Basement apartment with its own door at the foot of a side stair
Example project

- Home
- 1980s stucco house in Salt Lake City
- Original request
- A separate apartment downstairs for a parent, with a door of its own
- Space
- About 1,000 sq ft, reached from a door at the foot of the side stair
- Rooms
- A bedroom, a bathroom, a kitchenette and a living room
- Not included
- Electrical service upgrades and landscaping
- Cost
- $96,000
Scope of work
Framed and insulated walls, a fire-rated separating wall and floor against the house, interconnected smoke and carbon monoxide alarms, an escape opening for the bedroom, wiring and lights, a bathroom, a kitchenette with cabinets, counter and vent, flooring, paint, doors and trim. Utility upgrades and the stair itself are not part of this cost.
Project overview
In this example, the owners of a 1980s stucco house in Salt Lake City want their parent to live downstairs with a front door that is not the family’s. The house has a side stair, and a door at its foot opens into the lower level.
The plan gives the unit a bedroom, a bathroom, a small kitchen and a living room. Before any wall goes up, the owners check the city’s current rules for an accessory unit, and the plans show the escape opening, the alarms and the separation from the house.
The goal
The goal is a self-contained apartment with its own door and a legal way out of every sleeping room.
Process
- Before work The city’s ADU rules are read, the layout is drawn and the plans go to the permit office.
- Walls and systems Framing goes up with wiring, plumbing and ducts, and the inspector looks before anything is covered.
- Separation Board goes on the wall and ceiling shared with the house, and the inspector sees it before the joints are taped.
- Finish The unit is closed out with drywall, the kitchenette, the bathroom, flooring, paint and trim.
Planning right
- Read the city’s current ADU rules before the layout is drawn, because they can change.
- Ask the city what separate entry the unit needs.
- Make sure the furnace and water heater can be reached from the house side.
- Ask what the side stair and the door at its foot will need.



