Glenn Herbert

The question is whether the emergency shelter is to ride out an extreme event, or shelter after the event. If it has to survive the extreme event, it probably has to be already up and secured, not temporary. The structure described would need much more construction to be even semi-permanently up and in the weather.

I notice that, aside from the unavoidable waste from panel geometry, the panels could all be made a couple inches bigger from the 4x8 sheets, making the whole structure maybe 6" bigger in diameter.

I do think that in terms of usable space beyond raw floor square footage, you could get pretty close to the same with ten sheets of plywood making an 8' x 8' cubish structure with a gable roof and 6' eaves and 8' ridge. The parts would be much easier to make and quicker to assemble, and very easy to waterproof. With 12 sheets, you could make an 8' x 10'-8" structure with 6' minimum walls.

This kit could be assembled by one person with only one temporary brace. The ground ring is self-supporting as soon as you fasten two panels together, and it would be easy to hold the first two in alignment. The first angled panel would require a 6-8' pole to brace it in place, but once the second angled panel is attached, the assembly is self-supporting.

Here is the Popular Mechanics article: https://www.popularmechanics.com/science/archaeology/a70277820/architectural-marvel-worlds-driest-cities/

Pavers would just be a structural base, same with laid-up bricks. Cob makes beautiful organic forms, but a cob finish on a bench would be constantly shedding dust and getting pants dirty. You need a shield or sealer, like lime plaster or tiles or an oil that strengthens cob surfaces. Bricks can be made organic as a seat, stone slabs not so much.

I wouldn't make the roof from just cob. You want solid slabs of something to cover with several inches of cob. It could be flat stones, concrete pavers, or anything strong and noncombustible.

The rate at which you can build up cob depends on its composition and wetness. More straw makes it stiffer, as does less water. More straw also makes it more insulating and less massive, so there is a tradeoff. I have found that a mix stiff enough to stand but not so stiff as to have a poor bond with a preceding dry course can rise 8"/20cm a day. For best structure and airtightness it is best to keep building so the previous course has not dried past solid stiffness when new cob is added.

Leaving some ash on the floor would certainly buffer and protect the bottom of the feed tube and burn tunnel, but I don't see how it would affect the top of the feed tube. I would be interested in finding a mechanism that would explain your experience. I only clean the ash from my J-tube every week or two and find it helpful, though I can't speak for the top as I have a steel insert that routes secondary air to the P-channel.

Very nice! Simple and effective technique. You just want all the mortised parts of a piece of furniture steamed at once and the tenoned pieces ready to go into the right places.

I believe the principal reason for insulating the plunger tube in a bell is to avoid wasting heat out the chimney - a bare metal tube would get as hot as the top of the bell. Depending on details of layout and design, it might be helpful in protecting the tube also.