It depends on the element and conditions. For walls and columns, forms can typically be stripped after 24–48 hours at 70°F when using Type I cement — concrete reaches roughly 70% of 28-day strength by day 7. For slabs carrying loads, ACI 347 recommends waiting until at least 75% strength is achieved, which is typically 7 days at normal temperatures. Cold weather slows strength gain significantly — below 50°F, add 50–100% more time. Use the curing time calculator to get precise milestones for your conditions.

For a rectangular cut, multiply length × width × depth to get bank cubic yards. To find the loose volume for trucking, multiply bank volume by the swell factor for your soil type — typically 1.25 for clay, 1.12 for sandy loam, and 1.30 for rock. Divide loose volume by your truck capacity (usually 10–14 cy) to get truck loads. The excavation calculator handles all of this automatically and outputs both bank and loose volumes with truck count.

ACI 308 recommends a minimum of 7 days of moist curing for Type I/II Portland cement concrete at temperatures above 50°F. Concrete reaches approximately 70% of 28-day strength at 7 days, 85% at 14 days, and 99% at 28 days. For Type III (high-early strength) cement, 3 days achieves similar results to 7 days with Type I. Cold weather below 40°F essentially stops hydration — concrete must be protected and kept above 50°F throughout the curing period.

For a standard wall form using 3/4-inch plywood, you need one sheet (4×8 ft = 32 sq ft) per 32 sq ft of form face area. Studs are typically spaced 12–16 inches on center, with wales every 2 feet for walls over 4 feet tall. For a 10 ft × 20 ft wall (both faces = 400 sq ft of form), you’d need approximately 13 sheets of plywood per face, plus framing lumber and ties. The formwork calculator handles the full material takeoff including studs, wales, and hardware.

Pump output depends on five main factors: line diameter (4-inch lines deliver roughly 60–80 cy/hr vs 30–40 cy/hr for 3-inch), line length and elevation (friction and head pressure reduce output), concrete slump (higher slump pumps faster — minimum 4 inches recommended), aggregate size (maximum 1/3 of line diameter), and pump type (trailer pump vs boom pump). A standard trailer pump on a residential pour averages 30–50 cy/hr under normal conditions. The pump output calculator (coming soon) will model all five variables.