Notes from Windward: #58
Working on the dining hall
Jerry takes on the dining hall
There are many factors that go into determining what projects we're working on at any given time. The weather is a big one. Projects involving digging are best done in the spring when the ground is damp and soft. Other projects, like moving a 5 ton steel shipping container, need to be done late in the summer or early fall when the ground is dry and hard. Once the snow comes, it's time to put another log on the fire, crank up the computer and work on plans for next year's construction.
Some projects limp along until the right person arrives, which brings us to the story of Jerry and the dining hall. Lately we've been giving thought to our visitor's policy, and have decided to try something more along the lines of what Twin Oaks does, i.e. encourage interested people to come and visit for a month. That period of time gives a new person a reasonable chance to learn about what we do, and allows them to actually get involved in the day to day life of the community.
Part of the perimeter foundation
Jerry is the first person to take advantage of the new program, coming up from Phoenix to learn something about Windward and to test out the white water on the Klickitat and White Salmon rivers. After his first week, he came to the conclusion that one of the primary bottlenecks to our growth was the kitchen. We needed bigger and better facilities where we could fit more people around the table and where groups could better gather in the evenings to socialize.
We agreed with him completely. What was refreshingly different was that Jerry was ready and willing to do something about it. We get lots of visitors who are happy to tell us how we should do things, but not many who are willing to pick up a shovel and help.
The main dining hall has been under construction for a long time. When finished, it will be a long earth-sheltered structure some 58 feet long and 18 feet wide running east to west. More specificly, the central area is 30'x18', flanked by a 10'x14' room at each end. The eastern room will be a "mud room" where people take off their boots and hang their coats, while the western room will be a combination pantry/dishwashing area.
To view a drawing of the cement work on the dining hall, Click Here
Tying rebar in place
The design provides lots of window space to the south to let in light and heat, and to the north, there's a high earth-sheltered retaining wall. When complete, we'll backfill the north side to the point where you could easily walk onto the roof, something which I expect the goats will find most interesting.
The advantage of earth sheltering is that it creates a thermal mass which moderates the temperature inside the structure. It absorbs heat in summer, and it keeps the cold, frozen north side of a building from acting as a heat sink in winter.
The downside is that the building requires a substantial waterproof retaining wall to hold back all that soil. The building code requires at least a six inch steel reinforced concrete wall, but since we're constantly learning as we go, we decided to go with a more sturdy eight inch wall. One reason we get along well with the building inspector is that we use the code as a minimum standard, and don't hesitate to go "better than code" where appropriate.
The first of the roof joists go up
One key to sustainable living is good planning. It isn't that hard to incorporate renewable energy into the community during initial construction, especially when compared with how difficult it is to go back and retrofit things. The roof of the dining hall is an example. The orientation and angle of the roof were chosen so that the surface of the roof is an optimal solar receptor for this latitude.
This will allow us to mount solar panels flat on the roof. Not only will that be more secure, it's much more aestheticly appealing than mounting strategies which project away from the surface of the roof at odd angles. You've probably seen thermal solar panels on the roof of some houses, and can appreciate that however practical they might be, they don't add anything to the aesthetics of the house.
Another system that needs to be built in at this point is the grease trap. Since we'll be processing a lot of food and doing a lot of dishes, the drain system needs to separate out grease before the waste water enters the septic system. Septic tank bacteria don't handle grease well at all, so it's important to not clog the tank. While it's still a yucky chore to periodicly clean out the grease trap, it's far better than having to deal with a malfunctioning septic system.
Starting a new section of retaining wall
The retaining wall is created by pouring concrete into wooden forms. After the concrete sets, we remove the forms and reassemble them further up the wall for the next pour. By doing this bootstrap process, we're able to pour a six foot wall in five pours.
This type of building is called a pole-barn because the weight of the roof is supported by heavy poles that rise up from thick concrete pads 3' down in the ground. The advantage of this type of construction is that the walls don't bear any weight. All they have to do is hold themselves up, so you don't have the complex header work when the walls are holding up the roof. One result is that these buildings are very flexible in function. Since the walls aren't load bearing, if you later decide that you want to knock out an interior wall and "rearrange" the layout, there's no problem because the wall isn't holding up anything but itself. In standard "stick construction," you can't do that.
Pole barns are simpler to put up (a good thing when the crew is learning as it goes), and they're also about as earthquake proof as buildings come. Personally, I like their similarity to timber framing, a technique that I'm looking forward to working with later on. But for right now, especially for our basic buildings, pole barns are the way to go.
Pouring the base on part of the perimeter foundation
In addition to the retaining wall, there were the perimeter foundations to put in. Since the walls don't hold up the roof, the foundation that holds up the walls doesn't have to be very substantial. In fact, the biggest concern is that it gets below the frost line. By digging the foundation by hand, it's possible to excavate in such a way that it isn't necessary to construct a form. Instead, a trench is dug in undisturbed earth, rebar is put in place, and concrete is poured in to create the footing.
The point about undisturbed earth has to do with the need to insure that the concrete is placed on compacted soil. If you were to backfill in order to save on the amount of concrete, over time, that soil could compact and create a weak spot under the footing. That could cause the footing to break and the wall to droop or shift. It's better to be careful, and do it right the first time than try to backfill a footing trench.
Tamping a timber with 3/4 minus
However, there are times when it is necessary to backfill. An example is the hole around the poles that make up a pole barn. The hole is dug oversize because of the need to put a large concrete pad under the pole. That way the load on the 36 square inch pole is transferred to the 1,000 square inch pad. Otherwise the weight of a heavy snowfall could drive the pole down into the ground.and wreck the building.
Once the pad's been poured and the pole is positioned in place, you need to backfill the hole. If you use regular soil, it will compact over time and not be very secure. Even worse, the soil will tend to stay damp and thereby increase the chance that bacteria will attack the pole and cause rot. Even though the pole has been treated and is certified for use in this manner, it's still a good idea to do what you can to see that the wood stays as dry as possible. By backfilling with "3/4 minus," any water that is drawn to this area will drain away from the wood. It's sort of like creating a mini-drainfield for each pole.
A yard of 3/4 minus
"3/4 minus" is rock that's been put through a crusher to break it down into pieces which will fit through a 3/4 inch grate. What comes out runs the gamut from small rocks down to sand sized particles, with the result that it has the capacity to form a solid mass with only a modest amount of compaction. It's different from gravel in that it's sharp and angular (from the crushing process) instead of round and smooth. Gravel comes from old stream beds and shows the effect of having been tumbled. It's the sharp edges of the crushed rock that gives it such compacted strength.
The other thing that the perimeter foundations will do is provide support for the concrete slab that will form the floor of the dining hall. There's a lot of clay in our soil, so it tends to swell in the wet season, and shrink in the dry. Without a solid anchor for the floor slab, it would be subject to bucking or settling with the seasons. By tying the slab into the foundation, we'll eliminate much of that.
Continued in Part II
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