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ADU & Additions · Los Angeles

Add space. Add value.
Add possibility.

Custom accessory dwelling units and room additions designed and built to seamlessly expand what your property can do.

What We Do

Space that works
for you.

An ADU is one of the highest-return investments a Los Angeles homeowner can make — adding rental income potential, family living space, or long-term property value in one well-executed build. Avanti specializes in full-service ADU and addition projects from concept through permit approval to final certificate of occupancy.

Our design-build model means a single team guides your project from the first sketch to the final punch list — no fragmented contractor chains, no miscommunication. We handle zoning analysis, architectural planning, permit submission, and all trades in-house.

Whether you're building a detached backyard cottage, a garage conversion, or a two-story addition, Avanti delivers thoughtfully designed, city-compliant structures built to last.

Modern home addition

What's Included

Our ADU & addition
services.

🏡
New ADU Construction

Detached backyard ADUs and junior ADUs built to LA city code — fully self-contained with kitchen, bath, and living space.

🔄
Garage Conversions

Transform an underused garage into a permitted, livable ADU — one of the fastest and most cost-effective additions available.

📐
Room Additions

Expand your primary living space with a bedroom, family room, or multi-use addition that integrates seamlessly with your existing home.

📋
Permits & Design-Build

Full permit handling, architectural drawings, and city coordination — everything managed by one team so you can focus on the vision.

Why Choose Us

The Avanti
difference.

🏛️

Licensed & Insured

CSLB General Contractor license #1117924 with full coverage. ADU and addition work requires the highest level of licensing — we meet it.

💰

Transparent Pricing

We scope ADU projects in detail before breaking ground so there are zero cost surprises. Our estimates are comprehensive and honest.

"Competitive pricing with no surprises or hidden charges. Professional and efficient."— Lucas Simmons
👤

Roman's Personal Involvement

ADU projects are complex — Roman is personally involved at every design review, permit milestone, and construction phase to keep things on track.

"Roman made every stressful decision easy. He handled so many things so we wouldn't have to."— Mike Purcell

Ready to transform your home?

Let's start with a conversation. No pressure, just possibilities.

Call (310) 878-0700 Get a Free Quote
Written by

Roman Leonelli

Founder & General Contractor · Avanti Construction Group · CSLB #1117924

Roman personally oversees every Avanti project in Los Angeles from first design consultation through final walkthrough. This content reflects his direct experience on active jobsites across LA County — not generic marketing copy.

Read Roman's full bio →

Frequently Asked

Real answers from Roman.

How much does an ADU cost in Los Angeles?

Detached ADUs in LA typically run $250,000 to $500,000 all-in for a 600–1,200 sq ft unit, including design, permits, construction, and utility connections. Garage conversions are usually less ($120,000–$250,000). Junior ADUs (JADUs) within the main house can start around $75,000–$150,000.

How long does it take to build an ADU in LA?

From signed contract to certificate of occupancy, a detached ADU in LA typically takes 6 to 10 months. Design and permits usually take 2–4 months; construction runs 4–6 months. LA's streamlined ADU permit process has improved turnaround versus earlier years.

What permits do I need for an ADU in Los Angeles?

LA allows ADUs by right in most residential zones under state law (SB 9 and local ADU ordinances). You need a building permit, plumbing permit, and electrical permit at minimum. Larger ADUs or those on challenging lots may also need planning approval. We handle all permit pulls.

Can you build an ADU on any LA lot?

Most single-family lots qualify, but setbacks, lot coverage, fire access, and height limits vary by zone. We start with a free feasibility review of your property before any design work, so you know upfront whether an ADU makes sense on your lot.

Can I rent out my ADU?

Yes — ADUs are legal rental units in LA. State law prohibits short-term rentals (under 30 days) for new ADUs, but long-term tenancy is fully allowed. Many clients use ADUs for rental income, family housing, or home offices.