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Home Addition Contractor in Woodland Hills, CA

Last updated: August 2026.

HomeSense Construction & Remodeling is a licensed general contractor building room additions, second-story additions and primary-suite expansions for Woodland Hills homeowners across 91364 and 91367. We are headquartered at 6571 Ponce Ave in neighboring West Hills — about 5–10 minutes from most of Woodland Hills — and have held California contractor license #1125001 since January 2011. A home addition is new conditioned floor area added to an existing house, and in Woodland Hills every addition we design is engineered to fit your lot’s zoning envelope — including the hillside and fire-zone rules that shape the south side of town — and to pass LADBS plan check on the first submittal.

Home Addition Services We Build in Woodland Hills

Woodland Hills splits into two very different building markets: flatter R1 tracts north of Ventura Boulevard, and larger hillside estate lots climbing into the Santa Monica Mountains to the south. We build in both:

  • Room additions & bump-outs — new bedrooms, great rooms, home offices, sunrooms and kitchen or dining expansions tied into your existing floor plan.
  • Second-story additions — full second floors and partial “pop-up” additions when a lot is maxed out horizontally or you want to capture Valley and mountain views.
  • Primary-suite additions — bedroom + spa bath + walk-in, the most requested add-on in Woodland Hills’ move-up market.
  • Hillside & view additions — cantilevers, caisson/grade-beam foundations and view decks on the sloped RE and RA lots south of the Boulevard.
  • Attached vs. detached expansions — including when an addition beats a detached ADU in Woodland Hills (covered below).

What Does a Home Addition Cost in Woodland Hills in 2026?

As of 2026, Woodland Hills single-story room additions typically run about $275–$605 per square foot — running roughly 110% of the Los Angeles County average because of the area’s higher-end finishes and hillside site work. Building up costs more: second-story additions generally run $400–$700 per square foot, because they require reinforcing the existing foundation and framing plus a roof-off construction phase. A realistic 2026 range by project size:

Addition Woodland Hills 2026 cost
300 sq ft room addition $105,000 – $200,000
400 sq ft room addition $140,000 – $260,000
500 sq ft primary suite $175,000 – $325,000
600 sq ft primary suite $250,000 – $400,000
Single-story, per square foot $275 – $605 / sq ft
Second-story addition, per square foot ~$400 – $700 / sq ft

For a line-by-line breakdown, see our room addition cost guide, our second-story addition cost guide and the full Los Angeles remodeling cost guides. We give a fixed written estimate after a site visit — no vague per-foot guesses.

How Long Does a Home Addition Take in Woodland Hills?

Plan on 4–7 months for design and permitting and 5–9 months of construction, so most Woodland Hills additions run about 9–16 months end to end. Hillside lots south of Ventura Boulevard sit longer in plan check because they trigger grading review and, in the fire zones, a Fire Department materials review. We give you a written schedule up front and manage the LADBS submittal so the permit phase does not drift.

Woodland Hills Zoning, Hillside & the 2026 Rules That Shape Your Addition

The real question is not “can I add on?” — it is “how much can this specific lot legally hold?” Woodland Hills answers differently depending on which side of the Boulevard you are on:

  • Flat R1 lots (north of Ventura Blvd): governed by the City of Los Angeles Baseline Mansionization Ordinance (LAMC 12.21.1). The base Residential Floor Area ratio is 0.45 of the lot size, with a 20% design/green bonus that can reach 0.50. On an 8,000 sq ft lot that caps total house area near 3,600–4,000 sq ft — we confirm your remaining buildable area before drawing anything.
  • Hillside RE/RA lots (south of Ventura Blvd): the Baseline Hillside Ordinance applies instead, and your buildable floor area is tied to lot slope — steeper lots get less. Grading limits, retaining-wall rules, sprinkler requirements and a stricter height/encroachment envelope all come into play.
  • Very High Fire Hazard Severity Zone (VHFHSZ): much of hillside Woodland Hills sits in a state-designated VHFHSZ inside the Wildland-Urban Interface. Additions there must meet California Building Code Chapter 7A — ignition-resistant siding and eaves, ember-resistant vents, dual-pane tempered glazing and Class-A roofing — plus defensible-space clearance. This is exactly the fire-hardened detailing we already build into our Woodland Hills roofing and new-construction work.

