O
O C- On Center- The measurement of spacing
for studs, rafters, and joists in a building from the
center of one member to the center of the next.
Oakum- Loose hemp or jute fiber that's impregnated with tar
or pitch and used to caulk large seams or for packing
plumbing pipe joints
Open
hole inspection- When an engineer (or municipal
inspector) inspects the open excavation and examines
the earth to determine the type of foundation (caisson,
footer, wall on ground, etc.) that should be installed
in the hole.
Oriented
Strand Board or OSB- A manufactured 4' X 8' wood
panel made out of 1"- 2" wood chips and glue.
Often used as a substitute for plywood.
Outrigger- An extension of a rafter beyond the wall line. Usually
a smaller member nailed to a larger rafter to form a
cornice or roof overhang.
Outside
corner- The point at which two walls form an
external angle, one you usually can walk around.
Overhang- Outward projecting eave-soffit area of a roof; the part
of the roof that hangs out or over the outside wall.
See also Cornice.