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CREIA Stresses the Importance of Good Drainage Around Your Home

June 2003 — The California Real Estate Inspection Association (CREIA) reports that moisture intrusion damage and plumbing leaks are the largest repair expense most homeowners face today. Deferring maintenance for any moisture problem is not wise. Plumbing and drainage problems can escalate to health issues as molds can grow on virtually any substance when moisture is present.

Make sure your home’s roof, grade-level, and underground drainage systems are designed to redirect water flow away from the perimeter foundation. Properly installed drainage systems help prevent flooding, soils erosion, excessive moisture conditions, foundation settlement, and moisture infiltration into below grade rooms and storage areas. Typically, these drainage systems are referred to as a “French drain.” A French drain consists of trenches that are lined with drainage cloth, filled with rock, and contain perforated piping with the holes at the four and eight o’clock position. Ground water favors French drains because they provide an easier flow path than the natural grade of the property. Simply stated, a French drain creates a more permeable route for flow and carries the water to a safe disposal point.

The migration of moisture against either a home’s perimeter concrete foundation stem wall or beneath a concrete slab type foundation can be costly for homeowners because of the potential damage possible to a home’s support systems, as well as to personal contents and mechanical systems, along with the possible encouragement of mold and pest infestation.

To ensure that a home’s drainage system is adequate in design and effective during wet weather, make sure it is evaluated by a qualified and experienced inspector. If a problem is discovered by a professional home inspector, a geotechnical expert may be further recommended to perform a site evaluation and provide specifications and a cost analysis for the proper drainage system.

If any flooding has recently occurred, the foundations, subfloor framing, and other building components should be carefully examined for possible moisture-related damage. Your inspector has a professional obligation to inspect the crawlspace beneath the dwelling, unless that portion of the home is inaccessible. In that case, lack of access should be specifically noted in the inspection report, with a recommendation for further evaluation as soon as access can be provided. The California Real Estate Inspection Association (CREIA) includes the inspection of the crawlspace as part of their Standards of Practice for all member inspectors.