Rethink Your Life!
Finance, health, lifestyle, environment, philosophy
The Work of Art and The Art of Work
Kiko Denzer on Art
[Cob] plastic jugs in walls?Henry Raduazo raduazo at cox.net
Fri Dec 11 16:14:45 PST 2009
John: The walls in Coquille are two stories high but 6 foot 6 inch stories. I do not think Coquille is in an earth quake zone so that may not be a consideration. Washington, DC is not an earthquake zone so when I figured the weight of my roof divided by the number of square inches in the wall I got 10 to 20 pounds per square inch, well within the load bearing capacity of cob. The rules applied to adobe are excessively conservative for cob. It is impossible to get the wet mud mortar to stick to dry mud bricks so the mortar joints form fracture lines which do not exist in cob. I build children's playhouses out of cob because if I built a playhouse in a public park from adobe people would be able to nock the bricks off the wall with their fist. When I build a playhouse from cob you need a sledge hammer to destroy the walls. Try making two a small test walls 4 inches thick and destroying them. There is simply no comparison between adobe and cob. Have you tried searching the CobWeb for articles about earthquakes Issue Twenty Winter 2005 they did a seismic test on cob and it stood up to level 8 on the Richter scale. Of course a test like that is a meaningless because the structure was built by experienced cobbers who knew the building would be tested and built accordingly. My walls are slopped together rototiller cob made with chopped straw and probably not a fraction as good as cob walls built specifically to withstand earthquakes. Still they are impressively strong. Ed On Dec 10, 2009, at 10:27 PM, john fordice wrote: > Ed, > Based on historic seismic survival of adobe buildings, and some > research that was also done for adobe, a wall height to thickness > ratio of 7 to 1 has good seismic survival capacity. In the absence > of similar tested data for cob, I use this ratio when designing and > building cob walls. At 7" thick, this would give a height limit of > 7x7 = 49". What is the height of the walls you are describing? > john fordice > > On Dec 10, 2009, at 7:16 PM, Henry Raduazo wrote: > >> If you are making good quality cob the wall can be as thin as 7 >> inches. At cob cottage in Coquille they have been retying bales of >> straw and chain sawing them half. The half bales are stuck in the >> wall and this results in an insulation layer on the outside of 7 >> inch thick cob walls. It saves tones of cob. >> I just finished putting a cob wall on top of two cinderblock >> retaining walls 7.5 inches thick. Two 7 inch thick cob walls >> support 12 foot living roof 50 pounds per square foot. They are >> short cob walls with a good overhang so I expect no trouble >> supporting the weight. >> Ed >> On Dec 10, 2009, at 2:46 PM, john fordice wrote: >> >>> Tys, >>> I'll venture to say (without really being able to prove it) that >>> it will weaken the wall. A cob wall gets it strength by being >>> thick. A structure resists forces acting on it by being made as >>> continuous as possible. Making a void in the wall will create a >>> weak spot which compromises the continuity of the structure. I >>> would not do anything which creates voids in the cob based on >>> this reasoning. >>> john fordice >>> >>> On Dec 10, 2009, at 10:07 AM, Tys Sniffen wrote: >>> >>>> So, as my walls get up over 7 feet high, I'm starting to >>>> remember how lower >>>> down, when I had them laying around, I would toss in the >>>> occasional urbanite >>>> chunk to take up some space. >>>> >>>> Now I'm starting to think about tossing in some one gallon >>>> plastic jugs >>>> (vinegar jugs, that are slightly thicker plastic than the common >>>> 1 gal milk >>>> jug) again, to take up space, but also I'm thinking having a >>>> void in the >>>> wall that size could insulation in a way, and, of course, would >>>> make my tall >>>> parts a bit lighter. >>>> >>>> Does that sound like a bad idea to anyone? >>>> >>>> Tys >>>> >>>> >>>> >>>> >>>> _______________________________________________ >>>> Coblist mailing list >>>> Coblist at deatech.com >>>> http://www.deatech.com/mailman/listinfo/coblist >>> >>> >>> _______________________________________________ >>> Coblist mailing list >>> Coblist at deatech.com >>> http://www.deatech.com/mailman/listinfo/coblist >> >
Solar powered hosting (from our cob office building) provided by: DeaTech Research Inc. using Debian Linux based servers. We highly recommend, use, and provide support services for Debian Linux.
If you should have any problems with this page or website, please send email describing the problem(s) to: email@example.com
Last Modified: Friday, 11-Dec-2009 17:10:53 PST
If you wish to be permanently blocked from ever being able to send email to this domain, send your SPAM messages to: firstname.lastname@example.org