Site Analysis on the ARE
Site analysis is a core skill tested in the Programming & Analysis (PA) and PPD divisions. The ARE evaluates your ability to read site conditions, identify constraints and opportunities, and translate them into appropriate design responses.
Topography and Grading
Topographic contour maps reveal slope, drainage patterns, and buildable areas. Key concepts include:
- Contour intervals: Closely spaced contours indicate steep slopes; widely spaced contours indicate gentle grades.
- Slope calculation: Rise ÷ run, expressed as a percentage or ratio. Slopes exceeding 10% present challenges for building placement, accessibility, and erosion.
- Cut and fill: Earthwork balanced to minimize hauling costs and site disturbance; the balance point (where cut equals fill) is the most economical grading strategy.
- Contour manipulation: Contours point uphill through valleys and downhill across ridges; water flows perpendicular to contours.
Climate Analysis
Climate data drives passive design strategies, building orientation, and system selection:
- Temperature ranges: Determine heating/cooling demand and the value of thermal mass.
- Prevailing winds: Inform natural ventilation strategies (summer breezes) and windbreak placement (winter winds).
- Precipitation: Affects drainage design, waterproofing requirements, and landscape selection.
- Humidity: Drives vapor control strategies and the selection of passive vs. active dehumidification.
Solar Orientation
Solar orientation affects energy performance, daylighting, and thermal comfort:
- South-facing facades (northern hemisphere) receive the most predictable solar exposure and are easiest to shade with horizontal overhangs.
- East and west facades receive low-angle sun that is difficult to shade, contributing to overheating and glare.
- North-facing facades receive minimal direct solar gain, making them ideal for diffuse daylighting (studios, galleries) and reducing cooling loads.
- Building elongation along the east-west axis maximizes south-facing exposure and minimizes problematic east-west exposure.
Views and Context
Site analysis considers visual access to desirable features (water, mountains, urban landmarks) and screening from undesirable views (highways, service areas). Adjacent building heights, setback patterns, and neighborhood character inform massing and facade design, particularly in historic or design-review contexts.
Drainage and Hydrology
Natural drainage patterns, watershed boundaries, floodplain delineation (100-year and 500-year), and soil permeability all constrain building placement and inform stormwater strategy. Grading must direct water away from building foundations, with a minimum 5% slope for the first 10 feet. See Stormwater Management for detailed runoff calculations and BMPs.
Soils and Vegetation
Soil bearing capacity determines foundation type, while soil permeability affects drainage and stormwater infiltration. Existing vegetation - especially significant trees - may be protected by ordinance and should be incorporated into site design where possible. Soil types (clay, sand, silt, organic) each have distinct structural and drainage characteristics.
Utilities and Access
Utility availability (water, sewer, electric, gas, telecommunications), capacity, and connection points shape site layout. Vehicular access, pedestrian circulation, and service/emergency vehicle access must comply with local regulations and zoning requirements.
Site analysis informs Environmental Systems strategies and Sustainable Design decisions. Practice site analysis scenarios with PA mini exams. Sign up free for complete site analysis practice content.