National Home Inspector Exam

Site conditions encompass everything outside the building envelope that affects the structure's integrity, safety, and habitability. Understanding site conditions helps inspectors identify drainage problems, safety hazards, and conditions that may lead to structural damage.

Proper grading directs surface water away from the foundation. The standard recommendation is a minimum slope of six inches within the first ten feet from the foundation wall. Negative grading, where soil slopes toward the foundation, creates conditions for water infiltration, foundation damage, and basement moisture problems.

Inspectors must evaluate the overall lot drainage pattern. Water should flow away from the structure toward appropriate discharge points such as streets, swales, or storm drains. Ponding water near foundations indicates inadequate grading or drainage system failure.

Surface drainage systems include swales, which are shallow channels that direct water flow, and French drains, which are gravel-filled trenches containing perforated pipes that collect and redirect subsurface water. Catch basins collect surface water and channel it to underground drainage systems.

Retaining walls hold back soil and prevent erosion on sloped lots. Common materials include concrete block, poured concrete, timber, stone, and segmental retaining wall units. Inspectors evaluate retaining walls for signs of failure including leaning, bowing, cracking, and displacement.

Proper retaining wall construction includes adequate drainage behind the wall, typically through weep holes or drainage aggregate with perforated pipe. Hydrostatic pressure from trapped water behind retaining walls is the primary cause of failure. Walls over four feet typically require engineering design and may need tiebacks or deadmen anchors.

Concrete driveways and walkways should slope away from structures. Inspectors evaluate these surfaces for cracking, settlement, heaving, and trip hazards. Cracks wider than one-quarter inch or vertical displacement greater than one-half inch warrant reporting.

Asphalt driveways deteriorate through oxidation, causing brittleness and cracking. Alligator cracking indicates base failure requiring complete replacement rather than surface repair. Proper asphalt installation includes adequate base preparation and edge support.

Trees and shrubs affect structures in multiple ways. Root systems can damage foundations, driveways, walkways, and underground utilities. The general guideline is that tree roots extend one to three times beyond the drip line. Large trees within ten feet of foundations warrant mention.

Vegetation in contact with structures promotes moisture retention and pest entry. Vines can damage siding and mortar. Overhanging branches can damage roofing and deposit debris. Inspectors recommend maintaining clearance between vegetation and structures.

Fences define property boundaries and provide security and privacy. Inspectors evaluate fence condition including posts, rails, and infill material. Leaning posts indicate inadequate footings or rot. Gate hardware should function properly for security purposes.

Swimming pool fencing has specific safety requirements. Most jurisdictions require self-closing, self-latching gates with latches positioned on the pool side at least 54 inches above grade. Pool barriers typically must be at least 48 inches high with no footholds that allow climbing.

Hillside lots present unique challenges. Inspectors evaluate the potential for soil movement, erosion, and drainage problems. Signs of soil movement include cracked flatwork, leaning structures, diagonal cracks in foundations, and doors or windows that stick.

Cut and fill slopes require evaluation. Cut slopes expose natural soil and are generally more stable. Fill slopes contain placed soil that may settle over time. Improperly compacted fill can lead to significant settlement issues.

Inspectors should recognize potential environmental hazards visible during inspection. These include abandoned underground storage tanks evidenced by fill pipes or vent pipes, potential contamination from nearby commercial or industrial properties, and evidence of previous flooding.

While environmental testing exceeds the scope of standard home inspections, inspectors should recommend environmental assessments when visual evidence suggests potential problems.