The Bay Area's ADU Builder — Licensed. Local. Done Right.
From ADU construction to seismic retrofitting - DevCo Building Enterprises is the licensed general contractor Bay Area homeowners call first.
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.
We Build What Contra Costa & Alameda 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 Contra Costa 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 Contra Costa Homeowners Choose DevCo
Licensed General Contractor
Dedicated Project Manager and team on every project. You're not handed off after the sale.
ADU Specialists
We serve the Contra Costa and Alameda Counties — Walnut Creek, Lafayette, Orinda, Oakland, Berkeley. Permit-to-finish planning departments — so you don't have to.
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.
Featured Projects
A look at recent ADU builds, additions, and retrofits completed across Contra Costa County.
Real Projects. Real Results.
Serving Contra Costa County — From Pacheco Outward
DevCo Building Enterprises is based in Pacheco, CA and serves homeowners, property managers, and commercial investors within a 15-mile radius.
Have a project outside our radius? Call us at (925) 448-2123 and we're always happy to point you in the right direction.
Frequently Asked Questions
Most ADU projects in Contra Costa County 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 $360,000–$520,000. DevCo provides free on-site estimates so you know your number before committing.
From permit submission to final walkthrough, most ADU projects in Contra Costa County 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.
Yes. All ADU construction in California — including Concord, Martinez, Walnut Creek, and Pleasant Hill — requires a building permit. DevCo handles all permit applications, plan submissions, and city coordination as part of our standard service.
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.
Yes. DevCo works with commercial property owners and investment groups across Contra Costa County on seismic compliance and tenant improvement projects. If your building needs a soft-story retrofit or structural upgrade, we can assess and quote it.
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.
Ready to Build? Let's Talk.
DevCo serves Contra Costa County 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.