[Cob] Mysterious foundation moisture issue -- rising damp?

[Michael Cantrell]

 Ziggy,
I'm going to go with condensation, too. If one area of the walls is
noticeably cooler, and that's the area that's wet, that's a strong clue.

What sources of humidity are there inside?
You cook outside only, right? Are you cooking anything on top of the
woodstove? (I'm loosely familiar with the layout from your blog.)
Drying any wet clothes?
There's no shower inside, right?

In that small of a space, just two people's breathing is going to get you
some moisture in the air... and that's a hard one to stop!

There are several direction you could approach the problem from:
-getting the air drier
-getting the wall warmer
-getting the air so much warmer that it won't condense on the wall
-letting it condense but keeping it from doing any harm

Good luck, looking forward to hearing how you solve it!

Mike In Ark



> Date: Mon, 24 Jan 2011 14:43:52 -0600
> From: Brian Liloia <evacindustry at gmail.com>
> Subject: [Cob] Mysterious foundation moisture issue -- rising damp?
> Hi there:
>
> I want to share a problem that I think is rising damp causing a pretty
> serious issue in my house. I have a two course urbanite foundation with
> clay/sand mortar above an 18" deep rubble trench, with ~18" thick cob
> walls.
> I'm located in NE Missouri.
>
> This winter, about a week ago, I began to notice the infiltration of
> moisture at the base of the wall inside -- some of the pieces of urbanite
> have a wet look (beads of water on the face), there are wet spots on the
> floor at the base of the wall, and the wall itself (12-18" up from the
> floor
> level) is in some places damp, or even icy (really only the NW corner
> here),
> and definitely has mold developing (a fluffy white mold that I have to
> weekly spray with vinegar and wipe away).
>