San Jose, South Bay & Peninsula · License #604513
ADU design and construction in San Jose
Lewis & Proveaux designs and builds detached ADUs, attached ADUs, and garage conversions in San Jose and the surrounding South Bay and Peninsula communities. Bring planning, permit coordination, and construction together with one team, starting with your property and the way you want to use the space.
Discuss your projectDetached ADU, attached ADU, or garage conversion?
A detached ADU creates a separate building in the backyard. An attached unit shares part of the existing house. A garage conversion adapts existing space, but the condition of the structure and utilities can affect how much work is needed. We help connect the layout to the property and your priorities.
Plan the house and backyard together
Access, privacy, daylight, outdoor space, utility connections, and the relationship to the main home all affect a useful ADU design. Bring existing drawings, a survey if you have one, and photographs of the property to the initial conversation.
From feasibility to the final walkthrough
Our design-build work connects planning, permit coordination, construction, and finishing decisions. Confirm the proposed scope and site constraints before relying on a concept or budget. The online ADU planner is a starting point for discussion, not an approved construction drawing.
What affects an ADU budget?
Size is only one factor. Foundation work, utility routes, access for construction, structural alterations, and finish selections also matter. A site-specific proposal should explain inclusions, exclusions, assumptions, and allowances so you can compare options fairly.
Separate planning time from construction time
An ADU schedule includes property review, design decisions, permit review, material preparation, construction, and inspections. The time required depends on the site and scope. Discuss the milestones, which decisions need your input, and what could change the schedule before setting a move-in date.
Compare proposals for the same scope
Ask what is included for design, engineering, permit coordination, site preparation, utilities, construction, and finishes. Identify agency fees, allowances, exclusions, and owner-supplied items separately. Comparing a complete scope makes differences between proposals easier to understand.
Prepare for your first ADU consultation
Share the property location, photographs, available drawings or surveys, intended use, budget expectations, and preferred timing. Note access constraints and any existing structures you hope to keep. You do not need a finished floor plan to begin; a property review helps establish which ideas are worth developing.
Local planning resources
Check the current guidance for your property's jurisdiction before relying on a concept. Properties outside San Jose follow their own local review process.
Serving the South Bay and Peninsula
We serve San Jose, Atherton, Campbell, Cupertino, East Palo Alto, Los Altos, Los Altos Hills, Los Gatos, Menlo Park, Monte Sereno, Mountain View, Palo Alto, Portola Valley, Santa Clara, Saratoga, Sunnyvale, Woodside. Share your property location and project goals to start a consultation.
Questions before you begin
01Can you convert my garage into an ADU?+
Lewis & Proveaux works on garage conversions. Whether a particular garage is suitable depends on its structure, foundation, access, utilities, and applicable requirements. A conversion should be evaluated before assuming it will be simpler or less expensive than a new detached unit.
02Do you handle ADU design and permits?+
Our design-build approach connects planning, permit coordination, construction, and finishing decisions. Confirm the design deliverables, engineering responsibilities, agency fees, and permit scope in your project proposal.
03Can I use the online planner before contacting you?+
Yes. The preliminary ADU planner helps you explore a concept and organize preferences for a consultation. Its layouts and estimates are starting points; they are not site-verified construction drawings, permit approvals, or a contractor proposal.
04Do you build ADUs outside San Jose?+
We serve the South Bay and Peninsula communities listed on this page. Share your property location so we can confirm project fit and identify the appropriate local review process.
Ready to take the next step?
Share what you are considering and where the property is located. We will help you understand the next practical step.