ADU in Simi Valley - Design, Permits and Build Under One Contract
We handle the design, the engineering, and the city permit, then build it. One contract, one crew, one accountable point of contact. Free feasibility check on your lot before you commit.
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Our ADU Services
From garage conversions and junior ADUs to fully detached guesthouses and complete site prep, we handle every stage of your ADU project under one roof.
ADU Design & Permitting
Professional adu design & permitting service. Licensed & insured with a satisfaction guarantee on every job.
ExploreGarage Conversion ADU
Professional garage conversion adu service. Licensed & insured with a satisfaction guarantee on every job.
ExploreNew Detached ADU
Professional new detached adu service. Licensed & insured with a satisfaction guarantee on every job.
ExploreJunior ADU & Interior Conversion
Professional junior adu & interior conversion service. Licensed & insured with a satisfaction guarantee on every job.
ExploreADU Site Prep & Utilities
Professional adu site prep & utilities service. Licensed & insured with a satisfaction guarantee on every job.
ExploreOur Work in Simi Valley
A look at recent adu projects across Simi Valley and surrounding areas.
An ADU Built the Way Your Home Deserves
Your home is your most important investment, and any addition to your property should reflect that. We bring the same care and pride to every ADU we build - selecting quality materials, hiring skilled tradespeople, and personally overseeing each phase of construction. The result is a structure that looks beautiful, performs reliably, and adds lasting value to your Simi Valley property.
We're not a volume builder churning out identical boxes. Every ADU we design is shaped around your property's character and your family's needs. That personal approach is why so many of our clients in Simi Valley refer us to their neighbors and come back to us when they're ready for their next project.
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No Surprises - Just Honest, Reliable Service
From the very first site visit to the final inspection walk-through, we communicate openly about costs, timelines, and any challenges that arise. We provide clear, itemized proposals so you always know what you're paying for and why. Our clients tell us that what they appreciate most is never having to chase us down for an update.
We've built our reputation in Simi Valley on doing exactly what we say we're going to do. That means staying on schedule, respecting your property, keeping the job site clean and organized, and delivering a finished ADU that matches - or exceeds - what we showed you in the design phase.
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What Homeowners Say
Projects across Simi Valley and surrounding communities.
"The rental income has covered the payment since the second month. They were realistic about the numbers rather than optimistic."
"Every allowance was itemised at the start, so the finish selections did not turn into a surprise at the end."
"The permit set and the build were one contract with one number. Our neighbours used two firms and spent a year watching them blame each other."
"They walked us through setbacks and utility capacity before we paid anything, and told us one of our two options was not going to get approved."
"Detached unit in the back garden. Good design, good build quality, and the cost changes were documented and agreed in advance."
Your ADU, Done Right - From Day One
Our proven eight-step process keeps your project on schedule, on budget, and stress-free from the very first conversation to the day you hand over the keys.
Free Discovery Call
We start with a friendly, no-pressure conversation to learn about your goals, your property, and your timeline. No jargon - just honest answers about what's possible for your Simi Valley home.
Site Evaluation & Feasibility
Our team visits your property to assess setbacks, utilities, soil conditions, and zoning requirements. You'll walk away knowing exactly what your lot can support before spending a dime.
Custom ADU Design
Our designers craft a floor plan tailored to your lifestyle, your budget, and your property's unique character. We refine every detail until the design feels completely right to you.
Permit Package Preparation
We prepare a complete, city-ready permit application - including structural drawings, energy calculations, and Title 24 compliance - so approval moves as quickly as possible.
City Permitting & Approvals
We submit directly to the City of Simi Valley and manage all correspondence with the building department, keeping you informed at every milestone so there are no surprises.
Site Prep & Utility Connections
Once permits are in hand, we prepare the site, coordinate grading if needed, and establish water, sewer, and electrical connections sized correctly for your new ADU.
Construction & Craftsmanship
Our experienced crews build your ADU with the same attention to detail we'd bring to our own homes - clean framing, quality finishes, and workmanship you'll be proud of for decades.
Final Inspection & Handover
We schedule and pass all final city inspections, walk through the completed ADU with you, and make sure every last detail meets your expectations before we hand over the keys.
Built to a Higher Standard, Every Time
We measure our success not just in square footage delivered, but in the quality, durability, and livability of every ADU we build.
Code & Zoning Mastery
We know Simi Valley's municipal code inside and out, so your ADU is designed right the first time and sails through plan check without costly revisions.
Permit-Ready Drawings
Every design package we submit is thorough, accurate, and formatted exactly how the city expects it - minimizing back-and-forth and keeping your timeline on track.
Thoughtful Space Planning
We design ADUs that feel spacious and functional well beyond their square footage, making smart use of every corner so your guests or tenants genuinely love living there.
Quality Craftsmanship
From foundation to roofline, we use quality materials and employ skilled tradespeople who take pride in their work - because shortcuts now become expensive problems later.
Utility & Site Expertise
We coordinate water, sewer, gas, and electrical connections with precision, avoiding the costly utility surprises that can derail ADU projects on tricky lots.
On-Time Project Delivery
We set realistic schedules, communicate proactively, and hold our subcontractors accountable so your ADU is finished when we said it would be - not months later.
Why Simi Valley Builds With Us
Simi Valley homeowners choose us because we combine fast, reliable execution with the personal attention and honest communication that a project this important demands.
Faster Permit Approvals
Our deep familiarity with Simi Valley's permitting process means we prepare complete, accurate applications the first time - dramatically reducing the back-and-forth that slows most ADU projects down.
Local Experts You Can Trust
We live and work in this community. We know the neighborhoods, the inspectors, and the city's expectations - and we've built that knowledge into a process that consistently delivers results for our neighbors.
One Team, One Responsibility
Design, permitting, site prep, and construction all flow through one accountable team. You have a single point of contact and never get caught in the middle of finger-pointing between contractors.
Craftsmanship We Stand Behind
We warranty our work and stand behind it because we build every ADU with genuine pride. When you walk through the finished space, we want you to feel it was worth every penny.
Frequently Asked Questions
Honest answers to the questions Simi Valley homeowners ask us most before starting their ADU project.
Ready to Add an ADU to Your Simi Valley Home?
Let's talk about your property, your goals, and your timeline - completely free, with no obligation. Our team is ready to show you exactly what's possible and give you an honest path forward.
(820) 444-6584Get Your Free ADU Consultation
Tell us a little about your project and we'll reach out promptly to schedule your free, no-pressure site evaluation.
ADU Service Across the Simi Valley Area
We Are the Simi Valley Team for Ellery.
Ellery was founded in 2015, the year California's ADU law changed and the permitting queue became the actual product. It is a design-build studio rather than a contractor: the drawings, the permit set and the build are one contract with one price, because the ADU projects that go wrong are almost always the ones where the designer and the builder can each blame the other.
Same training, same parts, same pricing practice, and the same 365-Day Done Right Promise - delivered by people who live here.
Visit Ellery →Part of the Haven Family.
Haven is a family of home-service brands held to one written standard, and Ellery is the adu company in it. One promise stands behind every trade, in every town.