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Hills & Canyons Home Additions.

Adding space to an existing LA house is a different project than building from scratch — you are tying into 1920s framing, surveying the lot for setbacks, and protecting an occupied home through the build. We design additions that match the original house, hold the existing roofline, and pass LADBS structural review the first time.

Hill parcels add the Baseline Hillside Ordinance, geotech, and (along the ridgeline) the Mulholland Scenic Parkway Specific Plan to every permit package. The ADU itself is still ministerial, but plan-check takes longer because the structural, grading, and haul-route sheets are heavier than a flat-lot project.

Hills & Canyons cost band — 2026

$400 – $700 / sqft (first-story); $550 – $900 / sqft (second-story)

Foundation work, roof tie-in complexity, and how much of the existing house you have to touch drive the band.

Hills & Canyons permit clock

12–18 weeks ministerial

Plan on 4–6 months for design + LADBS permit, then 5–8 months on-site for a 500–800 sqft addition.

Scope — start to keys.

  • Setback / FAR / hillside check before contracting
  • Architectural design that matches the existing house line
  • Structural tie-in — footings, framing, roof
  • Full MEP extension and panel upgrade if required
  • Finishes, exterior siding/stucco match, paint, landscape repair

What changes about the permit here.

  1. BHO caps height to ~33 ft and limits grading cuts based on lot slope.
  2. Soils / geotech report required on any slope >10%.
  3. Hillside Construction Regulation permits gate haul-route hours and truck size.
  4. Beverly Hills + Bel-Air HOA / R1 design review runs parallel to building permit.

What moves the Hills & Canyons number.

  • Slope-driven foundation work commonly $80–250k above flat-lot equivalent.
  • Crane / pump days run 2–4× a Valley job — narrow streets and switchbacks.
  • Caissons on steep slopes can hit $1,500–4,000 per linear foot of depth.
  • Beverly Hills design review pushes cladding budgets up sharply.

In short.

How much does a home addition cost in Los Angeles?
First-story additions in LA typically run $400–$700/sqft installed. Second-story additions run $550–$900/sqft — they cost more because of the structural work to the floor below.
Can I add a second story to my LA house?
Usually yes, but the existing foundation and first-story framing have to support the load — we engineer the structural retrofit. Hillside Ordinance and view-protection rules can limit height.
Do I need to move out during a home addition?
Not usually. We sequence and dust-protect so the addition tie-in is the last phase. Most of our LA clients stay in the house the whole project.
Does the Baseline Hillside Ordinance kill my ADU?
Almost never. State ADU law overrides local FAR limits up to 800 sqft, and many hillside lots can fit a full 1,200 sqft attached ADU even under BHO.
How much does hillside geotech add?
Plan on $8–25k for the report itself. The downstream cost — caissons, retaining walls, deeper foundations — is where the real budget impact lives.

More we build in Hills & Canyons.

Home Additions in nearby LA areas.

Got a Hills & Canyons project in mind?

Send us the address and we’ll pull Hills & Canyons zoning, setbacks, and home additions feasibility before you spend on drawings.

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