QuantityBench Construction Material Glossary
Plain-language definitions for terms used across this site's calculators — grouped by topic, each linking to the calculator or guide where it's actually used.
Volume and weight
- Aggregate — a general term for loose material like gravel, crushed stone, or sand used as a base layer or fill. Used throughout the Gravel Calculator.
- Cubic yard — 27 cubic feet (3×3×3 ft), the standard unit suppliers use to price and deliver bulk gravel, sand, and ready-mix concrete.
- Density (tons per cubic yard) — how much a cubic yard of a specific material weighs. Standard gravel is about 1.4 tons per cubic yard; crushed stone, being denser, is about 1.5. See Gravel vs. Crushed Stone for why.
- Waste allowance — extra material (typically 10%) added on top of the raw calculated volume to cover compaction, spillage, and an uneven sub-grade, so you don't come up short mid-project.
- Sub-base — the compacted layer (often gravel or crushed stone) beneath a concrete slab, asphalt surface, or paver patio that provides drainage and load support.
Concrete
- Ready-mix concrete — concrete mixed at a plant and delivered by truck, typically ordered by the cubic yard. Usually more economical than bags once a pour needs roughly a cubic yard or more.
- Premix (bagged) concrete — dry concrete mix in 40, 60, or 80 lb bags that you add water to on site. Practical for small pours like fence post footings; the Concrete Calculator converts a slab volume into bag counts for all three sizes.
- Slab thickness — how deep the poured concrete is, measured in inches. A patio or walkway is typically thinner than a driveway slab meant to bear vehicle weight.
Asphalt
- Hot-mix asphalt — asphalt mixed and applied hot, the standard material for driveways and paving. Its estimating density (used by the Asphalt Calculator) is around 145 lb per cubic foot, though exact mixes vary.
- Sealcoating — a protective coating applied to cured asphalt every few years to slow water penetration and UV damage — the main routine maintenance asphalt needs. See Asphalt vs. Concrete Driveway.
Fencing
- Post spacing — the distance between fence posts along the fence line; fewer, more widely spaced posts means less digging and concrete but more strain per post. See Fence Post Spacing.
- Picket pitch — the width of one picket plus the gap next to it; used by the Fence Calculator to work out how many pickets fit a section.
- Rail — the horizontal board or bar connecting posts that pickets are attached to; most residential fences use two or three rail rows per section.
Roof pitch
- Rise and run — in US residential roofing, pitch is expressed as inches of rise per 12 inches of run (the "x/12" system): a 4/12 roof rises 4 inches for every 12 inches measured horizontally.
- Slope factor — a multiplier that converts a flat (plan-view) roof area into the actual sloped surface area, since a pitched roof has more surface than its footprint suggests.
- Rafter length — the length of the sloped structural member running from the roof's ridge to its eave, longer than the horizontal run because of the pitch. Calculated by the Roof Pitch Calculator.
Frequently asked questions
What's the difference between a cubic foot and a cubic yard?
A cubic yard is 27 cubic feet (3 ft x 3 ft x 3 ft). Suppliers usually quote and deliver gravel, sand, and ready-mix concrete by the cubic yard because a cubic foot is too small a unit for bulk material — but calculators often work in cubic feet internally before converting, which is why you may see both numbers on a result.
Why do these definitions matter if the calculator does the math for me?
Knowing the terms helps you talk to a supplier or contractor and catch a mismatch — for example, ordering "gravel" when a quote is actually for "crushed stone" changes the weight per cubic yard. See the Methodology page for exactly which reference numbers this site uses for each term.
Where do these definitions come from?
They reflect common US residential construction and landscaping-supply usage, matching the terminology used on each calculator page on this site. Regional or trade-specific usage can vary slightly — when in doubt, confirm with your local supplier what they mean by a given term.