Layout at the Foundation
After the foundation forms are in place, I lay out the
centerline of every door and window opening directly on the
formwork. Next, I figure backwards and mark the exact locations
of rough openings, trimmers, and posts. We work off the actual,
not nominal, post sizes to determine the setback (offset
distance from the edge of the actual post) for the centerline
of the hold-down bolt. For example, the hold-down shown in
Figure 2, uses a 7/8-inch anchor bolt (the hole is drilled 1/16
inch larger), and has a centerline 21/16 inches from the face
of the post.
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| Figure
2. Bolts for hold-downs like the type in the
photo (top left), have to be precisely located with
respect to the framing when the foundation is poured,
as do post anchors (top right). Embedded straps (bottom
left) are somewhat more forgiving. |
It’s possible to simply measure the distances, but
often the bolts are on site before the rest of the hardware is
delivered, so to be accurate we look up the centerline
dimension of each style and size of hold-down in the hardware
catalog.