[Cob] was cob floor debates: now drainage

[Barbara Roemer]

Tys,

Sounds like you've carefully considered your drainage needs and generally
provided for them.  As you have a hill above you (if I understand your site
correctly), you're right about your "3" spots" being potentially
troublesome.  We have a little hill - only 2-3 feet high, about 5' away from
our slab (remember we didn't build this - it's an ill-sited renovated
garage).  But, local conditions obtain - that is, the ground beyond or above
the hill slopes gradually uphill further, all of it is undermined by rodent
tunnels and the open channels of a constantly-renewing-itself-conifer forest
where when a tree comes down or is overshadowed by its taller mates, the
roots die and leave more tunnels. Whenever it rains hard, which is several
times per winter/spring, the hillside gushes with water under higher
pressure than our 50 feet of head water tank provides.  Water spouts out of
the hillside and collects in a torrent running along that 5' wide path
adjacent to the house. It's more volume than a trash or sump pump can deal
with: we run one steadily through a heavy rainfall.  Of course the
foundation and slab get wet, as does the soil beneath.  Whatever vapor
barrier there might have been (and it looks like it was maybe 1 mil eons
ago) has deteriorated to the point that even weeks after a rainstorm, if the
dawg sleeps on her bed on the slab, condensation occurs under the bed.  That
even with only about 40% humidity today.

The point is that local conditions can vary so widely, it's impossible to
give you other than "what if" scenarios without seeing your site and soil.
It sounds like you're doing a good job of worrying it - I would put in the
vapor barrier, but I"m not on site, and that's based on my experience which
couldn't be much worse!

Keep batting it around here until you've figured it out - we all benefit
from each other's experiences.

Barbara