Short answer. A typical Los Angeles master suite addition is 350 to 500 sq ft (bedroom, walk-in closet, primary bath) at $600 to $1,080 per sq ft, totaling $215,000 to $540,000. Most projects take 5 to 9 months from contract to completion.
Cost by size and quality
| Size | Mid-range total | High-end total |
|---|---|---|
| 350 sq ft | $215,000 to $300,000 | $300,000 to $420,000 |
| 500 sq ft | $300,000 to $420,000 | $420,000 to $600,000 |
| 700 sq ft | $420,000 to $575,000 | $575,000 to $780,000 |
What's included in cost
- Architectural design and engineering.
- Permits and plan check.
- Foundation, framing, roof.
- Electrical, plumbing, HVAC.
- Insulation, drywall, paint.
- Flooring (hardwood, tile, or LVP).
- Windows and exterior doors.
- Primary bathroom (vanity, toilet, shower, tub).
- Walk-in closet built-in storage.
- Connection to existing house (drywall patch, flooring continuation, paint).
Standard layout options
Single-story rear addition (most common)
- Extends off existing bedroom or living area.
- Direct yard access.
- Simplest construction.
- No structural reinforcement of existing house.
Second story over existing footprint
- No yard area lost.
- Requires foundation and structural reinforcement.
- 30 to 50 percent more expensive per sq ft than rear addition.
- Better view potential.
Garage conversion plus addition
- Reuses existing slab and walls for part of the suite.
- Lower cost per sq ft.
- Eliminates garage parking (verify city requirements).
Key layout decisions
- Closet vs bathroom side: closet between bedroom and bath buffers noise.
- Tub vs no tub: 70 percent of LA buyers expect a soaking tub in primary bath.
- Walk-in shower size: 4x5 minimum for comfort, 5x6 preferred.
- Dual sinks: standard expectation.
- Water closet (separate toilet room): preferred but adds 20 to 30 sq ft.
- Direct yard access: adds value, costs little.
- Fireplace or sitting area: niche feature, evaluate carefully.
For broader addition planning, see home addition cost. For second story options, read second story addition cost. For room additions, see our room additions page.
