper on the walls, slightly moldy in the corners, beneath it there is filler compound, partially dispersion paint, plaster, and masonry.
My renovation plan is as follows: remove the wallpaper, scrape off any loose filler or paint, apply interior insulation, and then finish it with a suitable plaster or filler.
My question: Should I use calcium silicate boards or cork? Cork is less permeable to moisture than calcium silicate... What are the advantages and disadvantages to consider?
Thank you and best regards
joschi
J
jupartner11 Aug 2015 08:10Hello Joschi,
Wow, 3 degrees is quite low—I almost guess you measured that at night when the indoor air temperature was below 16°C (61°F), right? I also suspect there might be some additional source of cold beyond the usual. However, this does not significantly affect the choice of interior insulation.
I am also always in favor of natural insulation materials. I am not familiar with the moisture properties of cork. What matters here are the moisture storage capacity and the capillary moisture transport characteristics. Maybe you can get some information from the supplier. Compare those values with proven interior insulation systems like these:
Wood fiber insulation, for example, has been used together with clay plaster as interior insulation for many years. Both materials score well due to their moisture storage capacity.
Calcium silicate, on the other hand, transports moisture very quickly and itself does not support mold growth. It is initially a basement restoration board (without much insulating effect)—the actual insulation is done by follow-up products: lime-based boards with a thermal conductivity rating of 0.040 to 0.045 W/(m·K) (also called "mineral interior insulation boards," not to be confused with mineral wool).
These lime-based interior insulation boards (e.g., from Keim Farben, Ytong, Caparol, Sto, etc.) are plastered on the inside, and this interior plaster also acts as a kind of vapor retarder. Make sure you only use the plaster and adhesive mortar products tested by the manufacturer (this is called staying within the system).
I wish you much success,
Susanne Junghans
Wow, 3 degrees is quite low—I almost guess you measured that at night when the indoor air temperature was below 16°C (61°F), right? I also suspect there might be some additional source of cold beyond the usual. However, this does not significantly affect the choice of interior insulation.
I am also always in favor of natural insulation materials. I am not familiar with the moisture properties of cork. What matters here are the moisture storage capacity and the capillary moisture transport characteristics. Maybe you can get some information from the supplier. Compare those values with proven interior insulation systems like these:
Wood fiber insulation, for example, has been used together with clay plaster as interior insulation for many years. Both materials score well due to their moisture storage capacity.
Calcium silicate, on the other hand, transports moisture very quickly and itself does not support mold growth. It is initially a basement restoration board (without much insulating effect)—the actual insulation is done by follow-up products: lime-based boards with a thermal conductivity rating of 0.040 to 0.045 W/(m·K) (also called "mineral interior insulation boards," not to be confused with mineral wool).
These lime-based interior insulation boards (e.g., from Keim Farben, Ytong, Caparol, Sto, etc.) are plastered on the inside, and this interior plaster also acts as a kind of vapor retarder. Make sure you only use the plaster and adhesive mortar products tested by the manufacturer (this is called staying within the system).
I wish you much success,
Susanne Junghans
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