02-28-2011, 04:26 AM
quote:
Originally posted by dobanion
All the rebar and the difficulty of wrapping/bending/wiring it was what turned me off of monolithic domes previously. This is fantastic.
And, you can use the same airform over and over, when built "Ecoshell" style like above.
Not to mention that reels of basalt roving are a lot easier to ship/transport/handle than 20' long sections of rebar. And the "spatter" technique of hand troweling makes it practical for an owner/builder to build an Ecoshell without needing a concrete pump.
A little "napkin calculation" shows the materials for a 20' diameter, 320 sq. ft. dome to be about $1,500. That's hard to beat.
The prime issue, of course, is the cost of the airform. That's gonna cost about $5,000 delivered in Hawai'i, plus you need 2 inflation fans and controls (for redundancy - inflation failure for even a short time can ruin the project.) plus the power to run them non-stop for a week or more.
And while it is true that the Ecoshell airforms
can be reused many times, as they have done in India, for the owner/builder wanting a single use, there are no good options. To me, this is the biggest weakness to the Monolithic approach. A rental option would solve this, but they don't seem interested.
So, I am exploring alternate approaches that would allow forming a thin-shell reinforced concrete structure over some other temporary support. I'd like to find a way to be able to build these off the grid, by hand, without the use of any power supply.