The OSB on the ceiling was sanded clean, eliminating stamped information, and will be left exposed. Trusses were added to bolster the strength of the SIPs. They vary slightly in depth to reflect different loading conditions. The arched bottoms follow the top line of the curved south window wall. This creates an illusion that the ceiling is bowed downward in the center where it intersects that wall.

The curved walls, and a couple of adjacent, small straight walls were made of AAC block. Much lighter than CMUs, much more insulating, and producing about 10% of the carbon, these blocks require a different method of construction. For a crew who had never worked with these before, the results were good, if not excellent. The difficult challenge is to tackle "old habits die hard", since this material requires more precision in initial leveling and precision in the application of the thin-set mortar. When learned, it actually requires very little leveling, if any, as the walls go up. A special band saw with a sealed motor able to cut 2' vertically is essential. The blade is carbide tipped, and the table slides the material through the blade, shutting off the saw automatically at the end of the cut.

To make a column, take a 2' long 8"x8" block, stand it up on the band saw, and slice it in half. Then make 2 vertical notches, and pry out the center, making a U shaped section. Repeat this with the other half, and then glue them together, creating a hollow column. Make an identical piece, and glue the ends together to make a four foot column, place it over the rebar, screw on 2 temporary braces to plumb it, and fill with 3/8" maximum aggregate grout. Should you need to get your hand inside to tie off a bar, you can cut a small access square out of a side, using a stiff carbide reciprocating saw blade, and glue it back in before grouting. If you need to pin 2 blocks together, because the center of the column is a void, holes drilled slightly wider and longer than the rebar pin can be filled with thin-set and then joined (center photo above.) An expansion joint which would allow movement laterally in only one direction, was easily made between the SIPs and the AAC (above right). The 3 bolts can slide into the holes drilled in the wood, allowing some movement. The separation is foam which can compress. After the block was grouted, the remainder of the space between the 2 materials was filled with sprayed polyurethane. Because the AAC is principally air bubbles, it has very little thermal movement relative to most other building materials. In warm climates, like Arizona, there should always be a slip joint between the footing masonry (concrete, or CMUs) and the AAC. In Santa Fe, this is not necessary.

The above detail shows the footing, sub-floor slab, SIPs, AAC sheathing, and various insulation locations. Below, the slab has 4" of extruded polystyrene (R20) under it, and a grid of 1/2" diameter rebar's 1' O. C. This slab is the bottom layer of a thermal bed fed by the solar wall.

AAC Details
Below are sketch-up drawings of the AAC work for the curved walls

Pieces of AAC can be carved very easily to make arches, curved elements, small add-ons, special bond-beams, and even forms for concrete Vierendeel trusses. Using 3d computer programs to model individual pieces, with all their dimensions, can be very helpful in such sculptural endeavors. Above are 2 views of a curved arched bond beam for the south window wall. Below are a series of drawings showing progress layers of the chimney, topped by a barbecue pit.