ADU Construction & Home Additions in Martinez, California
DevCo Building Enterprises is a licensed general contractor serving homeowners and property investors in Martinez, California, specializing in ADU construction, home additions, ADU garage conversions, and seismic retrofitting. ADU projects in Martinez typically range from $150,000 to $350,000 for detached builds, and from $80,000 to $180,000 for garage conversions, with most projects taking 6 to 12 months from permit to completion. Owner Devin Grimes leads every project personally. Call (925) 448-2123 for a free Martinez estimate.
Services We Provide in Concord
ADU Construction
Detached cottages, backyard ADUs, new ground-up builds
ADU Additions
Garage conversions, above-garage additions, existing structure conversions
Seismic Retrofitting
EBB, ESS, and EMR state program certified
Home Additions
Room additions, master suites, second-story additions
Why Martinez Homeowners Choose DevCo
DevCo is not a franchise or a national ADU company operating in Martinez remotely. We are a Pacheco-based contractor - 15 minutes from most Martinez neighborhoods - with owner Devin Grimes on every project. We know Contra Costa County permit departments, city setback rules, and local subcontractor relationships because we have been working in this area, not calling into it.
Martinez is the county seat of Contra Costa County and home to a mix of Victorian-era homes, 1950s ranch houses, and newer construction in the Alhambra Valley. The Calaveras and Concord-Green Valley faults run near Martinez, making seismic retrofitting a meaningful consideration for older wood-frame homes in the area. DevCo is located in Pacheco, directly adjacent to Martinez - we are one of the closest contractors to this market.
Featured Projects
A look at recent ADU builds, additions, and retrofits completed across Martinez, CA.
Real Projects. Real Results.
Frequently Asked Questions
ADU construction in Martinez typically ranges from $150,000 to $350,000 for detached builds depending on size, site conditions, and finish level. Garage conversion ADUs are typically 30 to 50 percent less expensive. City of Martinez Building Division processes ADU applications. DevCo provides free on-site estimates with detailed line-item breakdowns.
Yes. All ADU construction in Martinez requires a building permit. California state law requires the city to process complete applications within 60 days. City of Martinez Building Division processes ADU applications. Martinez is the county seat - building department is familiar with Contra Costa County-wide ADU regulations. Plan check typically 6 to 10 weeks. DevCo handles all permit applications, plan submissions, and city coordination on every project.
DevCo Building Enterprises is a licensed general contractor based in Pacheco, CA, serving Martinez and surrounding Contra Costa communities. Owner Devin Grimes leads every project from permit to final walkthrough. DevCo is also an approved contractor for California's EBB, ESS, and EMR seismic programs.
From permit submittal to final inspection, most ADU projects in Martinez take 6 to 12 months. Permitting adds 6 to 16 weeks depending on plan complexity. DevCo manages the full permit process and provides milestone updates throughout the build.
Yes. DevCo is approved for California's EBB, ESS, and EMR seismic programs and serves Martinez homeowners and property owners with seismic retrofit projects. The Concord-Green Valley and Calaveras faults run through the Martinez area, making seismic safety a relevant consideration for older homes. Call (925) 448-2123 for a free seismic assessment.
Get a Free Martinez Estimate
Call (925) 448-2123 or fill out the estimate form at devco.llc/contact. We respond within one business day and schedule on-site consultations within 48 to 72 hours for Martinez and surrounding Contra Costa communities.