Construction Glossary
Plain-English definitions for every term you'll encounter when estimating materials.
B
- Board Footlumber
- A unit of lumber volume equal to 144 cubic inches — a board 1 inch thick, 12 inches wide, and 12 inches long.
C
- Cubic Yardconcrete
- A unit of volume equal to 27 cubic feet — the standard unit for ordering concrete, gravel, mulch, and topsoil in the United States.
- Concrete Bag Yieldconcrete
- The volume of finished concrete a single bag of mix produces — about 0.60 cubic feet for an 80-lb bag, 0.45 for a 60-lb, and 0.30 for a 40-lb.
- Coverage Rategeneral
- How much area one unit of a material covers — square feet per gallon of paint, per bag of mulch, or per ton of gravel at a given depth.
- Compacted Depthgravel
- The thickness of a material after compaction, which is less than the loose depth it was spread at — typically by 15% to 25% for crushed aggregate.
J
- Joist Spanframing
- The clear distance a joist can cross between supports without exceeding allowable deflection — governed by species, grade, size, spacing, and load.
L
- Linear Footlumber
- A measurement of length only — one foot along a piece of material, regardless of its width or thickness.
O
- On Center (OC)framing
- The spacing between framing members measured from the centre of one to the centre of the next, rather than the gap between them.
R
- Roofing Squareroofing
- A unit of roof area equal to 100 square feet — the unit shingles are sold and quoted in.
- Roof Pitchroofing
- The slope of a roof expressed as inches of vertical rise per 12 inches of horizontal run — a 6/12 roof rises 6 inches every foot.
- R-Valueinsulation
- A measure of thermal resistance — how well a material resists heat flow. Higher is better, and the values of layers in an assembly add together.
W
- Waste Factorgeneral
- The percentage added to a material estimate to cover cuts, breakage, and spillage — typically 5% to 15% depending on the material and layout.