a brand spanking new youtube video:

Hi all.

Just been thinking...

Obviously the loads that bermed/wofati/underground walls have to withstand, both vertical and horizontal, are very significant.
I'm currently of the opinion that  properly insulated earthbag laid in profoundly curved/circular shapes would be the best option for exterior walls rather than lumber.

Anybody else care to contribute?

I think you underestimate the raw strength of a proper pole structure.

I see the lumber to be faster and stronger as well as easier to seal wiht the poly although I suppose it could be used behind the bags.  Earthbags may have some locking potential and more if stabilized with portland cement but I would trust the wood more with the load of an underground structure.

I find 2 inch to be sufficient for an 8' span but 1 inch is only good for about  4' span, and that can vary with soil type.

Earthbags could still be an option though.

Ok.

Having thought about it, a profoundly curved/circular pole structure wall would resist horizontal forces quite well if properly braced high in the structure.
If you think about the the prevalence of arches in the massive structures of religious architecture you will start to understand the awesomeness of the curve.
Lay that bad boy on its side and just watch it resist horizontal forces.
Flat surfaces (for example flat roofs) cannot withstand heavy loads in their centre without supporting beams, the same can be said for flat walls loaded horizontally.
Hence the curvature.

You should really think of a properly built earthbag structure as monolithic rammed earth, rather than bags of loose dirt. Arch that baby up, and check the awesome that it brings. (It's one of the real advantages of earthbag over other mediums.)
Cement tends to draw in and hold moisture, which is bad news for earth sheltered structures, and Concrete is also a great medium for mould to grow in. I'd personally try to find an acceptable alternative before using cement.

Great video Paul!

So, since a significant portion of this house is exposed walls (not earth sheltered), what's Mike doing for insulation on those walls??

This is the ridgetop house Mike describes in his book?  Lots of glass.

You've got a lot more nerve than I do standing right on the edge of that roof!!!

Bill

I know nothing about insulation.  I don't remember seeing any there. 

Mike insists that this is the ridgetop house from his book - I guess I just don't see it yet.