Igni

Permit & ADU glossary

Plain-English definitions of the permit, ADU and California-housing terms that show up across Igni — each one links out to the long-form guides and articles.

Accessory Dwelling UnitAn accessory dwelling unit (ADU) is a smaller, self-contained second home on the same lot as a primary residence.Building PermitA building permit is official authorization from a local building department to perform construction, ensuring it meets code.By-Right / Ministerial ApprovalBy-right or ministerial approval grants a permit against objective standards without discretionary review or public hearings.California SB-10California SB-10 is an optional tool letting cities voluntarily upzone parcels up to ten units in transit-rich or urban areas.California SB-9California SB-9 is a ministerial, by-right path letting qualifying single-family lots be split and host up to two units per lot.Certificate of OccupancyA certificate of occupancy is a document issued after final inspection confirming a building is safe and legal to occupy.Detached vs Attached ADUDetached vs attached ADU: a detached ADU is a standalone structure, while an attached ADU shares at least one wall with the main home.JADU vs ADUJADU vs ADU: a JADU is a small unit built inside an existing home's walls, while an ADU can be a larger attached or detached unit.Junior ADU (JADU)A junior ADU (JADU) is a small unit, typically up to 500 sq ft, created within the existing walls of a single-family home.Lot Split (Urban Lot Split)An urban lot split is the SB-9 mechanism to divide one qualifying single-family lot into two, each able to hold housing.Missing Middle HousingMissing middle housing is house-scale buildings with multiple units — duplexes, triplexes, fourplexes, and townhouses.Permit ValuationPermit valuation is the declared or estimated construction cost of permitted work, used to calculate fees and as a data signal.

Informational only, not legal advice. Housing and permitting rules change and vary by jurisdiction — verify current requirements before relying on anything here.