Building an ADU in National City
National City's housing stock is older than most of the county. Expect to find galvanized water lines, cast iron drains, original electrical panels and garages built without proper footings. None of that rules out an ADU, but it shapes the scope and the budget.
Lots are often narrow, so side-yard access for materials and equipment matters. Alley access makes construction easier and can provide the ADU's own entry.
Permits go through National City's Building and Planning divisions. If the garage or any rear structure was built or altered without permits, plan to legalize or replace it as part of the project.
What state law allows
State ADU law works in favor of National City's small, older lots. One ADU plus one junior ADU is allowed on most single-family lots, and the city has 60 days to review a complete application that meets the rules.
- Converting a garage to an ADU generally does not require you to replace the lost parking spaces.
- Owner-occupancy is no longer required for a standard ADU. A junior ADU still requires the owner to live on the property.
- ADUs under 750 square feet are exempt from impact fees, and units of 500 square feet or less are generally exempt from school fees.
- Detached ADUs typically need only 4-foot side and rear setbacks.
Convert the old garage or replace it?
A detached garage at the back of a National City lot is the natural candidate. A conversion reuses the walls, roof and slab, so it is usually the faster and lower-cost route.
Many of these garages are old enough that the slab has no footings and the framing has seen better days. When that is the case, taking the garage down and building a new detached ADU in its place can cost close to the same and leaves you with a sound building on a proper foundation.
How an All Pro Contractor ADU project runs
- Site visit to review the garage or yard, access, utilities and the goals for the unit.
- Written estimate covering the scope discussed, with design, engineering and permit responsibilities spelled out.
- Plans and permit submittal, either through our design partners or with plans you already have.
- Construction: foundation or slab work, framing, utilities, insulation, drywall, finishes and final inspection.