Data Sources

• Normal-weight concrete fresh density typically ~ 140–150 lb/ft³ (2240–2400 kg/m³).
• Common 60-lb concrete bag yield ≈ 0.45 ft³ (varies by brand and slump).

Variance drivers: mix design, air content, moisture, placement method.

• Most 3-tab and many architectural shingles: ~3 bundles per square (varies by brand).
• Starter/hip & ridge have different coverage — accounted for in waste.

Variance drivers: shingle style/brand, exposure, roof complexity, pitch.

• Attic insulation: R-30 to R-60 depending on climate zone.
• Wall insulation: typically R-13 to R-21 depending on stud size and zone.

Variance drivers: climate zone, local energy code adoption, existing insulation condition.

• Compacted HMA density often assumed near ~145 lb/ft³ (2320 kg/m³) for planning.
• Common drive/path lifts: 1.5–3.0 in compacted thickness (project-specific).

Variance drivers: mix design, aggregate, temperature, roller pattern, local specs.

• Loose aggregate unit weight commonly ranges ~95–120 lb/ft³ (1520–1920 kg/m³).
• Moisture and gradation materially affect bulk density and coverage.

Variance drivers: particle shape, fines content, moisture, compaction energy.

• Common yields (approx.): 40-lb ≈ 0.30 ft³, 50-lb ≈ 0.375 ft³, 60-lb ≈ 0.45 ft³, 80-lb ≈ 0.60 ft³.
• Yields vary with water content and placement; always verify on the bag/TDS.

Variance drivers: slump, entrained air, compaction, brand formulation.

• Typical coverage on smooth walls: ~350–400 ft²/gal per coat.
• Rough/porous substrates, deep tints, and low-temp application reduce coverage.

Variance drivers: substrate, primer use, roller/airless method, VOC limits, sheen.

• Waste allowances often start around 10–15%, higher for hips/valleys.

Variance drivers: roof geometry, starter/ridge details, patterning, local practice.

• Standard sheet size: 4×8 ft; waste allowance typically 10% for straightforward layouts.

Variance drivers: panel grade, span rating, application (sheathing, subfloor, underlayment).

• Waste allowances typically 10% for straight-lay rooms, higher for diagonal layouts or complex room shapes.

Variance drivers: plank size, layout pattern, room shape, transitions.

• Standard single rolls cover roughly 28–36 sq ft of usable wall after trim and pattern matching.

Variance drivers: pattern repeat size, wall height, number of openings, installer waste.

• Floor coating coverage varies widely by product and substrate porosity — always confirm against the specific product's TDS.

Variance drivers: substrate porosity, coat thickness, mix ratio, product formulation.

• Common residential slab thicknesses: 4–6 in (project-specific; follow local code).

Variance drivers: loads, climate, soil, reinforcement, local code and engineering.

Reinforces formulas for area, volume, roof pitch geometry, board feet, and rounding to purchase units.

• Standard stud spacing: 16 in or 24 in on-center, depending on wall height and load.
• Joist/rafter spans vary by species, grade, spacing, and load — always confirmed against published span tables, not a fixed rule of thumb.

Variance drivers: lumber species and grade, live/dead load assumptions, deflection limits.

• Waste allowances typically start around 10%, higher for diagonal layouts or intricate patterns.

Variance drivers: tile size, layout pattern, room shape, grout joint width.

• Standard sheet sizes: 4×8 ft and 4×12 ft; waste allowance typically 10–15%.

Variance drivers: room geometry, ceiling height, opening count, framing type.

• Sizing depends on household size, water hardness (grains per gallon), and daily usage.

Variance drivers: water hardness, household size, iron content, peak usage patterns.