Room Addition Contractor in Westchester CA — Costs & Planning (2026)

Room Addition Contractor in Westchester, CA — Costs and Planning (2026)

Westchester’s West LA pricing and flat South Bay-adjacent topography make room additions a practical alternative to moving to a larger property. At $900K–$1.5M home values, adding 400–800 square feet is significantly more economical than purchasing a larger home in the same market — and keeps homeowners in the neighborhood they’ve invested in. Westchester’s post-war grid streets feature flat lots well-suited for single-story additions. APLA Construction (CA Lic #1136359) handles Westchester room additions from design through LADBS permit to final inspection.

Room Addition Costs in Westchester (2026)

• Bedroom addition (200–300 sq ft): $75,000–$128,000
• Master suite addition (400–600 sq ft): $105,000–$192,000
• Family room expansion (400–600 sq ft): $95,000–$172,000
• Home office addition (200–300 sq ft): $70,000–$115,000

Westchester room addition pricing is at West LA rates — appropriate for the neighborhood’s $900K–$1.5M home values, similar to Mar Vista, below Santa Monica and Culver City premium.

Westchester Room Addition Process

Design and Permit ($4,500–$10,000)

Architectural plans, structural engineering, and LADBS plan check submission. LADBS standard plan check for room additions: 6–10 weeks.

Foundation and Framing ($20,000–$48,000)

New foundation matching existing home construction type. Standard slab or raised wood floor on flat Westchester lots.

MEP, Insulation, and Finishes ($22,000–$52,000)

Electrical, HVAC extension, plumbing (if suite addition), insulation (Title 24), drywall, flooring, and trim.

Frequently Asked Questions — Room Addition Westchester

How much does a room addition cost in Westchester in 2026?

Master suite: $105,000–$192,000. Family room: $95,000–$172,000. Bedroom: $75,000–$128,000. Westchester is at West LA mid-market pricing — appropriate for homes valued $900K–$1.5M.

Does APLA build room additions in Westchester?

Yes. APLA (CA Lic #1136359) serves Westchester, Playa Vista, Mar Vista, and the West LA corridor. Call (818) 818-4419 for a free estimate.

Start Your Westchester Room Addition

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

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