Create an early material takeoff for a simple rectangular home addition. From floor area, perimeter, wall height, openings, and waste allowance, the calculator estimates slab concrete, exterior studs, wall drywall, roof area, and insulation. It is intended for feasibility planning before drawings and supplier takeoffs are available.
The quantities are conceptual takeoff values for a simple shell. They help size orders and compare schemes, but structural plans determine actual framing, foundation, headers, roof assemblies, and code-required materials.
Do not order structural materials from this estimate alone. A designer, engineer, contractor, or supplier should prepare a drawing-based takeoff.
A 400 sq ft addition with a 4-inch slab and 10% waste needs:
The displayed wall and roof quantities use the entered 80 ft perimeter, 9 ft height, 15% openings, and 1.15 roof factor.
No. It estimates only a uniform slab at the entered thickness.
Different shapes can have the same area but very different wall lengths and material needs.
No. The estimate uses exterior wall area only; add partition wall faces separately.
The entered opening percentage reduces wall sheathing, drywall, and insulation area.
Yes. Use a factor above 1.00 to account for slope and overhang, based on the planned geometry.
| Output | Planning unit |
|---|---|
| Slab concrete | Cubic yards |
| Exterior studs | Individual studs |
| Drywall | 4 × 8 ft sheets |
| Roof surface | Square feet |
| Insulation | Square feet |