ADU Builder · Santa Monica
A second home on your Santa Monica lot, permitted through the city’s own Planning and Building review. We handle the whole process.
ADU Builder in Santa Monica
A Santa Monica lot is worth too much to end at the back fence. A permitted ADU can become a rental a few blocks from the beach, a place for your parents, or the office that never fit inside the main house. The catch is the process: Santa Monica reviews ADUs under its own detailed standards, and knowing those standards is where a local team earns its keep.
Athenian Builders Group is a licensed California general contractor (CSLB #1045030) that designs, permits, and builds ADUs across Santa Monica with its own crews. You approve a fixed, itemized price before construction, and every unit carries a written 2-year workmanship warranty. See our full ADU construction services.
Permits
Santa Monica writes its own ADU standards and runs its own review, so permits go through the City of Santa Monica (Planning and Building), not LADBS. We prepare the drawings, file the submittal, and handle plan-check corrections and inspections ourselves.
Transparent Pricing
Real 2026 Los Angeles-area ranges by type. Where you land depends on size, site conditions, and finishes, and we give you a fixed, itemized price after a free on-site visit.
| ADU Type | Typical Size | Typical Cost (2026) |
|---|---|---|
| Garage Conversion | 300–500 sq ft | $100k – $180k |
| Junior ADU (JADU) | up to 500 sq ft | $90k – $160k |
| Attached ADU | 400–800 sq ft | $180k – $320k |
| Detached New-Build | 500–1,200 sq ft | $250k – $450k |
Typical ranges for 2026, not quotes. Financing is available for qualified homeowners. See remodel financing options. Considering a smaller in-home unit? See our Junior ADU page.
Estimated project cost
Why Athenian
Most “ADU builders” are design shops or brokers who sub the construction out. We are a single self-performing team: we design it, pull the permits, and build it with our own crews. That means one point of contact, a fixed itemized price before we start, a firm timeline in writing, and a written 2-year workmanship warranty on everything we build in Santa Monica.
Questions
Yes. We design and build ADUs across Santa Monica, and we take each one through the city’s own planning and building review, from first drawings to final inspection.
Santa Monica is its own city, so the City of Santa Monica issues permits under its own ADU rules, not LADBS. We manage the entire process for you.
It depends on the type and size. A garage conversion typically runs $100k–$180k, while a detached new-build lands between $250k–$450k. You get a fixed, itemized price after a free on-site walkthrough.
Most of our ADUs finish in 3 to 5 months. City review adds time up front, which varies by project, so we give you a firm timeline in writing before construction starts.
Start with a free on-site feasibility visit. We’ll walk your Santa Monica lot, tell you what fits, and put a fixed, itemized price in writing before we ever break ground. Call (310) 857-2520.
Takes about a minute. We reply the same business day and set up a free on-site visit.
