A Shop for Dan #6: Foundation Poured!

Haven’t posted here for a while, but things are starting to come together.

In August, I started digging out the foundation for my shop. Although the dirt underneath the slab that I cut out was actually quite workable, the clay underneath the lawn portion of my potential shop was rock hard, and while jumping on a shovel I managed to slip and topple into a wheelbarrow handle, resulting in a broken rib and an emergency room visit.

Word to the wise: Should you find yourself with a broken rib, consider carefully painkillers. Vicodin made me think I was hilarious, and laughter was the wrong thing to do with a broken rib.

Anyway, after a long healing period, back in September I finished digging out the foundation for my shop, The structure is a thickened edge slabs, but the “thickened edge” really ends up being solid footings, < 20” down on undisturbed dirt, and >= 18” thick. The thickness was chosen because the living roof makes this really heavy, and when I did the seismic calculations, worst case for soil was about 12”. I talked with my engineer, and he said I could get away with 12”, but I decided that a few extra bucks for concrete was worth the margin for error, especially since trying to do this in a single pour meant that I’d have a bit of torsion on the bars:

There was then a short delay while I negotiated a few things with my plans with the city, and then I ran rebar, 12” centers, tied on every crossing, with > 3’ overlaps on all joints, tied at least 4x, with a #2 copper wire to a Ufer ground. The anchors are 24” for the shear wall ends on the corners, 12” J-bolts at 34” or less for the sill plates generally.

My neighbor’s a contractor, and I know nothing about running concrete, so I hired him for help in my pour, which happened Friday:

Entries on my blog about this:

• September 25: Workshop Foundation Progress
• October 24: Rebar and Forms
• October 28: Foundation Pour

My neighbor is Loren, of Blue Moon Building and Landscaping in Petaluma, Loren is an awesome neighbor, helped me out by looking at my forms and rebar and making suggestions while I put that in place, and then did the pour and finishing. In fact, the one time he tried to involve me in the process, ‘cause I was standing around looking silly, he handed me a rake and said “watch behind us while we’re screeding this in case the concrete gets too high, you can smooth stuff out”, and Manny, the pump operator, said “you only need that if the pumper makes a mistake. Stand aside.” Sure enough, I was superfluous.

The pump provider was Manny, of Five Stars Pumping in Fairfield (I think). He was awesome and affordable and Loren had worked with him before.

The concrete came from Shamrock Materials, who have a plant in Petaluma just a few minutes from my house.

-- Dan Lyke, Petaluma California, http://www.flutterby.net/