ADUs
Plan an ADU in San Diego County.
Detached, attached, garage conversion and junior ADUs, planned, permitted and built by a licensed San Diego contractor.
ADU overviewADU types
Plan your ADU
Services
Three practices, one team.
ADUs, remodels and additions, and custom homes, designed and built across San Diego County.
All servicesRemodeling and additions
Custom homes
How we work
Resources
Tools and guides for planning your project.
Free calculators, permit guides and the local rules, for building in San Diego County.
All resourcesAbout
Why choose BHI Builders.
A licensed San Diego County builder of ADUs, remodels and custom homes since 1997: who we are, what clients say, and how we work.
About us
Custom homes in San Diego County
We build new and replacement homes on lots across San Diego County, starting with what the site allows.
BHI Builders, a California general building contractor licensed since 1997 (CSLB 738313), builds custom homes on San Diego County lots, among them a 5,852 sq ft courtyard home and a three-story home on a steep hillside lot, both in Black Mountain Ranch.
Book a call before the lot closes, and we read the site with you.
The honest answer
Four lines, written plainly: who this suits, what we take on, what shapes the scope and the schedule, and what to bring to a first conversation.
Before you buy the lot
Most of what a custom home can be is settled by the lot before an architect draws a line: what the zone allows, how steep it is, what the soils will carry, how the utilities reach it and which agency reviews it.
Send us the listing before you close and we read it with you. We point out what the public records show and what only a survey, a soils report or a site visit can settle.
Scope and fit
The rules are the City of San Diego's; the 17 other cities and the County apply their own, and the finder below opens each authority's page.
Everything a custom home includes
What BHI does at each stage of a custom home, so you know who carries each part of the work.
The lot, the rules and the brief.
The drawings made buildable.
One builder on site through every trade.
The house handed over with its record.
Our custom homes
Both built by BHI in the City of San Diego, each with its own page: the photographs, the permit record and the build.
Custom home around a courtyard5,852 sq ft, four bedrooms and five and a half baths around a paver courtyard. Permit issued April 2008, about four months after the application.
Custom home with a stone towerThree stories and seven bedrooms on a steep hillside lot, reviewed under the City's environmentally sensitive lands rules. Completed 2007.These come from the public permit record under BHI's license, 738313. Ask about any of them on a call.
Hillside, coastal and fire-zone lots
Each of these adds a review before the permit, and each changes the design. These are the City of San Diego's rules.
Steep hillsides are land with a natural slope of 25 percent or more and at least 50 feet of rise, or 200 percent and 10 feet. If any part of a lot meets that test, the rules apply to the whole premises, and the listed projects need a Neighborhood or Site Development Permit. Our stone tower home was reviewed under these rules.
West of Interstate 5 as it ran on January 1, 1971, no building may exceed 30 feet, a limit only the voters can change. In the Coastal Overlay Zone a new home takes a Coastal Development Permit, and a house kept in part is measured by the 50 percent exterior wall rule.
The City adopted the state's 2025 fire hazard maps, effective August 30, 2025. In a Very High zone a new home is built to the ignition-resistant standards of the building code, and defensible space around it becomes part of the site plan.
Working with your architect, or ours
Bring an architect you already work with, or we introduce you to residential architects and engineers we have built with before. Either way BHI holds one contract and coordinates the drawings, the engineering, the permit and the build.
If you already have plans, we review them first for what it takes to build them on your lot.
From the lot to the house
A custom home starts as a graded pad, stakes and a drive. Drag across the picture to see the same hillside lot as a finished single-story house with its terrace, pool and motor court.
Process and responsibilities
The same six stages every BHI project moves through. A custom home leans hardest on the second: what the site and the rules allow, settled before any design is fixed. The process page lists the decisions that are yours, BHI's responsibilities and the outside consultants at each stage.
Scope and schedule
A custom home is shaped by its site before its finishes. These are the parts we work through with you before the design is fixed.
Local considerations
Nineteen offices issue permits in the county; pick yours below. The notes here are the City of San Diego's rules for new homes.
Our tools cover all 19 permit authorities: 18 cities and the County.
