[Cob] Moisture Barrier Mobile Home

[Shody Ryon]

I think the vinyl siding and blue foam might be a
moisture barriers but one of the other things moisture
barriers do is prevent wind from entering though
little cracks. So, I believe the narrowness of the
individual pieces of siding (if indeed it is narrow)
work against its effectiveness. The same goes for the
foam, as it fits in between the studs (?), unless it
was sprayed in or caulked in. the moisture barrier is
normally like tar paper about 3 feet wide and goes on
the studs covering the joints between the studs and
the insulation. The joints in the paper moisture
barrier itself are just the paper (felt, Tyvek, etc.)
overlapping 6 inches to a few feet or so. All of that
is sandwiched between the siding, drywall or paneling
and the studs. When installing it on the outside of
the studs, the first course normally would go on the
bottom horizontally around the structure, and each
course would go higher, like shingles, if applying it
on the inside of the structure the top course goes on
first and the bottom last, again, like shingles, at
least that is the way I did it. Again, when it is
covered the sandwich effect makes it seal. But almost
every house I worked in southern California had some
termites, which I believe is an indication of moisture
being present, so I think the basic concept, or some
part of it, is flawed.

Another concern I have about your plan is the
expansion and contraction of the cob and the studs. I
think it would be a lot better to present a uniform
material to the weather/elements with joints that are
well planned, i.e. the joints in the 1 foot (?)
courses of un-dried cob work well. I presume adobe and
a way to “mortar” the bricks together that has stood
the test of time, cob in-between studs? Perhaps that
is “English Tudor style”, which has stood the test of
time, I don’t know. I assume the wood used in Tudor
building is of a type that can withstand the weather,
and I don’t think the mobile studs will, even with
exterior paint or varnish. Perhaps you are planning on
addressing this issue with the extra layer if cob on
the outside. From what I can see, the cob is usually
kept wet for making joints strong. I don’t know if you
can add cob on the outside, or if you do, would that
be more of an earth plaster? If it is an earth plaster
can it be applied without something at the bottom for
it to sit on? If it needs that can something be put
there temporarily (or permanently) as a form or
support?
Shody

--- Lee Courtney <heylee34 at hotmail.com> wrote:

> At this point I am still experimenting and unsure of
> what exactly I'm going 
> to do.  

<snip>

 If so, could I
> also use a bit of cob on 
> the exterior to thicken up the walls.  I'm assuming
> cob will stick just fine 
> to light straw clay.
> 
> Lee


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