Talk:Air-formed domes

Closely related page: http://openfarmtech.org/wiki/Monolithic_Dome, perhaps we can merge them. Basic difference: binishells= concrete first, then inflate monolithic= inflate, then "shotcrete" --Rasmus

Binishells seem much cheaper. I have no idea why. --Conor 13:44, 26 February 2011 (PST)

Doesn't make obvious sense. Monolithic has brought down the cost of the ecoshell to bare bones materials cost. And now with basalt fibers one of the significant cost items (steel rebar) is eliminated. The inflatable form can be reused 100 times in both concepts. --Rasmus

I just saw the Youtube link you posted on the page Air-formed_domes. The Binishell appears to require not only two membranes (a major cost item, even when reusable) but also a particular kind of steel spring. --Rasmus

The conventional wisdom on monolithic dome websites and forums is that they cost the same or a little more than conventional houses, and you make the money back in heating and repair costs. Examples: [1][2][3]. Frankly, I think this is determined more by business reasons than technological ones. They could be very, very cheap if open-sourced.--Conor 07:57, 27 February 2011 (PST)

This is true when they are built by Monolithic. MDI typically makes a custom airform which later stays with the dome on a permanent basis, to protect it from rain. This obviously adds greatly to the cost. Also, customers building such a dome often have their own very specific ideas about the desired shape and features of the dome. If it were more standardized, this type of thin-shell concrete should be far less expensive than post-and-beam construction. One big obstacle in the past has been that certain industries hate concrete domes (construction/cement industry because domes last forever and oil industry because they are so energy efficient). --Rasmus 14:02, 27 February 2011 (PST)

I'd thought the airforms were made from plastic, but it says here they're actually waterproof fabric: PVC-coated nylon or polyester. So the technology comes down to

1. How to make a fabric airform of the desired shape.
2. Stucco sprayer
3. Foam insulation

Yes, and I might add: stucco sprayer is not a technical problem (compressed air + OS sprayer and we're set). Insulation does not have to be by foam, can be more eco-friendly biological materials. In Monolithic's version of the technology, the airform has two functions: 1.) form during construction and 2.) to keep out water.

And a more general comment is that an alternative to poured concrete domes exists in domes from CEB tiles, which avoid steel and airform, is much better in terms of carbon emissions and (likely) cost, but is more labor intensive.--Rasmus 07:36, 4 March 2011 (PST)