Project Inputs
Example Data Table
| Area (sq ft) | Thickness (in) | Exposure | Temp | RH (%) | Vent (ACH) | Fans (CFM) | Dehum (pints/day) | Estimated Time (hours) |
|---|---|---|---|---|---|---|---|---|
| 200 | 0.5 | Light | 24°C | 45 | 3 | 800 | 30 | ~28 |
| 350 | 0.625 | Moderate | 20°C | 60 | 2 | 1200 | 40 | ~61 |
| 500 | 0.5 | Heavy | 18°C | 75 | 1 | 1500 | 50 | ~96 |
Examples are planning estimates. Always verify moisture levels before closing assemblies.
Formula Used
Core estimate
Estimated Hours = BaseHours × ThicknessFactor × SaturationFactor × TempFactor × HumidityFactor × VentFactor × DehumidifierFactor
- BaseHours: 48 hours baseline at 21°C, 50% RH, about 3 ACH.
- ThicknessFactor: thickness_in ÷ 0.5.
- SaturationFactor: Light 1.00, Moderate 1.40, Heavy 1.85.
- TempFactor: (21 ÷ max(tempC, 5))^0.60, bounded 0.60–2.50.
- HumidityFactor: (RH ÷ 50)^0.90, bounded 0.70–2.20.
- VentFactor: 3 ÷ EffectiveACH, bounded 0.35–2.00.
- EffectiveACH: vent_ach + (fans_cfm × 60) ÷ (area_sqft × 8).
- DehumidifierFactor: 1 ÷ (1 + (pints/day ÷ 60) × (500 ÷ area)), bounded 0.40–1.00.
How to Use This Calculator
- Enter the approximate affected drywall area in square feet.
- Set drywall thickness and choose the water exposure level.
- Enter room temperature and relative humidity percentage.
- Add ventilation ACH, total fan airflow, and dehumidifier capacity.
- Press Calculate to see the estimate above the form.
- Use the download buttons to save CSV or PDF output.
- Confirm dryness with a meter before repairs and paint.
Practical Notes
- Remove wet insulation and trapped water sources early.
- Keep airflow moving across surfaces, not into walls.
- Lower humidity first, then maintain steady warmth.
- If discoloration or odor appears, inspect for hidden moisture.