cob design details

Eric Nielsen plato at
Sun Jan 2 12:13:11 EST 2000

Catherine --

Not to pick an argument here, but exactly who is "not recommending" cob below grade?  I would not be so silly as to assume that one could use simple raw earth-straw alone below grade, but eventually with adequate stabilization (portland cement) I would think that some form of earthen wall could be made "do-able" for below-grade applications.  As far as drainage goes, yes french drain set-up with adequate tiling, moisture barriers, good roof overhang, etcetc. are absolutely manditory up here in Iowa -- we get 2-3X the precip that you folks down in (the wonderland of) New Mexico get.  I guess I am interested to see how far the limits of cob design have been pushed in the past.  Wouldn't you think that *somewhere* in the history of monolithic earthen design that *somebody* has, relatively successfully, implemented a below-grade cob structure??  I suppose, if necessary, I could use conventional concrete or cinder-block outer walls, line interior surfaces with with a thck layer of insulation, and then cob over the insulation to provide thermal mass for the passive solar heating element of the structure.  Tangentially re: insulation -- my initial concept was to imbed a layer of insulation directly into the cob wall as a thermal break -- say roughly 12-15 inches of wall on the inside (interior surfaces) of the insulation and perhaps 8 inches of cob on the outside (exterior surfaces).  Any info on imbedded insulation in cob structures???

Speaking of New Mexico, am I correct in visualizing your facility as roughly halfway between Silver City & T-or-C??  What a gorgeous corner of the Earth!!  I shall definitely contact you next time I am in the area.

Thanks for your time and input -- Eric

  ----- Original Message ----- 
  From: the black range 
  To: Eric Nielsen 
  Sent: Thursday, December 30, 1999 7:21 PM
  Subject: Re: BWOB and more
  Hi Eric,

  Thanks for your interest. You'd be most welcome to stop in at the Lodge, and if you'd like to stay awhile, plug into what ever project is going on at the time. We do an informal work-exchange with "interns" as well as run the Lodge as a bed and breakfast. It would be best to call or email first, to check in.

  We might also be able to refer you to timely workshops and/or other people to see in the region.

  About cob below grade -- you don't read about it because it's not recommended. We did build a small "earth-bermed passive-solar" structure with cob on the south side. But the foundation, below grade, was rammed earth-bags atop dry stacked stone. We also installed a "french-type drain" on the uphill side at the lowest foundation level, to divert water around the structure. Careful landforming and landscaping uphill would also be wise, to prevent inundation.

  Best Regards,
  Catherine Wanek, Proprietor

  The Black Range Lodge 
  Bed & Breakfast
  119 Main Street
  Kingston, NM 88042 
  (505)895-5652 / (505)895-3326
  <blackrange at> 
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