What is the 2026 cost range for a interior conversion scope adu in San Francisco?

$139,500-$294,500, with the median landing near $217,000. The range reflects finish tier and layout complexity within the interior conversion scope; the San Francisco labor multiplier of 1.55× vs national median is baked in.

How long does a interior conversion scope adu take in San Francisco?

14-20 weeks of on-site construction for the interior conversion scope, plus 10-26 weeks of permit review in San Francisco 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?

Existing slab without a vapor barrier — vapor-pressure moisture leads to flooring failure and mold if not re-poured or sealed. Adds $4-8K.

ADU — Interior conversion Cost in San Francisco, 2026

Low

$140K

$139,500

Median

$217K

$217,000

High

$295K

$294,500

Scope timeline: 14-20 weeksSan Francisco permit window: 10-26 weeksUpdated 2026-04-24

Why interior conversion × San Francisco produces this band

A interior conversion scope for a adu in San Francisco combines two price levers: scope and metro labor rates. Interior-conversion ADUs repurpose an existing enclosed space (attached garage, basement) without adding foundation or framing footprint. Faster and cheaper than a detached build. Against the national median remodel labor rate, San Francisco runs 55% above the national median — so the interior conversion band comes in 50% below the mid-range, then scales 55% above the national median on top of that. Permit timelines for residential work in San Francisco typically run 10-26 weeks, which is the window you plan your design and decision sequence against. This page gives you the actual 2026 San Francisco bands for this exact combination, plus the three cost drivers Baily asks about first when scoping the project live.

What drives cost for a interior conversion scope

·Insulation and conditioned-space HVAC tie-in
·Egress window cutting and well install
·Kitchen and bath rough-ins (often net-new to the space)
·Legal separation from the primary unit

What makes San Francisco different

Labor — Bay Area CSLB-licensed contractor scarcity keeps labor rates the highest in California.
Labor — Union framing and electrical rates carry a 30-35% premium over national median.
Labor — Tech-sector remodel demand (Noe Valley, Pacific Heights, Sea Cliff) competes for premium-finish crews.
Material — Victorian + Edwardian heritage restoration uses specialty millwork and painters — significant premium.
Material — Title 24 energy code same as rest of CA — envelope + glazing premium.

San Francisco rules that affect this scope

SF DBI permit process is notably long (10-26 weeks typical; discretionary review on most kitchen/bath >$25K).
Section 317 (Residential Demolition) controls ADU and addition work — lot merger and demolition ratio tracked.
Historic Preservation Commission review for Articles 10 + 11 properties adds 8-16 weeks.
Soft-story retrofit ordinance (SF Ordinance 66-13) affects multi-family properties with tuck-under parking.

Scope your adu with Baily.

Baily asks the eight questions that determine where your project lands inside the $140K-$295K band for San Francisco and hands the scoped brief to one licensed builder.

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Questions LA homeowners actually ask

$139,500-$294,500, with the median landing near $217,000. The range reflects finish tier and layout complexity within the interior conversion scope; the San Francisco labor multiplier of 1.55× vs national median is baked in.