What is the 2026 cost range for a single-story addition scope home addition in Los Angeles?

$203,000-$464,000, with the median landing near $333,500. The range reflects finish tier and layout complexity within the single-story addition scope; the Los Angeles labor multiplier of 1.45× vs national median is baked in.

How long does a single-story addition scope home addition take in Los Angeles?

18-26 weeks of on-site construction for the single-story addition scope, plus 8-16 weeks of permit review in Los Angeles if the scope requires a permit. Cosmetic-only refreshes often skip permits; anything touching plumbing, electrical, or structural does not.

What is the single biggest budget-overrun risk for this scope?

Matching old siding or brick — if the material is discontinued, the whole elevation has to be reclad. $8-20K unexpected if not scoped up front.

Home addition — Single-story addition Cost in Los Angeles, 2026

Low

$203K

$203,000

Median

$334K

$333,500

High

$464K

$464,000

Scope timeline: 18-26 weeksLos Angeles permit window: 8-16 weeksUpdated 2026-04-24

Why single-story addition × Los Angeles produces this band

A single-story addition scope for a home addition in Los Angeles combines two price levers: scope and metro labor rates. Single-story additions extend the existing footprint at grade — new foundation section, roof tie-in, and framing that matches the existing structure. No structural work on the original house beyond the tie-in. Against the national median remodel labor rate, Los Angeles runs 45% above the national median — so the single-story addition band comes in at the mid-range, then scales 45% above the national median on top of that. Permit timelines for residential work in Los Angeles typically run 8-16 weeks, which is the window you plan your design and decision sequence against. This page gives you the actual 2026 Los Angeles bands for this exact combination, plus the three cost drivers Baily asks about first when scoping the project live.

What drives cost for a single-story addition scope

·Foundation extension (slab or stem-wall to match existing)
·Roof tie-in flashing and structural connection
·Exterior siding match (often requires whole-elevation repaint)
·HVAC extension into the new zone

What makes Los Angeles different

Labor — CSLB-licensed GC market is constrained post-2025 wildfire demand surge.
Labor — Union framing and electrical rates carry a 25-30% premium over the national median.
Labor — Soft-story and seismic-retrofit inventory competes for the same structural crews.
Material — West Coast port throughput sets lumber and steel pricing — 2025-2026 saw 12-18% swings quarter to quarter.
Material — Title 24 energy requirements push envelope + glazing spec higher than national average.

Los Angeles rules that affect this scope

LADBS plan check runs 8-16 weeks for typical residential remodels; expedite is available for a fee.
Title 24 Part 6 energy code adds insulation, fenestration, and HVAC requirements that add 4-8% to material cost.
LA County Mello-Act applies to coastal coastal-zone demolitions — adds 6-14 weeks for replacement-housing review.
Soft-story retrofit ordinance (LA Ordinance 183893) affects properties with tuck-under parking and adds scope for multifamily work.

Scope your home addition with Baily.

Baily asks the eight questions that determine where your project lands inside the $203K-$464K band for Los Angeles and hands the scoped brief to one licensed builder.

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Questions LA homeowners actually ask

$203,000-$464,000, with the median landing near $333,500. The range reflects finish tier and layout complexity within the single-story addition scope; the Los Angeles labor multiplier of 1.45× vs national median is baked in.