Legalizing an existing accessory dwelling in-law unit in San Francisco

One of our partner architects, David Locicero recently completed the legalization of an existing in law unit in San Francisco.  The process from start to finish lasted 21 months and cost just over $50,000. This is for an existing in-law apartment that needed to be updated to meet current codes.

Do you wonder:

  • Can I legalize an illegal in-law apartment or accessory dwelling in my home?
  • What permits do you need to legalize an unpermitted apartment in your home?
  • What do building permits cost?
  • How long does it take to get permits?
  • How much does it cost to build or legalize an unpermitted apartment?


It’s near impossible to get the answers to these questions from other architects and contractors or neighbors because almost no one has done this. We answers these questions here and this is based on experience, not guesswork!

New Avenue and our network of architects and contractors has more experience than any other company we know of, and we only know of this one project where a typical homeowner legalized an existing in law apartment. We know plenty of unpermitted conversions or additions that can serve as a separate in-law unit.  But we know of just one out of an estimated 30,000-40,000 illegal in laws in San Francisco that was legalized!

Here are the facts about the legalization process:

When did the clients accept the design proposal and hire you: June 2015
When permits were submitted: September 8, 2015 (3 months of design)
When permits were approved: April 2016 (8 months of permit time! Just plan on the same)
Permits: The permit process in San Francisco moves at a glacial pace. Once comments are issued, plans examiners can be very helpful.
Construction started: April 2016
Construction finished:  November 2016 (8 months of construction). However we didn’t get the Certificate of Occupancy until January 2017. Between the holidays, and some confusion among the inspectors, it took us quite a while to get our “CO”. (an additional 2 months of waiting.
# Hours of design time: Approximately 45 hours including responding to plan check comments and construction admin.
We had a very good contractor and very few problems uncovered during construction. The existing conditions were very favorable for minimal design costs.
Other subconsultants needed: Title 24 (Energy Conservation Compliance). I used
Approximate design cost: $5000
Approximate construction cost: $50,000

Total timeline: 21 Months from start to finish.

We can share much more details, copies of the plans, and review your project ideas.  It’s free to call New Avenue if you have any questions.  We offer a $250 design session in your home if you want an assessment of your property.

Here are before and after photos of the living room and bathroom:

sunset inlaw_before_1 sunset inlaw_after_1

Bathroom Before

sunset inlaw_after_3


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