Hi folks, I posted this in the natural building forum the other day but I realized that it aligns more neatly with questions about framing, since many of my other considerations are dependent upon answering that question so I moved it over here.
I've been tossing around some ideas for an outbuilding on an urban homestead in Detroit. We're heading into the new season and we have a serious need for a multifunctional building near the house. In spring and winter it will provide a small workspace; in summer and fall it can be used for processing and curing some small grains and other crops; year-round it can be used for storing livestock supplies, building materials, and firewood. There's still a month or so of inclement weather before I need to break ground so I'm hoping to get a solid working idea, draft it up, and gather materials before that time.
I'll try and get a rough blueprint of the building site uploaded, but the building space needs to be located sightly to the northwest of my house. That provides close access from the barn to the livestock and fields, as well as from the house to livestock supplies, processed crops, and building materials. The backyard is to the west of the house and the farm area is to the north. Our prevailing wind comes out of the southwest, so I was thinking of using a single-slope roof (http://cdn.timberframehq.com/wp-content/uploads/2012/05/timber-frame-barn1.jpg something along those lines) opening to the north. The lower wall will back up into the yard and there I'll build a small canopy for firewood storage. Building code in the city doesn't require a permit for non-residential buildings of less than 120sq. ft., and I don't realistically need much more room than that to start out. Rainwater will likely be redirected to a storage tank to the side of the shed.
I have access to a large variety of supplies from buildings slated for demolition or already collapsed in the surrounding area. A general list would be:
2x's can be used for the frame; "urbanite" stone for foundation; tires as either foundation or infill; metal roofing for... roofing; clay and sand for cob or plaster. Hopefully that's not too much context to bore any readers, but it's basic background for what I have to work with in the area. I would prefer to visit-box-stores/buy as little as possible for obvious reasons. I've done my research on foundations and have a good idea of how either a rubble trench, stone plinths, or buried posts (maybe charred?) with stone packed around them might work out.
My primary issue is the frame. Though the materials I have at hand are all fairly conventional, I would like to gain further practical knowledge of natural building, particularly timber framing and cobbing, as my understandings so far are almost entirely theoretical and based on reading/online research. The picture/sketch I linked to as an example above is obviously a timber frame. But I have no timbers. Given the planned functions of the shed/barn I would like it to be open at the front, potentially even on two sides. I had been thinking of essentially "tying" together sets of 2x6's and 2x8's into 4x6 and 4x8 posts and beams to build the front of the frame, and then stick framing the rest. But then I started considering using my faux "posts" and "beams" to frame out the entire structure save the rafters. I know some people do this for top and bottom plates on walls but is this just creating unnecessary work for myself? Is there any advantage to the idea? It seems like whichever frame I go with I can more-or-less adapt the infill to the structure as long as I plan the foundation will and the roof will remain relatively unchanged, just rafters running from the lower to the higher wall.
Is there yet another solution I've overlooked? Thus far I've passed on the idea of using cob, strawbales, or tires as load-bearing walls because of the amount of time it will take to put them up. I have eventual plans for a greenhouse and larger barn using some of those materials as structural elements once I have this rough workspace set up.