Adding square footage to your Westchester home is often more cost-effective than moving – especially in today’s Los Angeles real estate market. This guide covers realistic 2026 room addition costs, what drives pricing, and what Westchester homeowners can expect from the permit and construction process. APLA Construction Group Inc. (CA Lic #1136359) serves Westchester with licensed room addition construction and free on-site estimates.
| Item | Typical Cost |
| Standard bedroom addition (400 sq ft) | $92,000-$162,000 – Includes foundation extension, framing, roofing, insulation, drywall, flooring, electrical, and paint. Does not include a bathroom. |
| Primary suite addition (600 sq ft with bath) | $152,000-$268,000 – Bedroom, walk-in closet, and full ensuite bathroom. Includes all plumbing rough-in and finish work. |
| Second story addition | $250,000-$460,000 – Full second floor addition. Requires structural engineering, temporary relocation of roof, staircase, and full mechanical integration. |
| Sunroom or bonus room (300 sq ft) | $60,000-$110,000 – Lighter construction, may use patio foundation, typically no plumbing. |
Westchester is a stable neighborhood near LAX where family buyers consistently look for additional bedroom capacity. Room additions here serve a clear market need and tend to be reflected in proportionally higher sale prices.
Key factors affecting your room addition cost in Westchester:
Room additions in Westchester typically cost $200-$420 per square foot all-in (design, permits, construction, finishes). The lower end applies to simple single-story additions with standard finishes; the upper end reflects additions with complex roof integration, bathroom plumbing, or premium finish specifications.
All room additions in Westchester require permits covering structural, electrical, plumbing, and mechanical work. The permit process typically takes 4-8 weeks for approval. APLA Construction manages the entire permit process – including plan preparation coordination, city submission, and all required inspections. We never begin structural work without proper permits in place.
A standard 400 sq ft bedroom addition in Westchester costs $92,000-$162,000. A primary suite with bathroom runs $152,000-$268,000. A second story addition costs $250,000-$460,000. Costs vary based on foundation conditions, roof complexity, plumbing scope, and finish level. APLA Construction provides free detailed estimates – call (818) 818-4419.
From first consultation to final inspection, most room additions in Westchester take 5-8 months. Permitting alone takes 4-8 weeks. Construction takes 10-18 weeks depending on the scope. APLA Construction provides a written project schedule before work begins.
Yes – all room additions require engineer-stamped structural drawings as part of the permit package. APLA Construction coordinates with licensed structural engineers as part of the permit preparation process. This is included in our project management scope.
Room additions in the Los Angeles market typically return 50-70% of project cost at resale in direct value, with additional benefits from faster sale times and higher buyer demand. Primary suite additions and additions that bring a home from 2-bedroom to 3-bedroom often return more than this benchmark given the significant jump in market comparables.
Yes. APLA Construction Group Inc. (CA Lic #1136359) serves Westchester and all of Playa del Rey, El Segundo, Hawthorne, Inglewood, and the LAX corridor. We handle all phases of room addition projects – design coordination, permits, foundation, framing, MEP, and finish work. Call (818) 818-4419 or email info@aplaconstruction.com for a free consultation.
APLA Construction Group Inc. is a licensed general contractor (CA Lic #1136359) serving Westchester and greater Los Angeles. Free estimates, transparent pricing, written schedules – no surprises.
Call: (818) 818-4419
Email: info@aplaconstruction.com
CA Lic #1136359 — verify on CSLB
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