[Cob] Bearing loads--it all depends?

[Amanda Peck]

It certainly can be done without a problem.  It does all depend on site 
preparation, how you mix your cob, how much water gets on your cob, during 
or after building, where you've put the load bearing walls and 
buttresses--and if you need them--etc. etc. etc.  The guy who's probably 
going to help me build a straw bale house this coming spring is nervous 
about that, so we'll probably go with putting the roof up first, which has 
other advantages (for both bale and cob), but I'm planning on rainwater 
harvesting, so that roof will be neither heavy nor living.

I think I've seen calculations for living roofs somewhere.  That may be what 
you need at least as much as you need calculations for cob.  Does one of Rob 
Roy's books have those?  I don't have a copy of The Had Sculpted House 
handy, but that book is big on living roofs.

And I think we've had threads here on living roofs before, probably 
including weight calculations.

There are plenty of pictures around--like the widely reproduced--French--one 
on the cover of the Joseph Kennedy (et al) Art of Natural Building.  It's a 
pretty good introduction to the general topic of natural buildig, and 
Michael Smith is one of the co-authors--co-editors--since it's an anthology. 
  Library or dirtcheapbuilder--Amazon says it's unavailable, but you can see 
the picture on the cover here:

"http://www.amazon.com/exec/obidos/tg/detail/-/0865714339/qid=1066915686/sr=1-2/ref=sr_1_2/103-6977152-4198211?v=glance&s=books"

Although I believe that there are plenty of calculations for adobe and 
rammed earth--which are what seem to be referred to by cob builders looking 
for structural answers.

You might also take a look at this book on rammed earth (and straw bale), 
specifically from a structural engineers point of view.  
(dirtcheapbuilder.com really does have better service than Amazon, and 
besides it supports someone who contributes generously to the list)

"http://www.amazon.com/exec/obidos/tg/detail/-/0964471817/qid=1066914873/sr=1-8/ref=sr_1_8/103-6977152-4198211?v=glance&s=books"

.....................
Michael Colbert wrote:
What can you tell me specifically about cob's ability to bear loads -- heavy 
post and beam ceiling and possibly a heavy sod roof? Any personal experience 
or mathematical quanification? Thanks!

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