đź•’ How Long Does It Take to Build an ADU in Los Angeles?
Introduction
If you’re thinking about building an Accessory Dwelling Unit (ADU) in Los Angeles, one of the first questions you’ll have is:
“How long will it take?”
While the idea of adding a rental or family unit to your property is exciting, it’s important to have realistic expectations about design, permitting, and construction timelines.
At Nail & Hammer Construction Corp, we guide homeowners through the full ADU process — so here’s a breakdown of what to expect at each stage, from concept to completion.
⏳ Average ADU Timeline in Los Angeles
The average ADU project takes 6 to 12 months to complete, depending on the scope, site conditions, and permitting requirements.
Here’s a typical breakdown:
PhaseDurationWhat Happens1. Design & Planning1–2 monthsFeasibility review, floor plan development, and cost estimation.2. Permitting & Plan Check2–4 monthsSubmit plans to LADBS for review and approval.3. Construction Phase4–6 monthsSite work, framing, rough-ins, finishes, and final inspection.
Each project is unique — a simple garage conversion can be done in 5–6 months, while a custom detached ADU may take closer to a year.
🏗️ Step-by-Step Breakdown
1. Design & Feasibility (1–2 Months)
The process starts with:
Site evaluation: Reviewing lot size, setbacks, and zoning requirements.
Architectural design: Creating detailed floor plans and elevations.
Budget alignment: Adjusting design to fit your investment goals.
If you use one of Los Angeles’s pre-approved “Standard ADU Plans”, this stage can move faster and save money on architectural fees.
2. Permitting & Approvals (2–4 Months)
This is where many projects experience delays. Every ADU in Los Angeles must go through the Department of Building and Safety (LADBS) for review.
Typical steps include:
Zoning review
Building & safety plan check
Structural and energy (Title 24) compliance
Corrections and resubmissions (if required)
Pro Tip: Working with a contractor experienced in ADU permitting can shorten approval times dramatically. Nail & Hammer Construction handles all submittals and coordination for clients.
3. Site Preparation (2–4 Weeks)
Before building begins, we prepare the property by:
Clearing the site and setting up temporary fencing
Trenching for new plumbing and electrical lines
Laying foundations or slabs (for detached ADUs)
Garage conversions usually skip the foundation stage, which saves both time and money.
4. Construction (4–6 Months)
The construction phase includes:
Framing and structural work
Electrical, plumbing, and HVAC installation
Insulation, drywall, and finishes
Kitchen, bathroom, and fixture installation
Our team at Nail & Hammer follows a strict construction schedule to minimize downtime and keep inspections on track.
5. Final Inspections & Certificate of Occupancy (2–4 Weeks)
Once construction wraps up, LADBS conducts final inspections for:
Structural integrity
Electrical and plumbing compliance
Energy efficiency (Title 24)
Fire safety and egress
After all inspections pass, you’ll receive your Certificate of Occupancy (C of O) — making your ADU fully legal for living or renting.
⚡ What Can Delay an ADU Project?
Even with a great team, some factors can impact your timeline:
Permit resubmissions or zoning corrections
Unexpected site conditions (old plumbing, poor soil, etc.)
Utility connection delays (DWP scheduling)
Custom designs or finish changes mid-project
Tip: Sticking to your approved plans and selections is the best way to avoid timeline overruns.
📆 Realistic Example Timelines
ADU TypeAverage DurationDescriptionGarage Conversion5–7 monthsFastest option; reuses existing structure.Attached ADU6–9 monthsModerate timeline; shares wall with main home.Detached ADU8–12 monthsLongest timeline; full foundation and utilities.
🏡 How to Stay on Schedule
Hire a licensed general contractor with ADU experience in LA.
Finalize design decisions early.
Use pre-approved plans where possible.
Stay proactive with communication and site access.
At Nail & Hammer Construction Corp, our streamlined process helps clients move from idea to completion efficiently — without cutting corners.
Conclusion
Building an ADU in Los Angeles typically takes 6 to 12 months, but smart planning, experienced contractors, and clear communication can keep your project on track.
Whether you’re converting a garage or building a new backyard unit, Nail & Hammer Construction Corp is here to guide you through every phase — from permitting to move-in.
đź“ž Call 424-800-3704 today to schedule your free ADU consultation and start planning your project timeline with confidence.
