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Digging the Foundation Part 1

April 10, 2007

I staked out the building by driving stakes into the ground where the four corners would be. I made a big 3-4-5 right triangle out of scrap 1x4's to check for square at the corners:

As I was doing this, a carpenter friend stopped by and helped set up the batter boards that hold the mason's line away from the proposed foundation. He squared the lines by measuring a bigger right triangle, marking it on the strings with a marker. Here is the outline of the building, sized and squared up.

The building will sit on a cinderblock wall foundation. The cinderblocks will rest on 18" wide, 8" high concrete footings. These must be 36" deep to be below the frost line. I thought we could dig the footing trenches with shovels, first using a rototiller to loosen the soil. A few calculations showed that we would have to move over 20 cubic yards of earth. The earth would have to be moved out of the trench and away from it to allow room to work in the trench. Decision: rent a backhoe.

The backhoe arrived on a Tuesday morning. By the time it arrived, I had painted lines on the ground. I used a plumb bob to position a mason's line on the ground:

Then I used a marked board to spray paint a line 5" from the mason's line on the outside and 13" from the line on the inside. This marks a trench in which 8" blocks will sit with 5" on either side.

I took away the mason's line. Ready, dig:

I requested a backhoe with a 16" wide bucket. This digs an 18" wide trench when operated by a novice like me :-)

I dig. Click on the picture to see a wmv movie:

Here is the 40 foot trench. Not too bad for my first try. The depth is 3 feet in some places. It will have to be cleaned up with a flat shovel.

Now comes the snafu. While digging the next leg of the foundation, I uncovered a sewer pipe. With the help of my brother, we probed the ground with backhoe and other tools. We found that the pipe feeds an auxilliary drain field that lies across the area where I had intended to build the garage. There are many words to describe how I felt at this discovery, and there are some words I may have uttered as the location and extent of the drain field became evident. I chalked it up to experience and education. We decided on a new location and I dug at the closest point to the drain field to see if the ground was dry there. It was, so I had an option to propose to the township zoning board. In the meantime, I had to fill in the trench I had already dug :-(

Next: Clearing the Land