Permits & Code for Additions in Woodland Hills (LADBS)

Additions in Woodland Hills are permitted through the Los Angeles Department of Building and Safety. Because an addition creates new conditioned floor area, it always goes through full plan check — building, structural, electrical, plumbing and mechanical. Key 2026 requirements we design to:

  • Structural engineering: second-story and hillside additions require stamped structural plans confirming the existing foundation and framing can carry the new load; sloped or expansive-soil lots also need a soils/geotechnical report.
  • Title 24 (2026 Energy Code, effective 1/1/2026): new conditioned space must meet current standards for Climate Zone 9 — high-performance windows (about U-factor 0.27 / SHGC 0.23), a heat-pump baseline for space and water heating, and HERS field verification of ducts and envelope.
  • The ~50% rule: when an addition is combined with extensive remodeling that reaches the roughly 50% thresholds in the California Existing Building Code (and LAMC 12.03’s “Major Remodel” definition), broader upgrades — seismic, energy, egress — can be triggered for the whole house. We flag this early so it never becomes a mid-project surprise.

Room Addition vs. Second Story vs. ADU in Woodland Hills

Before you commit, the honest first question is whether an addition or a detached ADU serves you better. A room addition is best when you want the new space connected to your living area (a bigger kitchen, an extra bedroom). Building up makes sense when a flat lot is out of horizontal room, or a hillside lot has the views to justify it. A detached ADU is better when you want rental income or a private guest/in-law unit — and California’s 2026 rules are unusually owner-friendly: SB 1211 allows up to eight detached ADUs on qualifying multifamily lots, and AB 2533 lets owners legalize unpermitted ADUs and garage conversions built before January 1, 2020. We walk you through the trade-offs; see our ADU builder in Woodland Hills page and our room addition vs. ADU comparison.

Our Home Addition Process

Every Woodland Hills addition follows the same disciplined path: (1) site visit & feasibility — we measure the lot, confirm your zoning envelope, remaining floor area and any hillside/fire overlay, and give a written estimate; (2) design & engineering — architectural plans plus structural and Title 24 documentation; (3) permitting — we submit and clear LADBS plan check for you; (4) construction — one accountable crew, a clear schedule and daily site management; (5) final inspection & walkthrough — signed off, cleaned up and warrantied.

Why Woodland Hills Homeowners Choose HomeSense

We are a fully licensed (CSLB #1125001), bonded and insured general contractor with a 5.0-star reputation and 15 years building across the San Fernando Valley since 2011. We are local — headquartered minutes away in West Hills — we design to your lot’s real zoning and hillside limits instead of promising square footage you can’t legally build, and we back every addition with a written workmanship warranty. Explore our nearby work: Encino, Van Nuys, Studio City, Reseda and Northridge additions, our Los Angeles home additions pillar, and everything we build in Woodland Hills — including new construction and roofing — plus our custom home building across Los Angeles. See all service areas.

Frequently Asked Questions

How much does a home addition cost in Woodland Hills in 2026?

Single-story room additions typically run about $275–$605 per square foot — roughly 110% of the LA County average — so a mid-sized 300–400 sq ft addition lands around $105,000–$260,000. Second-story additions run higher at about $400–$700 per square foot because they require structural reinforcement of the existing foundation and framing plus a roof-off phase.

Do I need a permit for a home addition in Woodland Hills?

Yes. Any addition that creates new floor area requires a full LADBS building permit and plan check covering structural, electrical, plumbing and mechanical work. Second-story and hillside additions also require stamped structural engineering, and lots in the Very High Fire Hazard Severity Zone must meet California Building Code Chapter 7A. HomeSense handles the entire submittal and inspection process.

How large an addition can I build on my Woodland Hills lot?

On flat R1 lots north of Ventura Boulevard, the Baseline Mansionization Ordinance caps total floor area at 0.45 of the lot size (up to 0.50 with a design/green bonus) — about 3,600–4,000 sq ft of house on an 8,000 sq ft lot. Hillside RE/RA lots south of the Boulevard are governed by the Baseline Hillside Ordinance, where buildable area shrinks as slope increases. We confirm your exact buildable area before design.

Are additions in the Woodland Hills hills subject to fire-code rules?

Often, yes. Much of hillside Woodland Hills sits in a Very High Fire Hazard Severity Zone within the Wildland-Urban Interface, so additions must use ignition-resistant materials under California Building Code Chapter 7A — Class-A roofing, ember-resistant vents, fire-rated siding and eaves, tempered glazing — plus defensible-space clearance. We build this detailing in from the start.

How long does a home addition take in Woodland Hills?

Plan on about 4–7 months for design and permitting and 5–9 months of construction — roughly 9–16 months total. Hillside and fire-zone lots take longer in plan check because of grading and Fire Department review.

Should I build a home addition or an ADU in Woodland Hills?

Choose an addition when you want the new space connected to your home; choose a detached ADU when you want rental income or a separate unit. California’s 2026 rules are ADU-friendly — SB 1211 allows multiple detached ADUs on qualifying lots and AB 2533 lets owners legalize pre-2020 unpermitted units — so we help you compare both before you commit.

Ready to start? Call or text HomeSense Construction & Remodeling at (818) 300-3422 for a free Woodland Hills home-addition estimate, or reach us on WhatsApp at (818) 266-1292.

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