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timber framing and cob  RSS feed

 
Peter Ellis
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Playing with design ideas for the future cob house. Considering roundwood timber framing as a significant portion of holding up the roof.
Thinking about stresses on that frame, movement when the wind kicks up, things along those lines.

All of which lead me to wondering what happens if you have a timber frame and then cob not just to infill but to encase the posts in the frame.

Would doing this make for a super supported rigid frame, or would the posts shift despite all the cob, and in shifting, would they break down the cob wall?

My imagination can see this working either way, and while the really rigid option sounds good to me, the one where it shifts about and creates a bigger and bigger crumbly hole in the cob wall sounds Very Bad.

Wondering if anyone has experience they could share?

Thank you.
 
Jay C. White Cloud
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Playing with design ideas for the future cob house. Considering roundwood timber framing as a significant portion of holding up the roof.
Thinking about stresses on that frame, movement when the wind kicks up, things along those lines.


I always recommend to folks not well versed in any building modality to have the plans checked and vetted by a PE, and/or experienced practitioners of a style. I am not fond, accept in restoration work, or being done by a well trained "mud builder" anyone tackling a "structural" cobb wall, so I commend anyone on the choice of an "infill method."

All of which lead me to wondering what happens if you have a timber frame and then cob not just to infill but to encase the posts in the frame.


Some traditional methods just "infil" other do encase, it all depends on the modality that is chosen.

Would doing this make for a super supported rigid frame, or would the posts shift despite all the cob, and in shifting, would they break down the cob wall?


No matter what vernacular or augmented system that one could select to employ, the timber framing should not "shift" in any way if done properly. Some systems are more tectonically sympathetic and enduring than other, Asian system vs. Western rigid systems for example, but all are solid when performed properly.


Wondering if anyone has experience they could share?


If you just search many of my posts I have written quite a few examples of this in different forms here at Permies.com. I would be glad to answer any specifics I am able to.

Regards,

j
 
Peter Ellis
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Thanks Jay. I have read quite a bit of your posting.
I do not recall my specific question being addressed.
Rigid is a relative term.
I believe you would acknowledge that any wood frame will flex under stress. One of the benefits of the material. Also a potential liability when closely integrated with a material that is almost entirely inflexible.

And there again is the crux of my question. Will movement of structural timbers encased in cob break down the cob structure?
 
Jay C. White Cloud
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Will movement of structural timbers encased in cob break down the cob structure?


It will not “break down the cob structure,” if the frame is built properly, is the short answer.

There is of course the caveat of how extreme an example one applies to the frame. Any frame, that is subjected to heavy enough tectonic forces is going to suffer the effects of such events, modern or traditional. There is evidence that many traditional systems endure much, much better in zones of chronic and severe seismic activity.

Japan is just one example of cobb infill systems that work under such duress. Turkey and other regions of the Middles East and Asia have their own.

Regards,

j
 
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