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.

How big can my detached ADU be in the Valley?

State law guarantees up to 1,200 sqft on a single-family lot, regardless of local FAR limits. Most Valley lots can fit a 1,000–1,200 sqft 2BR detached unit.

Do I need a Mulholland Specific Plan review?

Only if your parcel is inside the Mulholland Scenic Parkway Specific Plan boundary — primarily the south-facing ridgeline of Sherman Oaks, Encino, and Tarzana. We check the parcel on the first walk.

San Fernando Valley 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.

The Valley is the most predictable corner of LA city for an ADU permit. Standard R1 lots, flat topography, and LADBS's online portal mean state ADU law applies cleanly with no neighbor notice and no discretionary review. The two variables are the Mulholland Scenic Parkway Specific Plan (south-side hillside parcels) and Very High Fire Hazard Severity Zones.

San Fernando Valley 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.

San Fernando Valley permit clock

6–10 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.

Ministerial review under LAMC §12.22-A,33 — no public hearing.
Detached rear-yard ADUs fit standard 50×150 lots without variances.
VHFHSZ parcels require Chapter 7A ignition-resistant exterior assemblies.
Mulholland Specific Plan parcels need a separate Director's Determination before LADBS.

What moves the San Fernando Valley number.

Most predictable cost in our service area — flat lots, easy crane / concrete access.
Chapter 7A fire-rated assemblies add $18–35k in materials on VHFHSZ parcels.
Mulholland Specific Plan parcels add design + filing fees, not construction cost.
LADWP service drop runs $4–12k depending on existing main panel.

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.
How big can my detached ADU be in the Valley?: State law guarantees up to 1,200 sqft on a single-family lot, regardless of local FAR limits. Most Valley lots can fit a 1,000–1,200 sqft 2BR detached unit.
Do I need a Mulholland Specific Plan review?: Only if your parcel is inside the Mulholland Scenic Parkway Specific Plan boundary — primarily the south-facing ridgeline of Sherman Oaks, Encino, and Tarzana. We check the parcel on the first walk.

More we build in San Fernando Valley.

Home Additions in nearby LA areas.

Got a San Fernando Valley project in mind?

Send us the address and we’ll pull San Fernando Valley zoning, setbacks, and home additions feasibility before you spend on drawings.

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