Notes from Windward: #58
The Fourteenth Pier
Finney trailer gets a foundation
Progress comes in chunks around here. A project will sit waiting for the right weather or needed materials, and then when conditions are right, it'll spurt ahead. Finney trailer is a good case in point. The Aesthetic Committee (usually consisting of all the women on site at the time) selected a beautiful but challenging location for this trailer, and while I'll have to admit that the site selected is lovely, Bob and I had some concerns about the slope of the ground.
In late winter and early spring, our ground can become waterlogged, and when that happens, its load bearing capacity falls off rapidly. So in order to insure that the trailer's foundation would take the weight no matter how soft the soil became, we elected to put in large-foundation piers, and lots of them.
Fourteen to be exact.
Each pier rests on a two-foot square base of reinforced concrete. These were poured in place over undisturbed earth, and will serve to spread out the load over a four square foot area. The piers themselves were constructed from heavy-duty cinderblocks, which were then filled with concrete. Since the rebar in the base extends up into the piers, the pier and base function as an integrated unit.
Most of the piers were straightforward, but one involved removing an oak stump and another straddled the sewer line, so some modifications had to be made. With a project of this size, there's always something to fiddle with. In addition to the enlarged base, we also increased the number of piers. With seven on each side, that makes for a lot of support.
Using a water level
Once the last pier was in place and topped off with cement, it was time to start to transfer the load from the temporary cribs to the actual piers. Moving something this big, especially when it's such a distance off the ground, is a sensitive matter. If we weren't concerned enough, the fellow who delivers our rock and sand pointed out that he was the one who found the fellow up on high prairie who got crushed to death when a mobile home fell off the blocks. Stories like that are a quick reminder to take it easy, be careful, and most of all, do it right.
The first task when leveling a trailer involves figuring out just where level is. Given the distance involved, more than 60 feet, neither a standard level or even a string level would tell us what we needed to know. Instead, we drew on a technology as old as the pyramids - the water level.
The modern version involves two attachments that go on the ends of a garden hose. By hooking enough lengths of hose together, you can accurately measure differences in elevation over hundreds of feet. The way it works is that since water seeks its own level, all you have to do is elevate the lower end until you have water showing in both ends, and then mark that point. It really is a remarkably simple technique, especially when you consider how accurate it is.
Once we had the ends of the trailer level, it was just a matter of sighting along the frame. We used hydraulic jacks to lift the frame, and then insert wooden shims that would hold the frame in a level position. It takes some fiddling to get the trailer level from front to back and side to side, but after a bit of going back and forth, it was close enough.
Sand and rock
While we had hoped to get more done on Finney trailer this year, it looks like this will wrap up work for the winter. They're saying that this will be an "El Nino" winter, and therefore unusually warm and dry. If that should come to pass (we're skeptical about such things), then we'll be back to dig and pour the foundation for Finney's two extensions.
And if the weather holds us back, then we'll be ready to go in the spring. Either way, we're planning on having Finney online by next year. We've already got the rock and sand stockpiled and ready to go.
stockpiled for next year
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