Building Codes for a Cob house

[Larry Caldwell]

Originally Posted by salo

Hi folks!
I and my boyfriend plan to move to the Oregon, buy some acreage in a very rural area, and build a house from cob. We didn't pick the county yet because of the following - how we can found out what county doesn't have a building codes of just have a little? I know there are some areas in US that county doesn't issue those rules for building and people can build homes from everything they want - cob, straw bale, earthbags, mix.. We want as much freedom as possible and some restrictions will not allow us to have it.
I will greatly appreciate if someone can point it out this question to me and help with finding the needed information.

Oregon codes are statewide, and the same wherever you go. That doesn't mean nonstandard construction is illegal. For some examples, take a look at

http://www.treehouses.com/treehouse/treesort/home.html

This was constructed with permits and meets all building codes.

DorothyAinsworth.com

Also constructed with permits.

If you can meet structural requirements, you can build your house out of anything you like. Straw bale houses are popular, typically with a steel frame that meets seismic codes, and the spaces filled with bales and plastered to seal them up.

You might want to rethink your choice of materials. The lastest word is that Oregon has a 37% chance of a magnitude 9 earthquake in the next 50 years. The nice thing about wood houses is they don't have a lot of mass in the air to fall on you and kill you in your bed. I can see how you could use wire mesh to give the cob some cohesion in an earthquake, but why bother?

[Brenda-by-the-sea]

Originally Posted by Larry Caldwell

If you can meet structural requirements, you can build your house out of anything you like.

True. How do you meet structural requirements? Broadly speaking, there are two paths:

1. The prescriptive path: if you build your house "according to code" (the prescriptive requirements are posted on the BCD website), the plan reviewer will most likely approve your construction drawings without an engineer's stamp. A house built prescriptively will automatically meet compression load, shear load, wind load, seismic resistance. IECC energy efficiency and other requirements because nominal lumber, concrete, insulation and plywood all have known engineering values that have been incorporated into the code's tables.

2. The engineered path: if anything on your house varies from prescriptive requirements, then the construction drawings need to bear the seal of a structural engineer licensed to practice in Oregon. The engineer will do the math for the load, seismic and energy-efficiency requirements and may specify particular connective devices or holddowns. He/she may also tell you that you can't do certain things that you wanted to do. This isn't as bad as it sounds. It isn't always easy to find an engineer who is sympathetic to the wants of the green-builder, but there isn't much building going on at the moment, so your chances are good. It may cost a few thousand dollars. That probably sounds like a lot of money, but reckoned into the overall cost of the house, it's small potatoes...money well spent if you want to go this route. Once you have an engineer's stamp, the plan reviewer and building inspectors feel that they are off the hook because someone else is taking responsibility for structural liability.

Cob is one of the world's commonest building materials and it has a good track record, especially for cradle-to-cradle sustainability. It's shocking how much toxic waste there is in traditional building debris when the buildings are demolished. As long as the house you want is quite small, cob can be a sensible choice.

[sneffy]

hey salo,

im also planning on building with cob in oregon.. any chance you could contact me and let me know how it's going with you? has anybody made you tear your house down yet? i'm in love with cob and would love to talk about it. stephanie neverforget123@hotmail.com

[Steve Pickering]

Four year old post and nothing since 2010, not likely.

[Nurse Bishop]

Why didn't you just tell me this yesterday, Mr. Caldwell? This is what I asked you privately about my agricultural building idea. The post of Brenda by the Sea is most useful.

[JStandeford]

See Stone Haven: My Stone Haven the first permitted cob house in Oregon.