Site Selection Shapes Every Design Decision That Follows
Site selection is one of the earliest and most consequential decisions in any project. A poorly chosen site can undermine the best building design, while a well-suited site can dramatically simplify design challenges and reduce project cost. The ARE PA division tests site selection knowledge because architects regularly advise owners on site criteria, conduct preliminary site feasibility studies, and must understand how site conditions drive design decisions. The exam presents site descriptions and asks candidates to evaluate their suitability or identify constraints.
Key Site Evaluation Criteria
Zoning and Land Use
Before any other analysis, the site must be verified to allow the intended use under local zoning. Zoning analysis includes: permitted uses, maximum floor area ratio (FAR), setbacks from property lines, height limits, parking requirements, and any overlay districts (historic, floodplain, transit-oriented). A site that is not zoned for the intended use requires a variance or rezoning, which adds time, cost, and uncertainty to the project.
Size and Shape
The site must be large enough to accommodate the building program plus parking, setbacks, and site amenities. The shape affects building organization: narrow sites constrain floor plate configurations; irregular sites create complex structural and organizational challenges. Access points from the street also depend on site shape and location relative to street intersections.
Topography
Sloped sites require grading, retaining walls, or stepped building design - all of which add cost. Steep slopes may also create drainage challenges and trigger erosion control requirements. However, topographic variation can also be an asset, allowing split-level parking under a building or creating dramatic landscape features. The key is understanding the site's slopes early and designing to work with the topography rather than against it.
Soil and Geotechnical Conditions
Poor soil conditions - expansive clays, fill material, high groundwater, contaminated soils - can dramatically affect foundation design and cost. A geotechnical investigation (boring logs and soil testing) should be commissioned early to inform foundation decisions. Sites with poor bearing capacity require deep foundations, which can be expensive. Contaminated sites require remediation before development can proceed.
Utilities
The availability and capacity of utilities - water, sewer, gas, electric, telecommunications - must be verified for the site. Remote sites may require expensive utility extensions. Sewer capacity may be limited, requiring the owner to pay for capacity upgrades. Electrical service capacity should be confirmed with the utility before finalizing an equipment-intensive building program.
Access and Transportation
Vehicle access, pedestrian connectivity, and transit proximity all affect site suitability. Traffic impact studies may be required for high-traffic uses. Curb cuts and access drives must be coordinated with transportation authorities. Pedestrian access from transit to the building entrance is a LEED and FHA consideration.
Environmental Factors
- Floodplain: FEMA flood maps identify areas subject to 1% annual chance flooding (100-year flood). Development in floodplains requires compliance with FEMA floodplain management regulations.
- Wetlands: Jurisdictional wetlands may not be filled without Army Corps of Engineers permits.
- Existing vegetation: Protected trees, mature canopy, and habitat areas may restrict building placement.
- Solar access: Adjacent buildings or trees may shade the site, affecting passive solar design or PV panel placement.
Key Exam Points
- Zoning verification comes first - confirms the intended use is permitted.
- Geotechnical investigation is owner's responsibility (AIA B101 Article 5).
- Floodplain sites require FEMA FIRM map analysis and may require elevation above BFE.
- Utility availability and capacity must be verified early - extensions are expensive.
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