Just thought you might like to see what has happened to our walls this winter.
See photos here:
http://tinyurl.com/db7ank
http://tinyurl.com/c9q6jc
http://tinyurl.com/bb55z2
http://tinyurl.com/aw5eg7

The darker spots are locations where the moisture from the interior was starting to come out. The clay itself is soft to the touch. We are now glad we didn’t finish the outside last coat.

We think it happened when the natural moisture from the house tried to get out.. The hot air from within the house rose and took the moisture with it. The moist air found the less compacted areas (or so we think) near the top of the walls. The moisture originally came from the humidity naturally created in our house (cooking , breathing, drying clothes…).

There are two problems with this – firstly the soft clay may debond from the finish coat (lime coat) during the thaw / freeze cycle that will occur in the spring and secondly we may have too much residual moisture in the walls and we could get significant rotting of the bales.

We will probably have to scrape the clay off, repack the areas around the bales and then put the clay coat back on. (a difficult task because of the studs!). Our current plan for the exterior is to use a lime coat for the finishing coat but when we do, it will be less permeable than the inside walls. This could cause the moisture to collect and when it does release from the bales it could cause a debonding between the clay and lime coats. We think that we may have to redo the inside walls with a coat that then is less permeable than the lime coat on the external. Our current thought is to use a siloxane paint coat or other type of paint. That will wreck the natural look and make me sad… but at least the walls won’t rot.

We didn’t notice it last year or perhaps it it didn’t happen because we didn’t have such a prolonged cold period. The cold air froze the moisture at some point in the bales and last week, when it warmed up outside, the moisture continued its outward journey and showed up as wet clay.

We could make better use of the H-vac ventilation as well as the hood over (behind) the stove….but that requires a change in habits….might be as hard as giving up chocolate!

If any one has any other ideas please let us know what you think.

Maryann and Kevin