Glossary

Open valley: Method of valley construction in which shingles on both sides of the valley are trimmed along a chalk line snapped on each side of the valley. Shingles do not extend across the valley. Valley flashing is exposed.

One piece toilet: A toilet in which the tank and bowl are manufactured as a single vitreous china fixture. Typically, one-piece toilets have a lower profile than two-piece toilets.

Oriented Strand Board or OSB or Chip Board or Wafer Board: A manufactured wood panel made out of 1"- 2" wood chips and glue. Often used as a substitute for plywood in the exterior wall and roof sheathing.

Organic felt: An asphalt roofing base material manufactured from cellulose fibers.

Overhang: The portion of the roof structure that extends beyond the exterior walls of a building.

Over flow tube: The vertical tube inside a toilet tank (usually part of the flush valve), which directs water into the bowl in case the Ball cock malfunctions. If the Ball cock does not shut off properly, water will drain through the overflow tube into the bowl, and flow harmlessly over the dam and out the drain. This prevents potential water damage caused by the tank overflowing, and indicates to the user that there is a problem by a "constant running" condition.