Updated: Jan 1, 2019
For anyone who wants to grow plants most of the year, a greenhouse is a basic requirement. Plants get a head start earlier in the season and growing can extend later on into the season. Not to mention, the deer can't open the door and eat all my plants (that will be the day I quit farming). We built most of this just before Thorin left in November, as we were behind schedule but blessed with many dry days.
We were particularly interested in building a passive solar greenhouse (without any heat source) cleverly constructed to capture and store the heat from the day. We designed plans with dimensions of 16x24', which fit nicely against the carport. Most of the surfaces are transparent to collect light (which, in the PNW winters, is notoriously scare) and only the north wall is insulated (because here the winters actually aren't that cold). In other climates, where it gets colder but there is more sun, it would make more sense to have a lot more insulation and less glazing (transparency). To store and retain heat we will use rain barrels, which will also collect and disperse water. It's always smart to have components that are multi-functional such that your system is both efficient and synergistic.
Because we are very interested in natural building, we decided to incorporate some unique #Earthship techniques (we love Earthships because they beautifully integrate sustainable building, permaculture, and art). This mostly involved building a tire stem wall with pounded dirt. The tires, like the rain barrels, also serve as a heat sink to capture and retain the heat during the day. You probably don't realize how much dirt it takes to fill one tire (with a sledgehammer, no less), and then make it level with all the other ones. Believe me when I say it took four full wheelbarrows full of hard @ss clay to fill one tire. There were over fifty tires, and that was only for one and a half courses of tires (don't ask me how they build whole houses with these). That took us a couple of weeks in itself, but we finally did it and bought ourselves a cold beer afterwards.
Some may consider tires to be a poor choice in material, citing the potential for toxic pollutants to leach into the environment. They are a sad reality of our human occupation; a ubiquitous resource that, once used, contributes to the contamination and degradation of our beautiful habitat. Not only is it imperative that we design new materials that are more sustainable, but we should also consider healthier ways to dispose of those that are not (like most petroleum products). I think that using tires as building materials is a relatively safe way to "dispose" of them, especially when they are encased in plaster. The tire "bricks" are super solid, fireproof, insect proof, and modulate the temperature. Before you frown upon tires, consider some of the other alternatives: mountains of exposed tires leaching into the waterways or mountains of burning tires spewing toxic fumes into the atmosphere. Fortunately, I am confident that microbes will soon adapt to metabolize plastics into harmless organics, as they are a huge accumulated carbon resource waiting to be utilized. Nature never wastes, and neither should we.
As usual, we tried to use as many recycled and local materials as possible. We got the tires from our local LeSchwab, who, because they must pay to dispose of them, eagerly gave them away and helped us load however many we wanted. The three 7x7' windows were salvaged from a friend (who actually gave us five total!). These are big boys and had to be very carefully lifted in. Luckily we had great helpers and no one had their limbs cut off. We received nice thick plastic from our wonderful neighbors and harvested the huge rafters from the old barn down the road. I bought some hardware and the door at one of my favorite stores, Restore. We still had to buy all of the lumber to frame it, the plywood for the north wall, and the polycarbonate roofing, all totaling approximately $1500.
Of course, there is still much to do. Once the weather dries out again, we will make super fun #bottlewalls in the spaces adjacent to the doors and windows (if you find any of cool colored bottles (blue, purple, red, etc.) you know where to send them). We will also plaster over the tires and install our rain barrels and insulation. We may even build a rocket mass heater bench! If any of these activities sounds fun or interesting to you, please contact me! We often have work parties that involve rewarding ourselves with pizza from the cob oven.