New Construction
ADU
Hillside Build

West Hills ADU

Aforma supported the design and documentation of a new accessory dwelling unit (ADU) on a sloped West Hills site. The project focused on optimizing allowable building coverage, coordinating structural requirements, and delivering clear, build-ready documentation within strict zoning and site constraints.
Overview

Building Within Tight Site and Zoning Constraints

This project involved the design and documentation of a new ADU on a constrained hillside property. Existing conditions included a primary residence with limited available footprint, requiring careful planning to stay within zoning limits while maximizing usable space.

The proposed structure introduces a 900 SF footprint while maintaining compliance with lot coverage, impervious surface limits, and setback requirements. The design balances efficiency, structural feasibility, and site integration.

Location:
Portland, OR
Year:
2023
Status:
Completed
Collaborators
Architect, Structural Engineer
Project Type:
Accessory Dwelling Unit (ADU)
Challenge

Navigating Coverage Limits and Sloped Site Conditions

The project required strict adherence to zoning regulations, including maximum building coverage and setback requirements, while working within a sloped terrain.

  • Limited allowable building footprint relative to lot size
  • Coordination of impervious surface calculations
  • Structural considerations due to hillside conditions
  • Compliance with height and setback restrictions
Approach

Coordinating Site Data, Zoning, and Buildability

Aforma developed coordinated drawings and models to validate design decisions early and ensure compliance before construction.

  • Verified building coverage against allowable zoning limits
  • Coordinated site layout, driveway, and access conditions
  • Integrated structural considerations for elevated construction
  • Produced clear documentation for permitting and contractor use
Result

Delivering a Compliant and Buildable ADU Design

The project achieved a fully coordinated design that maximizes allowable space while maintaining compliance with all site and zoning requirements.

All major constraints were resolved during the design phase, reducing risk during permitting and construction.

Optimized Building Coverage
Maximized usable footprint within strict zoning limits
Code-Compliant Design
All setbacks, height, and coverage requirements met
Reduced Construction Risk
Early coordination minimized on-site conflicts
Efficient Site Utilization
Integrated driveway, access, and structural conditions into a cohesive plan