Can I add ADUs to my existing LA apartment building — and is it worth it?
Yes. State law requires cities to allow ADUs on multifamily lots two ways: converting non-livable space inside the existing building — garages, storage rooms, boiler rooms — into up to 25% of the existing unit count (minimum one), plus detached ADUs in the yard, which SB 1211 (2025) expanded to as many as eight, capped at the number of existing units. Approval is ministerial, no replacement parking can be required for converted stalls, and each finished unit is new income on land you already own — typically the cheapest unit an LA owner can create.
The math that makes conversions pencil.
A tuck-under garage bay converted to a studio might cost $100,000–$200,000 all-in depending on utilities, structure, and finish — against $2,000+ per month of market rent in most LA submarkets. That is a return on cost far above what buying units at today's cap rates delivers, which is why buyers now underwrite convertible space as latent income. An eight-unit building with six garages can plausibly become a ten-unit building without touching the existing tenants. The constraints are physical and practical: utility capacity, ceiling heights, egress, and whether tenants currently rent those garages (parking is a service that has its own rules when reduced on RSO tenancies). Feasibility is a contractor-and-architect question; the value question is mine.
How new ADUs interact with RSO.
The regulatory posture of a new ADU differs from the building it joins. A newly constructed ADU has a post-1978 certificate of occupancy, so it is generally not subject to RSO's rent cap — though it is covered by the citywide just-cause ordinance, and AB 1482's cap catches it once the 15-year window passes. Confirm the specific unit's status with LAHD, because converted space inside an RSO building can be treated differently than new detached construction. Two cautions: never convert space a sitting tenant has the right to use without proper process, and never skip permits — unpermitted units are a discount at sale, while permitted ADUs are appraisable income. The paperwork is the difference between value added and liability added.
Do I lose required parking when I convert garages to ADUs?
State ADU law bars cities from requiring replacement of parking demolished or converted for an ADU, and AB 2097 separately eliminates minimums near major transit. The market question — whether your tenants need those stalls — still deserves an honest answer.
How many ADUs can a 12-unit building add in total?
Up to 3 conversion ADUs inside existing non-livable space (25% of 12), plus up to 8 detached ADUs under SB 1211 — subject to lot size, setbacks, and building code. Most owners phase in far fewer; the law is rarely the binding constraint.
Do ADUs raise the building's appraised value?
Permitted, rented ADUs add income that income-approach appraisals and buyers capitalize — though lenders vary in how they credit ADU rent. Unpermitted conversions do the opposite: they add risk that gets priced against you.
SHAYA LOWENSTEIN · LYON STAHL INVESTMENT REAL ESTATE · DRE #01942326 · (323) 944-2221