# Multi-Family Residential Design

## Unit Types and Sizes

### Standard Unit Types
| Type | Bedrooms | Min SF | Typical SF |
|------|----------|--------|------------|
| Micro | 0 (studio) | 200-350 | 300-400 |
| Studio | 0 | 350-500 | 450-550 |
| Junior 1BR | 0+alcove | 450-550 | 500-600 |
| 1 Bedroom | 1 | 550-750 | 650-850 |
| 1BR + Den | 1+den | 700-900 | 800-1,000 |
| 2 Bedroom | 2 | 850-1,100 | 950-1,200 |
| 2BR + Den | 2+den | 1,000-1,300 | 1,100-1,400 |
| 3 Bedroom | 3 | 1,100-1,500 | 1,200-1,600 |
| Townhouse | 2-3 | 1,400-2,200 | 1,600-2,000 |

### Room Size Minimums
| Room | Min SF | Min Dimension |
|------|--------|---------------|
| Living room | 120 SF | 10'-0" |
| Dining area | 80 SF | 8'-0" |
| Kitchen | 50 SF | 5'-0" |
| Master bedroom | 120 SF | 10'-0" × 10'-0" |
| Secondary bedroom | 80 SF | 8'-0" × 8'-0" |
| Bathroom (full) | 40 SF | 5'-0" × 8'-0" |
| Bathroom (3/4) | 36 SF | 5'-0" × 6'-0" |

---

## Building Types

### Low-Rise (1-4 Stories)
| Type | Description |
|------|-------------|
| Garden | 2-3 story, no elevator |
| Walk-up | 3-4 story, no elevator |
| Stacked flat | Townhouse-style, 2 levels |
| Podium | 1-2 level parking, 3-4 residential |

### Mid-Rise (5-8 Stories)
| Feature | Typical |
|---------|---------|
| Construction | Wood over concrete, or all concrete |
| Elevator | Required (2+ recommended) |
| Corridor | Double-loaded typical |
| Parking | Structured or underground |

### High-Rise (9+ Stories)
| Feature | Typical |
|---------|---------|
| Construction | Concrete or steel frame |
| Elevators | 1 per 50-75 units |
| Corridor | Double-loaded or point tower |
| Parking | Underground or adjacent structure |
| Amenities | Extensive common areas |

---

## Corridor Design

### Double-Loaded Corridor
- Units on both sides
- Most efficient (70-75% efficiency)
- 5'-0" to 6'-0" width minimum
- Max dead-end: 20' (unsprinklered), 50' (sprinklered)

### Single-Loaded Corridor
- Units on one side only
- Less efficient (60-65%)
- Natural light to corridor
- Views to courtyard/exterior

### Point Tower/Skip-Stop
- Central core with 2-4 units per floor
- Very efficient for high-rise
- Premium units with corner exposure

### Efficiency Calculations
| Building Type | Net-to-Gross |
|---------------|--------------|
| Efficient layout | 78-82% |
| Average layout | 72-78% |
| Complex layout | 68-72% |
| Tower/amenity-rich | 62-68% |

---

## Parking Requirements

### Typical Ratios
| Unit Type | Ratio |
|-----------|-------|
| Studio | 0.75-1.0 |
| 1 Bedroom | 1.0-1.5 |
| 2 Bedroom | 1.5-2.0 |
| 3 Bedroom | 2.0-2.5 |
| Urban/transit | 0.5-1.0 reduced |

### Parking Types
| Type | SF/Space | Cost |
|------|----------|------|
| Surface | 300-350 SF | $ |
| Covered surface | 300-350 SF | $$ |
| Structured above | 320-380 SF | $$$ |
| Underground | 350-400 SF | $$$$ |

### ADA Requirements
| Total Spaces | Accessible |
|--------------|------------|
| 1-25 | 1 |
| 26-50 | 2 |
| 51-75 | 3 |
| 76-100 | 4 |
| 101-150 | 5 |
| 150+ | 2% + 1 |

---

## Amenity Spaces

### Common Area Types
| Amenity | Typical Size |
|---------|--------------|
| Lobby/leasing | 500-1,500 SF |
| Clubhouse | 1,500-3,500 SF |
| Fitness center | 750-2,500 SF |
| Pool deck | 2,000-5,000 SF |
| Business center | 200-500 SF |
| Package room | 100-300 SF |
| Dog park | 2,000-5,000 SF |
| Rooftop terrace | Varies |

### Per-Unit Allowances
| Amenity Level | SF/Unit |
|---------------|---------|
| Basic | 5-10 SF |
| Standard | 15-25 SF |
| Premium | 30-50 SF |
| Luxury | 50+ SF |

### Amenity Planning
| Project Size | Amenities |
|--------------|-----------|
| < 100 units | Lobby, fitness, laundry |
| 100-200 units | + Pool, clubhouse, business center |
| 200-350 units | + Dog park, rooftop, theater |
| 350+ units | + Spa, co-working, multiple pools |

---

## Unit Design Principles

### Layout Goals
- Entry foyer for transition
- Living areas toward views
- Bedrooms toward quiet side
- Kitchen near entry (short grocery carry)
- Minimize hallway space
- Natural light in all habitable rooms

