You're welcome!
Yes, in the beginning care needs to be taken, as it cures over a period of months, though it hardens superficially in a few hours.
One build in Asheville, NC, for example, had mice manage to chew their way in early in the process, but thankfully hempcrete is also easy to patch. There are good YouTube videos that document the steps in that particular build.
And, once it cures, it's pretty much impervious, provided that care was taken in the build. The typical hempcrete wall is between 15" and 18' thick, with the hempcrete pounded into place (to eliminate air gaps) between wooden forms. From what I've read, it can be safely built up to about 15' without needing additional structural bracing.
When a section is completed, the forms are moved upward, and the next section is begun. All very user friendly, in terms of skills required, which basically comes down to being diligent in using a good level and setting the forms correctly.
I would love to build a home out of hempcrete, but realistically, we'll likely start with a small cabin first.
Like adobe, because of the thick walls, hempcrete homes are cheaper to heat and cool than typical homes, and are naturally cooler in summer and warmer in winter.
That said, like any sort of earth building it's a lot of work, but the labor pays off handsomely.
Again, I appreciate your informative response! I wasn't aware of the cheaper cost of cooling and heating. I'm curious as to when a massive transition will occur toward utilizing hemp. Further, I'm curious about any drawbacks regarding hempcrete and hemp builds. So far, I can only find a lack of demand—given the demonization of hemp plants in general. I suppose a lot of work is involved also, as you've said.
You're welcome!
I believe that this is the house I was talking about, which was the first permitted hempcrete house in the US. This video is from Nov 2009.
Once it starts to gain more acceptance as a building material, the fixed costs of building a house can go down dramatically, especially if the owners are willing to do much of the labor themselves.
This house has relatively thin walls, but the build was in Asheville, NC, which is in the South, and thus not subject to the weather extremes of the Great Plains, for example.