The Pad

In order to get a permit, I had to give the county a picture of my intended buildings with the dimensions of the offsets from the property line noted. When I was little, I noticed by the way my dad parked his car at the mall that the more space you have for something, the longer it takes you to figure out where you want it to go. With about 80 acres of land and roughly an 8 acre sub-plot on which to put this building and one other, the conversation on where to put this first building had been going on for about a year.

But when I showed up on Saturday morning to see a backhoe sitting up at the top of the hill, and Jerron down by the bus with a skid-steer, that was probably when I realized that we were about to make the final decision and the bullshitting about which direction the sun came from and where the best views would be was over. Chris gave me a crash course on backhoe operation, noting that the shifter felt like it was dangling off and about to separate totally, and I drove to the bottom of the hill and parked the beast.

The goal for the weekend was to create a 50'x60' rectangle with sides aligned north, south, east and west where the topsoil was removed and stacked to the south. First, we marked off a 40'x48' irregular quadrilateral with four concrete stakes. We iteratively measured the diagonals, moving the corners slightly until the diagonals were equal and the walls were the right length. Satisfied with the footprint, we traced it with orange spraypaint on the ground. Then we pulled up the stakes and cleared the topsoil and organic matter from the ground.

For this task, Chris would stand on the pad and direct Jerron who used the backhoe to remove or replace dirt. A pattern emerged which pretty well summarizes the jobsite roles:

Chris: foreman, points a lot, gives short simple instructions and makes sure everything is perfectly square, or perfectly level, or exactly the right length. Looks at stuff a lot. As soon as he does not like what he sees, things are coming apart, quickly. Has practical experience doing this stuff, which is absolutely necessary (since I don't.)

Jerron: heavy equipment operator, force of nature. Understands all hand signals; can interface with equipment rental salesmen, concrete truck drivers, rednecks. Either can operate the device that you need to get the job done, or doesn't realize that the job is human-impossible and does it anyway. A wealth of prctical information doing things differently from how Chris does them, and thus a crucial counterpoint to all procedural design.

Me: if Chris can make the instructions simple enough, and if it's not so heavy that a person cannot possible lift it (see above), I'm on it.

Clearing the pad was cake, mostly because I wasn't really doing much. It was 95 degrees and there's no shade out there except for the bus, so I suppose that's something, and I wore a hole in my thumb with a shovel, but it's really, really hard to feel like you accomplished anything when there's a backhoe working with you.

When the rectangle was clear and mostly flat, we replaced our corners and then transferred the lines to batter boards. Since we were about to dig trenches right where the corner stakes were pounded into the ground, we needed to replace the lines that ran to the corners with lines that ran past the corners, where they tied up to precisely placed nails on the batter boards.

The Frostwall Trench

Once complete, we took to the task of digging a frost wall trench in the dimensions of the building, 48'(east and west)x40'(north and south). To accomplish this, we used a linear ditchdigging attachment for a skid-steer. Basically we're dealing with a big fucking chainsaw on a Bobcat. Hellaciously awesome. I want to saw a car in half with one, but Chris does not allow it: we only have good cars and the bus onsite. Jerron offers to flag down a car on the road and take it; this plan is also shot down. We get to the digging. The line from the batter board strings is transferred laterally to provide a guide line, and Jerron keeps the skid-steer's left wheel 1/4-1/2" away from the line while a ten foot boom with a rotating chain saws through the ground. Now I can see why he annihilates all video games; in the blazing sun, under severe vibration, he can keep several thousand pounds of rotating machinery on a dime. I tried to drive the Bobcat and couldn't really even get it to go straight. It is definitely not a precision machine; the joysticks are both loose and there's a lot of slop when I try to drive it, but Jerron finds the sweet spot.

watch Jerron run the trencher

The point of a frost wall is that when the ground freezes, it only freezes down to a certain depth; below that, it jsut gets really cold, but not cold enough. Where it actually freezes, the moisture expands as it crystallizes and the ground moves up. If you are building a building with a concrete floor full of tubes for radiant heating, you do not want to build that slab right on the raw surface of the earth, because around the edges, the ground beneath the slab will freeze and the slab will crack around the edge. Your tubes will tear. Warm water will go everywhere. Everything will be ruined.

Instead, run a concrete (highly insulative) wall vertically down below the frost line around the perimeter of the slab. (Your local building inspector can give you information regarding where your frost line is.) Put the slab on top of the frost wall, and now the ground under the slab will be protected from freezing, and when the ground outside freezes and thaws (and thus moves up and down) it will do so around your foundation, not under it.

Additionally, in two locations there are schedule 40 PVC pipes sticking out of the building: one for sewage egress and one for freshwater ingress. Both pipes need to pass through the frostwall al low as possible to minimize stress on the pipes.


With major digging operations complete, we moved on to making sure that the pad inside the trench was perfectly level. This was an iterative process that involved a lot of digging in the middle of the night because the laser that we were using to judge elevation is weaker than you could possibly imagine. And because the sun is so fucking hot that working during the day in June is perfectly, perfectly insane. I never want to see a shovel ever again, and I would give anything to own a skid steer.

There was also a good amount of dirt that must be removed from the frostwall trench; most of it was dirt that has fallen back into the trenches where the walls meet and the trencher came by twice. An animal (prairie dog, most likely) dug through the side of the trench and left a gigantic pile. Let him have his fun; soon there will be concrete there! J played a cameo role as we leveled the pad and the frostwall; her cross-country drive put her in Wyoming for a week during the hottest, dirtiest work and she did not complain nearly as much as I did.