Room Addition Cost Los Angeles 2026 | Complete Pricing Guide

Quick answer: A room addition costs $80,000–$450,000 in Los Angeles, depending on whether it’s a single-story addition or a second-story build. APLA Construction (CA Lic #1136359) provides free estimates across Greater Los Angeles.

Room Addition Cost in Los Angeles — Complete 2026 Pricing Guide

What does a room addition cost in Los Angeles? It is one of the most common questions homeowners ask before deciding whether to build or buy. In 2026, room addition costs in Greater LA range from $80,000 for a basic bedroom addition to $450,000+ for a full second story addition. This guide breaks down every cost category so you can plan your budget accurately. APLA Construction (CA Lic #1136359) has managed room addition projects throughout Los Angeles and these figures reflect current construction costs in the market.

Estimate Your Project Cost

A starting-point range based on real Los Angeles pricing — not a substitute for a free on-site estimate.

Project type Finish level

Estimates reflect typical Greater Los Angeles pricing as of 2026 and can vary based on site conditions, permitting jurisdiction, and design decisions. CA Lic #1136359.

Addition Type	Typical Cost Range
Bedroom addition	$80,000–$165,000
Primary suite addition	$125,000–$240,000
Family room / great room addition	$110,000–$210,000
Second story addition	$220,000–$450,000+

Room Addition Costs by Type — Los Angeles 2026

Bedroom Addition Cost — $80,000 to $165,000

A single bedroom addition (200–400 sq ft) is the most straightforward addition type. It adds a room to an existing level of the house, typically with a closet, and may or may not include a bathroom.

Foundation extension: $6,000–$14,000
Framing and roofing: $14,000–$26,000
Electrical (circuits, outlets, lighting): $4,000–$8,000
HVAC extension: $3,000–$6,000
Insulation, drywall, flooring, interior finishes: $18,000–$32,000
Windows and doors: $4,000–$9,000
Permits, design, engineering: $8,000–$18,000
Total bedroom addition: $80,000–$165,000

Primary Suite Addition Cost — $125,000 to $240,000

A primary suite addition includes a bedroom plus a dedicated bathroom. This is the most popular addition type in Los Angeles, as many older homes lack a proper primary suite.

Foundation: $8,000–$18,000
Framing, roofing, exterior: $20,000–$38,000
Electrical: $6,000–$12,000
Plumbing (full bathroom rough-in): $8,000–$16,000
HVAC: $4,000–$8,000
Insulation, drywall: $14,000–$22,000
Bathroom tile, vanity, fixtures: $22,000–$42,000
Flooring, trim, interior finishes: $12,000–$22,000
Closet build-out: $5,000–$12,000
Permits, design, engineering: $12,000–$22,000
Total primary suite addition: $125,000–$240,000

Family Room / Great Room Addition Cost — $110,000 to $210,000

A family room or great room addition (400–600 sq ft) typically opens to the existing kitchen or living area. Often involves removing a wall and adding a beam to connect the addition to the existing space.

Foundation: $8,000–$18,000
Framing and roofing: $18,000–$35,000
Beam installation (structural): $5,000–$12,000
Electrical and lighting: $8,000–$14,000
HVAC: $4,000–$8,000
Insulation, drywall, flooring: $20,000–$35,000
Windows, sliding door, exterior finishes: $12,000–$22,000
Permits, design, engineering: $10,000–$18,000
Total family room addition: $110,000–$210,000

Second Story Addition Cost — $220,000 to $450,000+

A full second story addition (full floor, typically 1,000–1,800 sq ft) transforms a single-story home into a two-story home. It is the most complex type of addition and often involves significant structural reinforcement of the existing first floor, plus a staircase, new roof, and complete MEP for the upper floor.

Structural engineering and design: $18,000–$35,000
Temporary shoring and first-floor structural reinforcement: $12,000–$25,000
Framing: $28,000–$52,000
Roofing: $14,000–$26,000
MEP rough-in (full floor): $30,000–$55,000
Insulation, drywall, interior finishes: $35,000–$65,000
Staircase: $8,000–$18,000
Windows and exterior: $18,000–$35,000
Permits and plan check: $15,000–$28,000
Total second story addition: $220,000–$450,000+

See our detailed second story addition guide for Los Angeles.

What Affects Room Addition Costs in Los Angeles?

Jurisdiction: City of LA (LADBS) vs. municipalities with their own building departments (Santa Monica, Culver City, Pasadena, Glendale, Burbank) — independent cities may have different permit fees and requirements
Lot conditions: Hillside lots, poor soil conditions, or high fire hazard zones add cost
Existing structure condition: Older homes may require electrical panel upgrades, foundation reinforcement, or other work to support an addition
Finish level: Standard finishes vs. premium tile, custom cabinetry, hardwood flooring — the difference between a $130K and $200K primary suite
Design complexity: Simple rectangular additions cost less than additions with complex rooflines, multiple window arrangements, or custom exterior detailing

Room Addition vs ADU in Los Angeles

The most common decision Los Angeles homeowners face: build an addition to expand living space, or build an ADU that generates rental income. The financial calculation is clearer than most people think:

A room addition adds space but no income — it adds value through improved livability and square footage
An ADU generates $1,800–$3,500/month in rental income AND adds $200,000–$400,000 in property value
If you need the space for personal use, a room addition is the right choice. If the goal is income or property value maximization, an ADU usually wins

See our full comparison: ADU vs Room Addition Los Angeles.

Frequently Asked Questions — Room Addition Cost Los Angeles

How much does a bedroom addition cost in Los Angeles in 2026?

A bedroom addition (200–400 sq ft) in Los Angeles costs $80,000–$165,000 in 2026, including foundation, framing, MEP rough-in, interior finishes, and permits. Adding a bathroom to the bedroom pushes the cost to a primary suite range of $125,000–$240,000.

How much does a second story addition cost in Los Angeles?

A full second story addition in Los Angeles costs $220,000–$450,000+. The wide range reflects variation in size (1,000–1,800 sq ft), structural complexity (some first floors require significant reinforcement), finish level, and permit jurisdiction. Second story additions in cities with their own building departments (Santa Monica, Pasadena) may have higher permit costs.

How long does a room addition take in Los Angeles?

A bedroom or primary suite addition in Los Angeles takes 10–16 months total: 4–6 weeks for design and engineering, 5–10 weeks for permit processing (LADBS or applicable city), and 14–24 weeks for construction. A second story addition takes 14–22 months total due to the larger construction scope.

Do I need permits for a room addition in Los Angeles?

Yes. All room additions in Los Angeles require building permits. Structural work requires stamped engineering calculations. Additions in hillside zones, coastal zones, or historic districts may require additional review. APLA handles all permit coordination for room addition projects throughout Greater Los Angeles.

Get a Free Room Addition Estimate

APLA provides free on-site consultations and written estimates for room additions throughout Greater Los Angeles.

Call: (818) 818-4419
Email: info@aplaconstruction.com
CA General Contractor License #1136359 — verify on CSLB

Serving Sherman Oaks, Studio City, Encino, Culver City, Santa Monica, Pasadena, Glendale, and all of Greater Los Angeles. Learn more about our room addition services.

More Room Addition Guides

Get a Free Quote →

Room Addition Cost Los Angeles — Complete 2026 Pricing Guide