Standard door, window & garage-door area deductions
Typical published planning values — NOT a certified spec or professional advice. Coverage and exposure vary by product and installation; confirm on the manufacturer’s installation instructions and stated coverage. Moisture, flashing, sheathing and pre-1978 lead paint on old siding are a pro’s call — follow the manufacturer’s instructions, local code and the EPA RRP rule and hire a certified firm; lead-paint abatement, structural and moisture repairs and code certification are not engineered here.
Net siding area is the gross wall + gable area minus the openings. These are the LABELED standard deductions — a door about 21 sq ft (3 × 7), a window about 15 sq ft, a patio door about 40, a single garage door about 63 (9 × 7) and a double garage door about 112 (16 × 7) — a planning convention you should adjust to your actual openings. Use them with the square-footage calculator and the how-much-siding calculator.
| Opening | Deduct (sq ft) |
|---|---|
| Standard door (3 × 7) | 21 |
| Standard window | 15 |
| Patio / sliding-glass door | 40 |
| Single garage door (9 × 7) | 63 |
| Double garage door (16 × 7) | 112 |
LABELED planning typicals — measure your actual openings. Deduct doors, windows and garage doors from the gross wall + gable area to get the net siding area; trimmed openings and small windows vary.