From CAST architecture
This backyard cottage is a compact 550 square-foot, two-story studio that includes a loft-bedroom, full kitchen, and bathroom. Use of a standing-seam metal roof, energy efficient lighting, super insulated building envelope and efficient heating make long-term sustainability a design focus.
Recycled materials, as a form of sustainability was also a central idea to the design. The radiant-heat concrete floors are made of fly-ash a by-product of burning coal as a form of recycling. The exterior walls are a combination of twin inches of rigid insulation and five and a half inches of cotton insulation, made from recycled blue jeans. Reclaimed fir was used for structural beams, posts and the stairs as well as reclaimed claw-foot tube in the bathroom.
Creativity with traditional material usage was also implemented with galvanized electrical conduit, at a cost of only $1.65 for a section, as the loft railing.