ADU Design & Architecture

We serve Northern California across three regions: the San Francisco Bay Area (six counties from Alameda to Santa Clara), Greater Sacramento (Sacramento out to Roseville, Folsom, and Davis), and the Central Valley (Stockton to Modesto). Our crews are based in Castro Valley. We handle permits and know the building codes for each jurisdiction, which matters because requirements and fees vary significantly between cities.

We offer $0-down financing with approved credit, 12-month same-as-cash plans, and extended terms up to 15 years for larger projects. You only pay for completed, inspected work — we never ask for full payment before the job is done. Your project manager will walk you through every option during your estimate appointment. We also accept checks, ACH, and all major credit cards.

Yes. CSLB License #1078806 — verify it anytime at cslb.ca.gov. We carry $2M general liability, full workers’ comp, and are bonded per California law. We hold GAF Master Elite, Owens Corning Preferred, CertainTeed ShingleMaster, and James Hardie Elite Preferred certifications — each requires annual training and quality audits to maintain. We’re happy to provide proof of insurance before any work begins.

Most exterior projects in Northern California require a building permit. Fees vary by city — Oakland runs $200–$600, Peninsula cities often more. We handle the entire permit process: application, plan submission, and scheduling inspections. Permit fees appear as a separate line item in your estimate so you’ll see every cost upfront. For homes in WUI fire zones (Berkeley Hills, Oakland Hills, parts of Marin), we ensure full compliance with local fire-rated material requirements.

California requires stamped architectural and structural engineering drawings for ADU building permits. Our licensed architects handle the complete design package as part of our design-build contract, including floor plans, elevations, structural details, MEP coordination, and Title 24 energy compliance calculations.

Our standard design timeline runs six to eight weeks from site survey to permit-ready construction documents. Schematic design takes two weeks, design development with client revisions takes two weeks, and construction documents with engineering take two to four weeks. Rush timelines are available for straightforward projects.

For lots under 5,000 square feet, a studio or one-bedroom ADU between 400 and 600 square feet typically works best. Open-concept floor plans with a combined living-kitchen area, one full bathroom, and built-in storage maximize usability. We also evaluate garage conversions and attached ADUs when detached placement is constrained.

Yes. California law (Government Code Section 65852.2) requires that ADUs include a full kitchen with a sink, cooking appliance, refrigerator, and food preparation counter. Our designs accommodate either compact 24-inch appliance suites for studios or standard full-size appliances for larger units.

We model the ADU alongside your main house in 3D design software, testing siding materials, roof pitch, window proportions, trim profiles, and color palettes for visual consistency. Several Bay Area cities, including Berkeley and Palo Alto, have design review requirements that evaluate this continuity.

State law caps detached ADUs at 1,200 square feet for properties with a single-family home. Attached ADUs can be up to 50 percent of the primary dwelling's floor area or 1,200 square feet, whichever is less. Some cities, like San Jose, permit larger units on qualifying lots. Our architects verify the maximum for your specific property during the feasibility study.

Yes. We frequently design ADUs with Universal Design and ADA features: zero-threshold entries, 36-inch doorways, roll-in showers, roll-under sinks, grab bar blocking, and lever hardware. These accommodations add roughly 3 to 5 percent to construction costs and are increasingly popular for aging-in-place and multigenerational living.

We orient primary living spaces toward southern and western exposures, use clerestory windows in vaulted ceilings, and place operable windows on opposing walls for cross-ventilation. Our designs exceed Title 24 glazing minimums by 30 to 50 percent. In coastal areas like Pacifica and Daly City, we prioritize east-facing windows to capture morning sun.

A detached ADU is a standalone structure separate from the main house, offering maximum privacy and flexible placement on the lot. An attached ADU shares at least one wall with the primary home, which typically reduces construction costs by 10 to 15 percent since it uses existing foundation and utility connections. We evaluate both options during the feasibility study.

Yes, where local zoning allows. Two-story ADUs maximize livable space on smaller footprints and are particularly effective on narrow lots in cities like Oakland and San Francisco. We place bedrooms upstairs for privacy and use the ground floor for living areas. Height limits vary by city, typically 16 to 25 feet depending on lot size and proximity to property lines.

Our complete design package includes site plans, floor plans, exterior elevations, building sections, roof plans, electrical layouts, plumbing schematics, structural engineering, Title 24 energy calculations, and 3D renderings. This constitutes the full construction document set required for permit submission and construction.

Design and engineering costs are included in our design-build contracts. As an integrated design-build firm, we do not charge separate architecture fees. Standalone design services for clients who plan to build with another contractor are available, with pricing based on unit size and complexity.

California law allows both a standard ADU and a Junior ADU (JADU) on a single-family lot. A JADU is up to 500 square feet and must be created within the existing primary home or an attached garage. Our architects can design both units as a coordinated project, maximizing your property's rental income potential.

Sloped lots require specialized foundation design, typically stepped or pier-and-grade-beam systems, and careful grading plans for drainage. Our engineers evaluate soil conditions and slope grades during the feasibility study. Bay Area hillside properties in cities like Oakland Hills, Berkeley Hills, and Mill Valley often need retaining walls and custom foundation engineering.