This project transformed a 7,800 sq ft San Jose lot from a single 1-bedroom home into FOUR independent, fully rentable units. Apex Homes delivered three pieces of work in parallel: a full remodel of the existing 744 sq ft main house, the formal title change converting that main house into an ADU, and a new detached 749 sq ft 2 Bed / 2 Bath ADU built turnkey at the rear of the lot. In the future, a 2 story duplex will be add to the lot.
For an investor, this is a useful playbook for small-lot San Jose property: an existing modest home doesn’t have to stay the ‘main house.’ California ADU law allows an existing single-family residence to be reclassified as an ADU through a separate permit and title-record change — which effectively frees up the lot’s primary-residence entitlement for future development.
The 749 ADU itself was built on our existing standard floor plan, a refined design that’s already permit-tested in San Jose. Working from a known plan kept the build fast and predictable, with a 5-month construction window and no mid-project changes.
Two Independent Income Units: One detached new ADU plus a converted-and-remodeled existing main house, each fully separate and individually rentable on a single 7,800 sq ft lot.
Apex Homes Standard 749 Floor Plan: Built on our 749 sq ft 2 Bed / 2 Bath our most popular, ROI-driven pre-approved floor plan.
Main House Remodel + ADU Title Conversion: Existing 744 sq ft main house fully remodeled and formally reclassified as an ADU through a separate permit and title-record change.
Can I convert my existing house into an ADU so I can build something new on the lot?
In many cases, yes. California ADU law allows an existing single-family residence to be reclassified as an ADU through a separate permit and title-record change — a planning maneuver that frees the lot's primary-residence entitlement for future development.
The strategy works well on small lots where the existing home is modest. Once the existing house is on record as an ADU, the lot can support a new primary structure (a larger home, or in some jurisdictions a duplex), while the existing house keeps generating rental income.
The catch: the existing structure has to meet ADU requirements (or be brought up to them through remodel), and not every city has a clean process for this. A feasibility study early on is the cleanest way to confirm it's possible on your lot.
How many dwelling units can a single residential lot in California support?
More than most owners realize. On a lot zoned single-family, California ADU law typically allows: the primary residence plus one detached ADU plus one junior ADU (JADU) inside the primary structure. That's up to 3 dwelling units.
But the most underused move is reclassifying the existing primary residence itself as an ADU through a separate permit and title-record change. That frees the lot's primary-structure entitlement for new construction — which, on the right lot, can mean adding a larger new home or even a future duplex while the original house keeps generating rental income.
That's how a 7,800 sq ft San Jose lot with a single 1-bedroom home ends up positioned to support multiple income units. Our 749 sq ft 2B2B at San Jose 95116 was built as part of exactly this kind of multi-unit transformation.
What's the difference between a new ADU and converting an existing structure into an ADU?
Both result in a permitted, code-compliant ADU. The difference is what you're starting from, and what each optimizes for.
A new build starts from a blank site. You get full design control, current-spec materials and systems throughout, and the unit is brand-new from the foundation up. Construction usually runs 4–6 months on site, plus pre-construction permitting. Best when you want a specific layout, finish level, or floor plan optimized for rental appeal.
A conversion takes an existing structure (a garage, a guest house, or even the main house itself) and brings it up to ADU code. It's often faster and cheaper than new construction, since you're reusing existing framing, foundation, and roof. The trade-off is less design flexibility — you're working within what already exists.
Our 749 sq ft 2B2B in San Jose was built as a brand-new detached ADU alongside exactly this kind of main-house-to-ADU conversion on the same lot.
You’ve seen what’s possible—now let Apex Homes handle the details. From initial concept to precision construction, we build custom homes tailored perfectly to your lifestyle and future goals.
