[Cob] Silverfish, Tornadoes, and Humidity

[Brent Flaco Wilson]

I was wondering about dry stacked foundations.  They would seem to provide 
excellent habitat to numerous insects, possibly amphibians, reptiles and 
small mammals.  Any thoughts on this.  Also if one wanted to use round rock 
for a footing, what would be the best "mortar" for this under cob walls.

>From: "Shannon C. Dealy" <dealy at deatech.com>
>Reply-To: dealy at deatech.com
>To: CarmenKittieCat at aol.com
>CC: coblist at deatech.com
>Subject: Re: [Cob] Silverfish, Tornadoes, and Humidity
>Date: Mon, 21 Mar 2005 13:21:49 -0800 (PST)
>
>On Thu, 17 Mar 2005 CarmenKittieCat at aol.com wrote:
>
>[snip]
> > potential problems with termites and silverfish. She offered  a 
>suggestion for
> > preventing termite problems, but then went on to describe a  problem 
>someone
> > has with silverfish, and she said she knew of no "nontoxic"  solution. 
>How
> > common is the silverfish problem and has anyone yet found a  nontoxic 
>solution to
> > the challenge?
>
>While there are silverfish and termites in this area, I haven't had
>problems with either one so far.  I think for silverfish if you eliminate
>damp areas and have a tight house, you eliminate both the attraction and
>anyway for them to get in.  Termites might be more problematic, but I
>think they also tend to like at least moist earth, so once your walls are
>set, if you can keep them dry, they are likely to find more hospitable
>places to burrow in.
>
> > And then, what about tornado resistance? Given that the roof might  come 
>off
> > during a tornado, how would the building itself hold up? Tornadoes are  
>rather
> > unpredictable, but generally speaking, with no regard to the potential  
>rain
> > involved, how well do curved cob walls hold up to tornadic winds or the
> > associated high winds in nearby ares during a tornado?
>
>Curved walls are better than square (more aero-dynamic), and the high mass
>of the walls would probably fare better than conventional wood
>frame structures since it would require stronger winds to move and/or lift
>the structure.  The rain is pretty much irrelevant, since it takes time
>for cob walls to soak up enough moisture to soften significantly, and
>tornados just don't last long enough (particularly in one place) for the
>cob to weaken.  Of course a direct hit by a really strong tornado will
>flatten pretty much anything, but if I had to be in one I'd take my
>current cob house over a conventional wood frame structure.
>
> > Finally, humidity. I have read that the cob walls are very slow to  
>respond
> > to temperature change, etc., but I am concerned about humidity--not rain 
>  so
> > much as the "thick" air, you know what I mean, and for extended periods  
>of
> > time. In the summer we can have weeks of H-E-double-hockeysticks where  
>the
> > humidity drives the heat index very high, day after day. Does the  
>humidity permeate
> > the cob walls at all? Not to mention the plaster, how  does that hold 
>up? Can
> > humidity be a problem over time, even though it's  merely one season out 
>of
> > the year?
>
>Cob will (to some extent) moderate humidity in much the same way it does
>temperature, by absorbing some of it and releasing it when the humidity
>drops.  The cob won't care about seasonal fluctuations in humidity,
>though your plaster might depending on what you use if the humidity is
>really bad.  I would tend to go with a good lime based plaster and (if
>desired) a lime based paint, as it tend to be more resistant to damage by
>humidity as well as less hospitable to mold and mildew.
>
>Shannon C. Dealy      |               DeaTech Research Inc.
>dealy at deatech.com     |          - Custom Software Development -
>                       |    Embedded Systems, Real-time, Device Drivers
>Phone: (800) 467-5820 | Networking, Scientific & Engineering Applications
>    or: (541) 929-4089 |                  www.deatech.com
>
>
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