ADU Builder in Concord, CA. Permitted Builds, Local Team.

DevCo Building Enterprises builds permitted ADUs in Concord, CA, including detached backyard units, garage conversions, and attached ADU additions, within a 15-mile radius of our Pacheco headquarters.

Licensed & Insured
Free Estimates
ADUs · Additions · Seismic Retrofit
Modern living room with built-in shelving and cabinets, a stone fireplace with a mounted TV, a dark wooden coffee table, and a light sectional sofa with decorative pillows.

DevCo Building Enterprises is a licensed general contractor based in Pacheco, CA, specializing in ADU construction, home additions, and seismic retrofitting across Contra Costa & Alameda Counties — including Walnut Creek, Lafayette, Orinda, Oakland, Berkeley, and surrounding cities within a 15-mile radius. Owner Devin Grimes leads every project from permit to final walkthrough. Each project has a dedicated Project Manager.

What We Build

We Build What Concord, CA Homeowners Need Most

Whether you're adding an ADU to your backyard, expanding your home's footprint, or bringing a commercial property up to seismic code — DevCo handles the full project. One contractor. One point of contact. No surprises.

ADU Construction

Build a fully permitted accessory dwelling unit on your property. Detached cottages, garage conversions, or above-garage additions. Most Concord, CA ADU projects range $150,000–$350,000 depending on size and finishes. We design, permit, and build.

ADU Additions

Already have a structure? We convert garages, expand existing footprints, or add second-story ADUs. Ideal for homeowners adding rental income or housing family without starting from scratch.

Seismic Retrofitting & Commercial TI

Commercial property owners and investment groups trust DevCo for seismic compliance and tenant improvement projects. We handle permits, structural work, and city coordination.

New Custom Builds

Planning a primary home or new construction on a vacant lot? DevCo brings the same licensed, hands-on approach to new builds across the county.

Why DevCo

Why Concord, CA Homeowners Choose DevCo

Licensed General Contractor

Dedicated Project Manager and team on every project. You're not handed off after the sale.

Straight Talk, No Runaround

We work with homeowners and investors who are ready to build. Real estimate. Clear scope. Realistic timeline.

Hyper-Local — 15-Mile Radius

We stay local. Faster response times, better subcontractor relationships, and a crew that knows the neighborhoods.

Full-Service from Permit to Walkthrough

One contract. One team. No finger-pointing between GCs and subs. DevCo owns the outcome.

Real Projects. Real Results.

As a first-time business owner opening my first bakery, I want to express my sincere gratitude for making the process so seamless.Your team was incredibly hands-on, not only with the construction but also with project management. I particularly appreciated the precise timelines, daily and weekly updates, and your coordination with my corporate team. Additionally, your assistance with the loan approval process was invaluable.I cannot thank you enough for everything you accomplished within such a quick turnaround. I will highly recommend your services to others.
Kevin S.
My home was the one in the job photos. My house was destroyed by water damage from a previous contractor. Devco came in and did what was required to get my family back into our home and more. His crew was amazing. They were very punctual, very hard working and very clean. The were very attentive to our situation and needs. I hope I don't need to use them ever again but if I did, I would hire them in an instant. I have also recommended them to everyone I know who is looking to get work done, from bathroom remodels to whole home rehabilitation
Antonio W.
Devin and team are a breeze to work with. We gave them a 45 day window to finish a refurbishment project for one of our clients. He and his team pulled it off and it was a miracle. They worked late hours and never even complained once about anything a they did what was required. No questions asked!The client is a global client of ours and they nothing but good things to say about Devin and teams professionalism, quality and intensity.We are hiring Devin for another project in Boston as a consultant because of this!Great work, Devin!
Gokul R.
Common Questions

Frequently Asked Questions

How much does an ADU cost in Concord, CA?

Most ADU projects in Concord, CA range from $150,000 to $350,000 depending on size, site conditions, and finish level. A standard detached ADU (400–600 sq ft) typically falls between $180,000–$260,000. DevCo provides free on-site estimates so you know your number before committing.

How long does it take to build an ADU in Concord, CA?

From permit submission to final walkthrough, most ADU projects in Concord, CA take 6–12 months. Permitting alone can take 2–4 months depending on the city and plan complexity. DevCo manages the entire permit process and keeps you updated at every milestone.

Do I need a permit to build an ADU in Concord, CA?

Yes. All ADU construction in Concord, CA requires a building permit. DevCo handles all permit applications, plan submissions, and city coordination as part of our standard service.

What's the difference between an ADU and a home addition?

An ADU is a separate, self-contained living space on your property — its own entrance, kitchen, and bathroom. A home addition expands your existing structure. DevCo builds both, and can help you decide which makes more sense for your property.

Does DevCo handle seismic retrofitting for commercial properties?

Yes. DevCo works with commercial property owners and investment groups across Concord, CA on seismic compliance and tenant improvement projects. If your building needs a soft-story retrofit or structural upgrade, we can assess and quote it.

How do I get started?

Fill out our short estimate request form or call (925) 448-2123. Devin or a team member will follow up within one business day to schedule a free on-site consultation.

Get Started

Ready to Build? Let's Talk.

DevCo serves Concord, CA homeowners and investors who are serious about building. If you're ready to move forward on an ADU, addition, or commercial project — we'll give you a straight answer and a real estimate.

(925) 448-2123
devin@devco.llc
5702 Marsh Dr. Ste. K, Pacheco, CA 94553
Mon–Fri, 8am–5pm