Calculateur de Retrait et Surface Constructible — Formule

## Setback & Buildable Area

Setbacks are the minimum required distances between a building and the property lines. They create the "buildable envelope" that constrains where a structure can be placed on a lot.

### Setback Types

- **Front setback**: Distance from the front property line (street-facing), typically 15-30 ft
- **Rear setback**: Distance from the rear property line, typically 15-25 ft
- **Side setback**: Distance from each side property line, typically 5-15 ft
- **Corner lots**: May have two front setbacks

### Calculating the Buildable Envelope

**Buildable Width = Lot Width - (Side Setback x 2)**
**Buildable Depth = Lot Depth - Front Setback - Rear Setback**
**Buildable Area = Buildable Width x Buildable Depth**

### Additional Constraints

Setbacks define the maximum footprint, but the actual building may be smaller due to:
- Lot coverage limits
- Floor area ratio (FAR) limits
- Parking requirements
- Building height restrictions