http://mindismoving.org/hexayurt/

The Hexayurt is a super minimal building: 160 square feet, made mostly from whole 4' x 8' sheets of plywood or other appropriate materials. The walls are made from two 4'x8' sheets side by side, forming an 8' square. The roof is made from 4'x8' sheets cut along the diagonal to form triangles 8' high and 8' wide at the base. This geometry was designed for use in refugee shelters but would scale to a microbuilding very well.

In a permanent building, one would do standard 2"x6" framing and use conventional building and insulation. techniques. Beams would be cut using a compound miter saw so the angles formed by the intersecting pieces would be precisely machined, which makes for a very fast, very simple assembly. Hardipanel (a cement board product) coated with an elastomer would be the tool of choice for the walls and roof, I think.

It might also be possible to do a stressed skin plywood approach and then shingle it, but that could well suck.

The design could also be "stretched" - take a Hexayurt and cut it in half. Then insert additional 8'x8' "panels" to move it from being a standard hexagon to an elongated one. This would roughly double the available floor space for only slightly more building materials. Add a composting toilet and you have a semi-autonomous building.

http://en.wikipedia.org/wiki/Autonomous_building


COST ESTIMATES

$360 - 18 sheets of facing material, at $20 per sheet

$800 - Insulated Concrete Slab foundation (nominally $5 per square foot) - but could be posts instead. Insulated concrete slab would be preferred, however, to give the building some thermal mass.

$360 - 36 two-by-six 8' long for framing

$200 - elastomeric skin product (see the sealents by AFM - the people who make SafeCoat paints)

$300 - guess at costs for insulation

$1000 - windows, doors, trim

- so we're talking around $3000 of materials before we get into interior fixtures and so on. If the design was to have a sleeping loft, there would be a cost associated with the stairs and the support system for that loft also.


Intellectual Property
The Hexayurt design is in the Public Domain. It was placed in the public domain after Hurricane Katerina.