During the Pour
The guy who does my concrete formwork does a good job of stringing, squaring, and straightening the forms. To keep the sills square, I follow the forms, but I check his work with diagonal measurements. As each section of the forms is filled, I trowel the wet concrete smooth, working to grade nails set in the forms. Then I'm ready for the sills.
A section of wall is poured.
The author trowels the concrete to the correct level.
The plates — bolts and all — are then set into the wet concrete.
Handling the sills usually requires a couple of helpers. Together we set the sills in place inside the forms. Where the sills overlap at the corners, I tack the lapped corners together, squaring and straightening them carefully as I go. When I'm satisfied with the placement of the sills, I carefully push the bolts into the concrete as plumb as possible, making sure the nuts are threaded on the bolts consistently.
As the pour proceeds, the crew works quickly to position the plates.
And push the anchor bolts into the concrete.
Next I station a crew member on a transit or laser level and check the sills for level. When I've found the lowest point, I go around and thump the rest of the sills down to that level with the head of a sledge hammer. I drive a nail through the forms every few feet to hold the sills in place while the concrete cures. Occasionally, I'll need to use a brace or block to hold a sill straight.
While the concrete is still plastic, the crew finds the lowest point on the foundation, then uses a sledge to tap all the plates to that elevation.
Here the author checks the short garage-wall plates for level.
After the forms are stripped, I check the sills for square and level again. If minor adjustments are needed, I can always shim or plane them a bit. Small lateral adjustments can be made by shifting the upper sills and elongating the bolt holes slightly if necessary. But generally none of these tweaks are necessary.
The concrete tends to ride up along the sides of the sills, particularly in areas where they had to be thumped down. On the inside, this is not a problem, but on the outside, I flake off the excess concrete with a hammer claw so that the wall sheathing can be run down and nailed to the bottom plate.
The author uses a claw hammer to remove the irregular ridge of concrete along the side of the sill.
The finished result is accurately placed hold-down anchors and foundation bolts.
On the garage shown, the entire sill-layout process took me a couple of hours before the pour. (I was working alone with no distractions.) Setting and adjusting the plates during the pour took less time than just measuring and setting the bolts would have.
John Spier owns Spier Construction on Block Island, R.I., with his wife, Kerri Spier.