OnePhase Inc: ADU Construction and Development in San Diego
OnePhase Inc is a San Diego-based construction and development company that takes an end-to-end approach to projects — covering feasibility through completion. Their work reflects current trends in San Diego's ADU market, where smaller footprints, conversion-based projects, and incentive-aware planning are increasingly common strategies for property owners looking to add dwelling units.
San Diego ADU activity continues to favor high-efficiency layouts and conversion-based projects. Garage conversions, room additions, and compact detached ADU builds are popular because they typically reduce the scope of site work and can shorten overall field timelines. As an ADU contractor operating in this environment, OnePhase Inc works within these realities when planning and executing projects.
Fee Exemptions and Smart Layout Planning
One consistent planning consideration in California is the 750 square foot threshold. Under California state guidance, ADUs under 750 sq ft are exempt from local impact fees. This can make a meaningful difference to overall project feasibility, and it's a factor that shapes how accessory dwelling unit builders like OnePhase Inc approach layout and design decisions from the outset.
For property owners considering a granny flat, in-law suite, backyard cottage, or Casita, keeping the unit at or under this threshold — where the program allows — is a practical way to manage costs without sacrificing functionality.
San Diego's ADU Bonus Program is another strategic tool available to owners and developers. The City allows additional ADUs to be built in exchange for deed-restricted affordable units (restricted for 15 years). Projects located within Transit Priority Areas (TPAs) may qualify for stronger bonus potential. This structure has become a driver behind multi-ADU site planning and stacked approval strategies where zoning and parcel conditions support it.
Permitting Timelines and the Expedite Option
Permitting is a practical concern for any ADU builder working in San Diego. The City's Development Services Department publishes a weekly permit processing timeline snapshot covering application setup, review, and issuance stages. This kind of visibility is useful for building realistic pre-construction schedules and avoiding incomplete submittals that can cause delays.
For projects where time is a priority, the City also offers an optional Expedite Program for qualifying projects. This can influence how teams approach submittal completeness and consultant coordination from early in the process.
OnePhase Inc's streamlined, end-to-end approach is designed to navigate these layers — from initial feasibility assessment through permitting and construction — for property owners pursuing detached ADU builds, garage conversions, JADU projects, and other accessory dwelling unit types across San Diego.
