This sounds like the best idea yet, and seems fairly easy. Woudn't a ton of concrete like that would be pretty expensive, though? I haven't worked on my idea much lately, but I still think it could work. (the one where I was experimenting with various 'straw & string' constructions. The main problem I'm having is with the joints between the straws, I think there needs to be spheres between them of some sort to keep them spaced. I think if a metal framework could be made, then one could cover it tightly and either pour concrete on it in layers, or put some other material around it. Maybe even dirt would work, but it seems like that would wash away pretty fast with no plant roots throughout. Are there any other ways to successfully cover these domes other than concrete? Would even piling a bunch of junk and crap, old tires etc on top of it, then pouring concrete on top work? (hence using less concrete, just enough to hold all the junk together--only 1 application needed)
Instead of making solid concrete domes at high expense, what if you could make your dome framework (or dirt hill to be dug out later), but then gather as much junk and garbage as possible to pack around the outside. Once it looks like Sanford & Sons junkyard, you could then pour concrete swirls on the top--connecting all the junk together into a solid peice but using a whole lot less concrete. Does the dome have to be pretty? I know slick and aerodynamic is ideal, but maybe it would be solid enough anyhow. The only major problem I see is waterproofing, you might at least need a thin layer of concrete before you start pileing trash on top, or something.
Offered by Joe.