Knoxville Home Inspection: Foundation Terms Explained

Foundation and crawl space notes are common in East Tennessee home inspections, where many homes sit on crawl spaces or basements built into slopes. Here's what the usual terms mean. Your inspector saw the house and is the best guide to your report; a foundation contractor or engineer can follow up on anything serious.

Cracks and movement

Shrinkage crack — A thin, usually vertical crack in poured concrete from curing. Common and often cosmetic.

Stair-step crack — A zigzag crack along mortar joints in block or brick, often from settlement. See wall and crack repair.

Horizontal crack / bowing — Soil pressure pushing a block wall inward. Worth a prompt professional look.

Differential settlement — One part of the house has settled more than another, often shown by sloping floors and sticking doors.

Water

Efflorescence — White, powdery deposits on masonry where water has moved through and evaporated.

Evidence of moisture intrusion — Stains, rust or damp spots showing water has entered a basement or crawl space.

Negative grading — Soil sloping toward the house, sending water to the foundation. See drainage and grading.

Sump pump present / not tested — A pump to remove water; ask whether it works and has a backup.

Crawl spaces

Missing or damaged vapor barrier — The plastic over the soil is torn, missing or incomplete, letting ground moisture into the air. See crawl space moisture.

Sill plate / joist rot — Decay in the wood framing above the foundation, usually from long-term moisture.

Inadequate support / shimmed piers — Posts or piers that are undersized, loose or stacked with shims. See crawl space repair.

How serious is it?

• Monitor: hairline shrinkage cracks, minor efflorescence, small grading issues.
• Fix soon: damp crawl spaces, missing vapor barrier, downspouts draining at the wall.
• Before closing: bowing walls, active water entry, rotted framing, widening cracks.

For inspectors and agents

You're welcome to link this page for clients. Related: signs of foundation problems · limestone and sinkholes · foundation inspections