Computed from 2,337 recent building-permit filings in Los Angeles, CA — what people actually declared, not survey guesses.
✓ Verified from 2,337 recent building-permit filings in Los Angeles, CA
Every filing behind this range declared a residential renovation cost between $1,000 and $2,000,000 — outliers and commercial-scale projects are excluded. We only publish a range once at least 30 qualifying filings exist for a city/project combination; this one has 2,337.
Data refreshed September 2026
The short answer: a typical home addition / extension in Los Angeles costs around $75,000, with half of all projects landing between $40,000 and $140,000. If a quote falls well outside that range, it isn't automatically wrong — but it deserves an explanation you can understand.
California's Title 24 energy code and LA's seismic retrofit requirements both apply to qualifying remodels, which is a real source of added scope not present in most other US cities.
Mild, dry weather keeps outdoor and roofing work less seasonal here than in colder or wetter cities, so timing has less effect on price than in Chicago or Seattle.
The middle half of the published sample spans $40,000 to $140,000. That is a 133% spread around the median, so the details of your scope matter more than the label on the project.
An addition or extension can include foundations, structure, roof tie-in, envelope, services, and interior finishes for the new space.
Land purchase, temporary accommodation, major utility upgrades, furnishings, and redesign after approval are commonly outside the filing value.
This guide is based on 2,337 qualifying permit filings, not completed projects. Permit values reflect what applicants declared and can differ from the final paid cost.
Every figure on this page is computed from declared valuations on building permits filed with the Los Angeles Department of Building and Safety (LADBS), published via the Los Angeles GeoHub open-data portal. We report the 25th percentile, median and 75th percentile of 2,337 recent residential filings — never a single-point "average". Declared values are what applicants file, not final invoices, so treat the range as planning guidance rather than a quote. Full methodology →
The source dataset is maintained by the Los Angeles Department of Building and Safety (LADBS). The published sample is the subset classified as residential, matched to this project type, and carrying a declared valuation from $1,000 to $2,000,000. The count above is the number of qualifying filings used for this city and project, not the number of homes or completed invoices.
Open the Los Angeles GeoHub open-data portal datasetBased on 2,337 recent building-permit filings with the Los Angeles Department of Building and Safety (LADBS), the median declared cost is $75,000. Half of all projects fall between $40,000 and $140,000.
No. Permit valuations are what applicants declare to the Los Angeles Department of Building and Safety (LADBS) when filing, not final invoices — and the Los Angeles Department of Building and Safety (LADBS) doesn't independently verify the declared value. Treat the range as planning guidance and a sanity-check against the quotes you receive, not a price to hold a contractor to.
California's Title 24 energy code and LA's seismic retrofit requirements both apply to qualifying remodels, which is a real source of added scope not present in most other US cities. That local variation is on top of the usual differences in size and specification, which is why we publish the 25th percentile, median and 75th percentile instead of a single misleading "average" — you can see where a quote sits in the real distribution.
Planning something else, or somewhere else? Request a city or project — requests decide what we ingest next.