We appreciate stories from readers who document their projects and want to share what they’ve learned with others. Today’s blog post is from long time contributor Patti Stouter. She’s published some of the best free articles on the Internet. These articles (and everything else related to earthbag building) is archived at EarthbagBuilding.com.
“Lime plaster is more water-resistant than earthen plaster. Yet a relatively thin layer of this lime and sand protective coating can be applied on top of earthen plaster. Lime survives in humid, frosty places if the top of the wall is protected by a roof overhang.
The earthbag test wall in the foreground was plastered shortly after the earthbag shed shown in the background, during last fall. Both are in Holmes, NY which experiences frost but had mild weather during the past winter. They were both plastered with the same materials- first earthen plaster and then lime plaster on top. They were done by Patti Stouter, a relative novice at plastering.
The only difference is that the test wall had no roof overhang. It started out with a piece of tarp tied around the top, held down by some rocks. This blew partly off during the winter. I assume that rainfall soaked down between the lime plaster and the bags. It could have caused the earthen plaster to expand even without the added stress and expansion of freezing weather.
The lime plaster on the shed was in perfect condition. Lime is a very sturdy wall covering- if it is protected at the top.
I’d love to see details that work for using lime plaster in this type of climate on a site wall. The Japanese tile-roof topped walls are the only example that comes to mind. And they have a definite overhanging roof.”