
If you're new here, you may want to subscribe to my RSS feed. Thanks for visiting!
I have had several clients of my consulting business call me after they started to plaster their straw bale house. The calls come with a similar voice over the phone: panic (sometimes mild and others extreme)! “My house is smelling musty.” That pretty much sums it up and you can imagine the concern. “Do I need to tear my walls out and start again?”
No. You don’t. In all of the cases where this has happened, the clients had several things in common. First of all, they were all working with the brown coat to some capacity. Second, they had sprayed a lot of water on the scratch coat to insure proper bonding of the brown. Third, and perhaps most importantly, the weather was moist and no heaters were used during the curing process.
It is good practice to allow the plaster as long as possible to dry and cure; however, not at the risk of saturating your bales with water. It is essential that the walls be sprayed down well enough for the brown coat to bond. Spray the walls the night before you plaster until the walls no longer accept water. In other words, until it runs freely down the walls. Spray them again in the morning before you start mixing your plaster to the same measure. That is all you need. Once you have finished plastering, keep the walls moist by all means. Do not over dampen your walls. Allow them to slowly cure for two days or so, and work them as necessary to stop cracks from breaking out. After a couple days, let them be and allow them to dry naturally. After a week or so, start introducing heat into the house to dry out any excess water in the walls. The best source, other than natural heat, is electric because gas heat will only increase the moisture in the air and thus the walls.
If you get musty walls, use the heaters to dry them out and open windows if the weather permits. It is not the end of the world and you will survive the trauma! That’s the good news.
Popularity: 4%
Like this? Click here to buy me a Wolaver's Organic Oat Meal Stout!About the Author
Andrew Morison is a licensed contractor specializing in straw bale and green construction. He has shown thousands of people how to build their own straw bale projects through his comprehensive series of instructional straw bale, concrete foundation, and plastering DVDs. You can check these out at http://www.LearnStrawBale.com.
Get Updates of New Articles and Posts
To be notified of new entriesblog entries and articles and to get our "7 Essential Steps to Straw Bale Success e-course" absolutely free, enter your email address below then check your inbox to confirm. More Info>>






























September 6th, 2007 at 12:36 pm
At 2:55 PM, Southern Sally said…
Nice blog site! This is my first time perusin’ this site and I like what I’m seeing.
I am wonderin’ if there is a more official way of testing the walls for moisture content rather than going by sense of smell alone. It scares me to think that there could be mold growth happening in the walls without my knowing it…I don’t have the best sense of smell!
Let me know…Southern Sally
September 6th, 2007 at 12:36 pm
At 10:56 PM, Andrew Morrison said…
Follow your nose…It always knows! I remember that from my childhood: Toucan Sam and Fruit Loops! Yes Sally, you can definitely use more accurate methods of moisture identification. A small hole can be drilled into the existing plaster and moisture meter sensors can be shoved into the bale. In fact, some people actually install the meters in the wall while they build with a monitoring station in the utility room so they can watch the moisture for the life of the home. In lieu of that, you can simply use a hand held meter with a probe long enough to reach the edge of the bale at the far side of the wall. Chances are the moisture levels will be high near the plaster for a while, due to the relatively large amount of water introduced into the wall during the plastering process. As long as the bales are under 20% moisture content, they cannot support mold growth, so even a wet wall will not allow mold to grow once it dries out. If you have high moisture levels and you smell mold, do what you can to dry the walls and retest the moisture often keeping track of any changes in a journal. Once the moisture levels are safely below 20%, you should notice the musty smell disappear in a week or so. Good luck.