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Wet crawl space and basements

To the home buyer or owner, it can be quite alarming to find water in the basement or crawlspace. Water under the home is most often an issue that can be corrected but It’s important to identify the source of the moisture and quickly. Here in North Carolina we get over 50 inches of rain annually. This adds to a lot of demand for the water resistance installation on the outside of the house, if any.

Here is a list of the most common ways that water can get into a crawlspace and basement. 

Gutter and Downspout issues

One of the most common sources of basement and crawlspace water is poor rainwater management. Debris from surrounding trees and vegetation can all easily overwhelm and clog gutters and downspouts, causing gutter to clog and overflow. Underground drainage piping can also become clogged or broken, leaving the downspouts to pour rainwater right next to the foundation. Or the gutters could be missing entirely. This still surprises me every time I see it.

Negative grade and poor drainage

The ground around the house should slope away and drain ground water away from the foundation. If this cannot be achieved naturally on the site and the house is located at a bottom of a hill, on the high ground side of the building the slope can be interrupted by a surface drainage system that diverts and disposes of rainwater runoff. Also, remember that mulch and rock does not count as grading.  Mulch is porous and water will drip right through it and onto the soil.  Check how deep the mulch surrounding the home is – be sure that the soil is what makes a positive slope, not the mulch.

Ground or subterranean water

In some instances, rainwater may saturate the soil around the home, especially in the wet months of the year or during a hurricane season.  When the soil becomes saturated, the water will find the path of least resistance, which could be the large pit in the ground that was dug for your crawlspace or basement.

Drain or Sump pump not functioning properly

Crawl spaces can often get neglected over long periods of time. Sometimes the home owners don’t realize the problem until they have had a home inspection, we hear this often. Sump pumps should be checked and serviced annually and before large storms to ensure they will operate as needed. Low point drains in the crawlspace should be kept clear and clean. Often we see them clogged with debris, or by plastic vapor barriers that prevent water from flowing to the drain

Leaking foundation wall

isn’t a guarantee. Foundations on older homes may be built of more porous materials such as terra cotta block, brick or CMU concrete block. These materials have more joints or are more porous and may allow more moisture into the home. A properly installed drain and trench system or sump pump can still keep moisture levels at an acceptable level.

Larger cracks sometimes develop in the foundation over time, as the foundation may have shifted or sinks. Especially around areas where rainwater and soil has exerted pressure. Downspout that has been draining near the foundation for a long time can wash away soil, which can lead to shifting in the foundation.  Cracks are an easy path for water to find.  Or even worse the soil under the foundation footing has shifted causing structural movement and problems.

Plumbing leaks

Sometimes the easiest source of water to find. When you find water in the crawlspace, always look above and around the standing water to see if there are any signs of a leak from a distribution or drain pipe. During our inspections we fill fixtures, sinks, tubs and run appliances to test the plumbing drain system looking for plumbing problems. Tub and shower drains or tiled showers are a common area where leaks can develop.

Basements and crawlspaces often go neglected, and some crawlspaces go unchecked for years, we recommend checking your crawlspace at least twice a year for leaks and other problems, the fall and spring are good times to check for unwanted standing water. We also recommend checking your sump-pump or low point drain to ensure its clear and will work when needed.  Standing water near the foundation and footings can lead to soil shifting or settling and can cause structural issues. As the old saying goes “An ounce of prevention is worth a pound of cure”.


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