ADU Builder in Santa Clara County

We serve Northern California across three regions: the San Francisco Bay Area, Greater Sacramento, and the Central Valley. Our published guides cover 14 counties and 88 cities. Our Castro Valley and Sacramento offices support local estimating, permit coordination, and project planning across these regions.

Financing may be available for eligible projects with approved credit. Available terms depend on lender approval, project scope, and current programs. Your project manager can review the options that apply before work begins. We also accept checks, ACH, and major credit cards.

Yes. Hamilton Exteriors holds CSLB License #1078806, active general liability coverage, and the required contractor bond. We also hold GAF Master Elite and James Hardie Elite Preferred credentials. We can provide current proof of coverage before work begins.

Permit requirements depend on the project scope and local jurisdiction. Hamilton Exteriors coordinates required applications, plan documents, corrections, and inspections. Permit fees and allowances appear in the proposal before construction begins.

ADU costs in Santa Clara County vary by city — from San Jose to Milpitas. With median home values averaging $2,210,000 across the county, we see a range of project scopes. Hamilton Exteriors provides free, itemized estimates for every Santa Clara County project with no hidden fees.

California's ADU laws make it possible to build on most residential lots in Santa Clara County. Santa Clara County has streamlined the permitting process. We evaluate your property's potential during our free consultation, including setbacks, utility access, and local zoning.

In Santa Clara County, you can build detached ADUs (up to 1,200 sq ft), garage conversions, attached additions, and junior ADUs (up to 500 sq ft). Many homeowners in Sunnyvale are choosing detached ADUs for rental income or multi-generational living.

Santa Clara County is one of California's most ADU-friendly regions. Santa Clara follows state ADU law (AB 68/SB 13) allowing detached ADUs up to 1,200 sq ft, junior ADUs up to 500 sq ft, and garage conversions on most single-family lots — often without additional parking requirements. Santa Clara has also adopted streamlined ADU permits with reduced fees. Hamilton Exteriors handles the full ADU process: design, engineering, permit applications, and construction. Most ADU permits in Santa Clara are approved within 60 days.

Yes. California's Title 24 energy standards apply to all roof and window replacements in Santa Clara and throughout Santa Clara County. For roofing, this means cool-roof-rated materials are required on low-slope roofs and recommended on steep-slope roofs to reduce heat gain. For windows, replacements must meet U-factor and SHGC ratings for Climate Zone 4 (which covers most of Santa Clara County). Hamilton Exteriors ensures every project meets or exceeds Title 24 requirements — we handle the energy calculations and compliance documentation.