The hillside before we started (a favorite picnic spot)
Steps taken so far:
- We chose location because of orientation (southwest to south curving hill face) and slope (considering height over floods).
- We dug a roadway "cut-and-fill" marking the end of the cut (no building is being done on the fill portion, this is reserved for yard, garden, and roadway/access paths). This allowed for access to the site from both ends. Ultimately the south end will be access to the road and the east end will be access to the garden and barn.
- We dug pad (with 5 week hiatus when a kingfisher built a nest in a cave where a stone had fallen out) and leveled it. We came across a few deposits of clay, some of which we reserved for ceramic trials. The hill is ancient glacial till and has stones, isolated patches of sand, and patches of clay as well as a lot of mixed soil in it.
- We dug the foundation. It needed to be 4í deep for frost line, although I intend to protect most of the foundation from the frost eventually, with even insulation under the southeast side patio.
- We poured 10 yards of concrete over a frame of four rebar.
- We laid concrete block, 12" where it serves as retaining wall, 8" everywhere else (greenhouse face, exposed [insulated and stone faced] face, and those common with other rooms). We hand filed the block below obstructions (power entry, for example).
- We dug a trench behind the foundation and put down perforated drain tile (with sock) that runs all the way to the hillside on both ends. Theoretically this should not be necessary as the thermal umbrella should be dry soil, but it seemed the safer way to go. We filled the trench and backfilled to the top of the drain-tile with crushed rock gravel.
- As we laid block we sealed the outside walls and back-filled soil, walking on the fill to reach the next courses of block.
- We built forms for the three arches (two exterior windows and fireplace hearth beam) and the two flat beams (over doorways). Set frame of two bar throughout and four rebar (shaped for arches) in beams. Set some extra bar for hard connections to future walls (ties). Built in a slight slope for water drainage, hoping that if we use this as a floor the slope will not be noticeable.
- We hired a concrete pump truck and poured another 10 yards to fill all block and bond beam (including arches and door beams) monolithically.
- Had the three Pre-cast panels delivered and set on cured bond-beam. Sealed all (vertical and horizontal) joints with silicone (the driver forgot the butyl seal I had ordered). I did have to go back after a year and reseal several places.
- Winter hit and we covered the openings with plastic and set up a test greenhouse of plastic.
- Temporary roofing: We put 2 layers of 2" (each) Styrofoam sheets over the pre-cast panels, and thin OSB over that (so we could walk on it), and rubber roofing membrane over that. We held this all in place with concrete blocks. We did not seal the joint in the rubber and it did leak a little in the spring.
- I put a sheet-metal roof over the area where the mudroom will be to provide some shelter for storing materials.
- I put some sheet-metal panels around the back to keep most of the water out of the back-fill, as the thermal umbrella soil needs to be dry. This was a poor half-measure and didnít work well. Eventually the moisture helped settle the back-filled soil but it cost me a year of drying time. Thr right thing to do would have een to rent a tamper and tamp the fill, then cover to keep dry.
- I left the form wood in the two doorways and used that to set the doors, one an insulated slider that will open into the greenhouse, the other a steel-clad insulated entry door that will eventually be moved to the (not yet built) mudroom. In the window wells I framed in (we left a 5" reveal to allow for the finish stone work) and installed the low-e dual pane casement sets.
- I had glass cut to the same template that I used when building the arch forms and built dual pane fixed windows above the casements.
- Failing to decide on a permanent floor solution, we put down joists and ¾" plywood sub-flooring. I have picked up a whole bunch of scrap granite countertop material (leftovers) and am thinking about a large-piece mosaic floor in the kitchen area, as it is dropped down one step below the plywood (temporary) flooring and sits on the (sealed and sanded) native soil. The plywood was all screwed down so I can reuse it for other stuff later when we decide what kind of (and at what height) floor will be permanently installed. Quite possibly brick.
- We set three posts and a beam and out up the greenhouse exterior roof this spring. We used 2x6 joists and cattle panels in place of purlins. The fiberglass corrugations run parallel to the joists so lateral support is critical. The cattle panels provde tremendous support without blocking very much light, and provide a matrix that allowed me to silicone the fiberglass down firmly. Lifting forces in high winds could be more of a problem than snow-load, which is easier to design for.
- I've been laying up 4" block on the corners and filling with clay from the site. These 16" x 24" solid columns wil also act as theremal storage. The original plan caled for filling the center ziggurat too but we like the space for a sculture niche, or perhaps a fountain in the summer, so I've left it for now.
The foundation is poured concrete with 4 rebar. (Thanks Pete, Chai, Vu, Rachel, and Pete's Artist-in-Residence)
We sealed the concrete, then laid down foil, then 2" of 2# beadboard, then repeated the foil and bead board two more times. Temporarily this is covered with OSB and rubber roofing, but ultimately it will be cast concrete.