### Bedroom Requirements
| Requirement | Code |
|-------------|------|
| Minimum area | 70-80 SF (varies by code) |
| Minimum dimension | 7'-0" |
| Ceiling height | 7'-0" minimum |
| Window | 8% of floor area |
| Closet | Required in most codes |
| Egress window | Required for sleeping rooms |

### Kitchen Minimums
| Feature | Requirement |
|---------|-------------|
| Counter | 18" on each side of sink |
| Clearance | 40" between counters (36" min) |
| Appliances | Range, refrigerator, sink |
| Ventilation | Exhaust required |
| Lighting | Task at sink/stove |

### Bathroom Requirements
| Feature | Full Bath | 3/4 Bath | Half Bath |
|---------|-----------|----------|-----------|
| Toilet | ✓ | ✓ | ✓ |
| Lavatory | ✓ | ✓ | ✓ |
| Tub/shower | ✓ | Shower only | - |
| Min size | 5'×8' | 5'×6' | 3'×5' |

---

## Accessibility

### Fair Housing Requirements
- Ground floor units OR elevator-served
- Accessible entrance/route
- Accessible common areas
- Adaptable unit features

### Adaptable Features
| Feature | Requirement |
|---------|-------------|
| Door widths | 32" clear minimum |
| Blocking | In walls for grab bars |
| Switches/outlets | 15"-48" AFF |
| Kitchen | Clear knee space under sink |
| Bathroom | 30"×48" clear floor space |

### Type A vs Type B Units
| Feature | Type A | Type B |
|---------|--------|--------|
| Full accessibility | ✓ | Adaptable |
| Turning radius | 60" | 60" |
| Door widths | 32" | 32" |
| Blocking installed | ✓ | ✓ |
| Grab bars installed | ✓ | Blocking only |
| Roll-in shower | Required | Tub OK |

---

## Fire/Life Safety

### Building Classification
| Type | Construction | Sprinklers |
|------|--------------|------------|
| R-2 | Various | Required > 2 stories |
| R-2 | Wood | Max 4 stories typically |
| R-2 | Protected wood | Up to 5-6 stories |
| R-2 | Concrete/steel | Unlimited |

### Separation Requirements
| Separation | Rating |
|------------|--------|
| Unit to unit | 1 hour |
| Unit to corridor | 20 min (sprinklered) |
| Unit to corridor | 1 hour (unsprinklered) |
| Floor to floor | 1 hour |
| Stair enclosure | 1 hour (< 4 stories) |
| Stair enclosure | 2 hour (> 4 stories) |

### Egress Requirements
| Feature | Requirement |
|---------|-------------|
| Exit access | 2 exits if > 10 occupants |
| Travel distance | 200' (sprinklered) |
| Dead end | 50' max (sprinklered) |
| Corridor width | 44" |
| Door width | 32" clear min |

---

## Acoustics

### STC/IIC Requirements
| Separation | STC | IIC |
|------------|-----|-----|
| Unit to unit | 50 | 50 |
| Unit to corridor | 50 | - |
| Unit to exterior | 45+ | - |
| Field tested (ASTC/AIIC) | 45 | 45 |

### Common Issues
| Source | Solution |
|--------|----------|
| Footfall noise | Resilient underlayment |
| Plumbing noise | Pipe isolation, planning |
| Mechanical noise | Equipment isolation |
| Corridor noise | Gaskets, solid doors |
| Neighbor TV/music | Enhanced wall assembly |

---

## MEP Systems

### Mechanical Options
| System | Use |
|--------|-----|
| PTAC | Affordable/garden style |
| Split system | Individual control |
| VRF | Mid-rise, efficiency |
| Central plant | High-rise |

### Electrical per Unit
| Feature | Typical |
|---------|---------|
| Service size | 100-200A |
| Panel location | Entry closet or utility |
| Metering | Individual, in corridor |

### Plumbing Layout
| Strategy | Benefit |
|----------|---------|
| Stacked wet walls | Reduce risers |
| Back-to-back bathrooms | Share plumbing wall |
| Kitchen near bath | Short waste runs |
| Laundry in bathroom | Combine drains |

---

## Unit Mix

### Typical Mix by Market
| Market | Studio | 1BR | 2BR | 3BR |
|--------|--------|-----|-----|-----|
| Urban | 20% | 50% | 25% | 5% |
| Suburban | 10% | 45% | 35% | 10% |
| Family | 5% | 30% | 45% | 20% |

### Market Considerations
| Factor | Impact |
|--------|--------|
| Demographics | Family vs. singles |
| Rent levels | Mix toward revenue |
| Competition | Differentiate |
| Location | Transit vs. suburban |

---

## Florida-Specific

### Hurricane Requirements
| Feature | Requirement |
|---------|-------------|
| Windows | Impact or shutters |
| Doors | Impact rated |
| Roof | Enhanced attachment |
| Garage doors | Impact rated |

### Flood Requirements
| Zone | Requirement |
|------|-------------|
| AE/VE | Elevated construction |
| X500 | Standard |
| Coastal A | Breakaway walls |

### Energy (Florida Code)
| Feature | Requirement |
|---------|-------------|
| Wall R-value | R-13 minimum |
| Ceiling R-value | R-30 minimum |
| Windows | U-0.65/SHGC-0.25 |
| HVAC | SEER 15+ |
