What To Look For Inside - Basement and Crawlspace Flashcards
Basement and Crawlspace
The home inspector should look at all readily accessible surfaces in the house and report upon observed indications othe following:
water stains or marks;
signs of water intrusion;
standing water;
efflorescence;
cracks;
walls that are out of plumb;
piers and columns that are out of plumb;
sagging floor joists;
band joist rot;
sill plate rot;
untreated wood in direct contact with concrete (but note that some codes permit untreated wood to contact interior piers filled with concrete);
evidence of animals;
mold or fungus;
crumbling mortar joints;
repairs;
sealers;
paint;
dehumidifiers;
rust at the bottom of the heating system;
crawlspace ventilation;
evidence of wood-destroying organisms;
wood-destroying organism treatment holes;
daylight through the foundation;
insulation vapor-barrier orientation;
waterproofing systems;
standing water in the sump pit;
exposed dirt floor in the crawlspace;
additional jack or pier supports;
cold joints in poured concrete walls;
rusted steel columns;
missing column-to-beam connections; and
poor ventilation.
Concrete Walls and Floors
Key Points:
Cracks in Concrete:
Cracks 1/4 inch wide or more may indicate serious issues; recommend evaluation by a licensed engineer.
Inspectors should observe and report, not analyze.
Types of Cracks:
Diagonal cracks wider at the bottom suggest settlement.
Diagonal cracks over windows may indicate a weak header.
Horizontal cracks near the frost line often result from frost damage.
Hairline cracks (uniform or caused by shrinkage) are usually not structural but may allow water intrusion.
Anchor Bolts for Sill Plates:
Use 2-inch washers.
Keep bolts:
At least 7 bolt-diameters from the end of the sill.
No more than 12 inches from the end.
Install at least two bolts per sill piece.
Heating System Check:
Look for rust at the base. Rust may indicate past flooding, water intrusion, or standing water.
Foundation and Soil Forces
Key Points:
Unheated Homes and Frost Depth:
Without heat, the frost depth increases, causing potential heaving of the foundation.
Soil Forces on Foundations:
Dry Soil: Can exert pressure, leading to cracks.
Wet Soil: Creates hydrostatic pressure, greater than dry soil, which can crack foundations and lead to water intrusion.
Frozen Soil: Expands as water freezes, exerting even greater pressure than wet soil, potentially cracking the foundation.
Signs of Moisture Intrusion:
Inspect for watermarks (wet, damp, or dry) near cracks or below them, indicating past or active water intrusion problems.
Regional and Weather Factors:
Soil forces depend on location, climate zones, and weather conditions.
Home inspectors evaluate based on current conditions only; future weather events or changes are not their responsibility.
Water’s Impact on Structures:
Water destroys porous building materials, leading to structural deterioration.
Inspect and report any visible water intrusion marks on accessible surfaces, as per InterNACHI Standards of Practice (nachi.org/sop).
Key Points: Moisture, Foundations, and Crawlspaces.
What is capillary action, and how does it affect buildings?
Capillary action is the ability of liquids to flow in narrow spaces against gravity. It can draw moisture into building materials, leading to potential damage.
Soil and Water Forces on Foundations
What is impervious soil, and how does it affect foundations?
Impervious soil is soil that does not let water pass through easily, like clay or compacted soil. It can cause drainage problems, water pooling, or hydrostatic pressure against foundations, leading to potential structural issues.
Impervious soil can redirect water toward foundations, causing moisture intrusion and cracking.
What is hydrostatic pressure, and why is it significant?
Hydrostatic pressure is the force of water pushing against foundations (e.g., walls, slabs). It can cause cracks and water intrusion due to water’s high weight (60 lbs per cubic foot).
What should be inspected for water issues near foundations?
Check grading, downspouts, low areas, water puddles, gardens near walls, and moisture indications in basements or crawlspaces.
What are the minimum access requirements for crawlspaces?
Access opening: 18x24 inches.
Clearance:
18 inches below joists.
12 inches below beams (or 24 inches in some codes).
What are the ventilation requirements for crawlspaces?
One vent within 3 feet of each corner.
Minimum net ventilation: 1 sq. ft. per 150 sq. ft. of crawlspace (less with a vapor barrier).
What is the difference between conditioned and vented crawlspaces?
Conditioned crawlspaces: Insulated, drier, and better for humid climates.
Vented crawlspaces: Allow outside air, which can cause condensation and mold in humid regions.
What safety precautions should be taken when inspecting crawlspaces?
Watch for animals (e.g., snakes, rats), water, and exposed wiring.
Avoid entering wet crawlspaces or unstable ground.
What causes shrinkage cracks in foundations?
Shrinkage cracks occur during the curing of poured concrete. They are usually hairline and not structural concerns but may allow water intrusion.
What is the danger of water near a foundation?
Water can destroy porous materials and cause structural damage. Wet soil can lead to cracks and water intrusion.
How can a home inspector identify water-related problems in crawlspaces?
Inspect for grading issues, downspout performance, water puddles, low areas, moisture intrusion, and damage near gardens or planters.
What are the benefits of conditioned crawlspaces?
Reduced condensation and mold in humid climates.
Better energy efficiency and comfort.
Safer and more durable compared to vented crawlspaces.
What precautions should be taken with crawlspace ventilation in humid climates?
Unvented, conditioned crawlspaces are better, as outside humid air can lead to condensation and mold.
