Sunday, January 27, 2008

Overview

This might be a good time for an overview of the project. We're building a passive solar house with about 1800 sq ft of heated space. It will look like a traditional gable ended Maine barn with a shed addition that wraps around three sides. Simple to design. Simple to build.
In addition to living space, Michelle will have a small office on the second floor, and the kitchen will include a small bakery with a wood fired bread oven for me. If all goes as planned, we'll both be working from home.

The first floor will be a stained concrete slab (haven't decided on color yet) which will serve as a store of solar heat. Whatever the sun doesn't provide will be made up with a wood stove or, if we're ambitious, a masonry heater. A solar hot water system is going on the roof, and we're hoping to incorporate a grid tie-in solar electric system if our money doesn't run out too soon. I'm hoping that the combination of a highly insulated tight building envelope and good passive solar design will allow us to heat the house with about one cord of firewood (about $250 if I don't cut and split it myself).

I hope to start forming the foundation soon. I'll be pouring a frost protected shallow foundation. It's essentially a short frost wall (16" below grade, 8" above) that's frost protected with rigid foam insulation applied to the outside. It works because heat from inside the house works its way through the slab and protects the ground under the frost wall from freezing. This is also commonly referred to as an Alaskan slab. It's less expensive than a full frost wall and the excavation can be done will a plain old shovel or, if I'm feeling lazy, a small rented backhoe. These types of foundations have been in use in Scandinavia for decades with success. The depth of the frost wall (16" max, 12" min) below grade and the placement of the insulation is determined by how cold it gets on average. On the coast of Maine you can get by with a 12" below grade with 1" of rigid insulation applied to the outside.

I'm hoping to use little if any plywood in the construction of the house. Around here locally milled #4 pine 1x12's are less expensive than plywood and do a good job at sheathing when fastened diagonally across the studs. (The frame will be stick built with 2x6's.) Same goes for the subfloor on the second floor. If there's any place I might use plywood, it's to sheath the roof. The exterior of the building with be covered board and batten style with #4 boards as well. Very barnish. A blending of classic lines and modern building technology. To get a basic idea of what the exterior of the building will look like go to http://www.kaplanthompson.com/barndoorsopen.php

1 comment:

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