Any construction or demolition permit on a parcel with a structure 45 years old or older goes through the City's historical screening first (Municipal Code 143.0212). Interior work and permits limited to electrical, plumbing or mechanical work are exempt. A house that may be significant gets a site-specific study, and a designated site needs a Site Development Permit for a substantial alteration.
In the Coastal Overlay Zone, removing half or more of a house's exterior walls, measured in linear feet floor by floor, needs a Coastal Development Permit, including when it happens by accident. A replacement home that keeps part of the old house is measured the same way.
Between the ocean and Interstate 5 as it ran on January 1, 1971, no building or addition may exceed thirty feet. The City's voters set the limit in 1972, with four mapped exceptions.
A single-family lot in the City may be split once into two lots, neither under 1,200 square feet or under 40 percent of the original, with no more than four homes across both and no ADUs when the split and the new units are proposed together. The owner signs a three-year occupancy affidavit. A split in the Coastal Overlay Zone needs a Coastal Development Permit. Listed historic parcels are excluded, and so are Very High Fire Hazard zones unless the development complies with Chapter 7A of the building code.
The City adopted the state's 2025 fire hazard severity zone maps, effective August 30, 2025. In a Very High zone, new construction follows the ignition-resistant standards of the building code.
With a demolition permit for the old house, school fees are charged on the new home's assessable space, and the school district may credit the space that was demolished. On a partial demolition the fee falls on the net increase.
Planning aids
A first read of a lot, and the guides behind the rules above.
Real questions
Yes. A first read before you buy shows which authority reviews the lot, which overlays it sits in, what the zone allows, and what a survey, a soils report or a site visit would still have to settle.
It depends on where the lot is. The City of San Diego, one of the 17 other incorporated cities, or the County for unincorporated areas. Use the finder above to open the authority's own page, and confirm with that authority for your specific parcel.
Not before you call. Bring what you have, from a sketch to a full set. We work with architects you choose, or introduce you to residential architects and engineers we have built with before, and BHI coordinates them under one contract.
The City's environmentally sensitive lands rules apply. A steep hillside is a natural slope of 25 percent or more with at least 50 feet of rise, or 200 percent with 10 feet. If any part of the lot qualifies, the rules cover the whole premises and listed projects need a Neighborhood or Site Development Permit. Our three-story stone tower home in Black Mountain Ranch was reviewed under them.
Up to 30 feet, with a coastal permit. West of Interstate 5 as it ran on January 1, 1971, the Coastal Height Limit caps any building at 30 feet. In the Coastal Overlay Zone a new home takes a Coastal Development Permit, and a house kept in part is measured by the 50 percent exterior wall rule.
The materials and the space around the house. The City's 2025 fire maps took effect August 30, 2025. In a Very High zone the house follows the building code's ignition-resistant standards, from the roof and vents to the windows and siding, and defensible space is planned with the site.
The structure, the lot and the zone decide it. A remodel keeps what is sound; a replacement starts over under today's code. Before demolition a house 45 years old or older is screened for historic significance, and near the coast the 50 percent wall rule applies to a house kept in part. Our remodeling page covers the other path.
Longer than a remodel, and the site decides most of it. Due diligence and design come first, then plan check, then the build. A coastal lot, a hillside, or a parcel with a building 45 years old or older adds its own review before the permit. For our courtyard home in Black Mountain Ranch, the City issued the permit about four months after the application in 2008. Your own timeline is set with you once the project starts.
Often, under SB 9. In the City a single-family lot can be split once into two lots of roughly equal size, neither under 1,200 square feet or 40 percent of the original. The owner signs an affidavit of intent to live there for three years. Coastal lots need a coastal permit, and historic parcels and Very High fire zones are excluded unless the work complies with Chapter 7A.
They fall on the new space. With a demolition permit the fee is charged on the new home's assessable space, and the school district may credit the house that was demolished. Garages, patios and detached accessory structures aren't assessable space.
Yes, as one project. The house, a guest house, a pool house and the pool can be designed and permitted together. Our record includes a pool house with a bathroom in Black Mountain Ranch and 19 pool and spa permits. A guest house with its own kitchen is an ADU, with its own rules.
Book a call
Book 30 minutes with Koosha Tabrizi to talk through your lot and the house you have in mind.
BHI Builders (B H I Builders Inc.), California contractor license B #738313.
