Elkwood Street Two-Story ADU + SB9

Designed by 121 Design Build, this Winnetka project adds two stacked 804-square-foot dwellings behind an unchanged 1,155-square-foot single-family home. The first floor contains a two-bedroom, two-bathroom SB9 residence, while the second floor provides a separate two-bedroom, two-bathroom ADU. Each unit includes its own kitchen, living room, closets, and laundry facilities. The new Type VB building is planned at two stories with a maximum proposed height of 21 feet.

Two new dwellings: One SB9 unit and one ADU expand the property to three total residences.

First-floor SB9 unit: 804 square feet with two bedrooms and two bathrooms.

Second-floor ADU: 804 square feet with two bedrooms and two bathrooms.

Complete amenities: Each new residence includes a kitchen, living room, closets, and laundry.

Existing home retained: The 1,155-square-foot, three-bedroom SFD remains unchanged.

Independent access: Exterior stairs provide direct access to the upper-level residence.

Fire protection: The new building is designed for a fully sprinklered NFPA 13D system.

Rated assemblies: One-hour wall and floor-ceiling construction separates the dwellings.

Acoustic separation: Assemblies target 50 STC and 50 IIC performance between units.

Durable exterior: Fire-rated stucco walls are paired with warm wood-look accents in the renderings.

Class A roof: A low-slope roof is specified with gutters and downspouts.

Solar readiness: Plans designate a 300-square-foot PV-ready roof area.