Concerns of a leaking basement
Since most basements are below grade and surrounded by soil they are at a high risk of leaking. A wet basement can lead to problems such as damage to the foundation, toxic mold growth, building rot, termite damage and peeling paint. The quality of the indoor air can also be affected by a wet basement. As a homeowner you’ll want to be aware of the things you can do to help keep your basement or crawl space dry and prevent damage. Checking for water seepage in the basement is an important aspect of a home inspection.
Divert water away from the foundation
The importance of the gutter system cannot be overstated. There is a tremendous amount of water shed by the roof in even a short rainfall. The water needs to be diverted away from the foundation. The downspouts should be extended at least 5 feet away from the house. Gutters need to be maintained so rainwater and snow melt flow freely.
The finish grade around the house should slope away from the house for at least 10 feet. If there are low spots where water pools near the foundation they should be filled in and evened out. If you have a condition where one or more sides of your house face an upward slope then a swale can be used to divert the water. A swale is a shallow ditch. A swale should slope away from your house for 10 to 15 feet. It should then empty into another swale which directs water around the foundation to the downhill side of the house.
Repair cracks and holes in foundation
Here are some steps to take if you suspect that water is entering the basement through cracks or holes:
Find the areas where water may be entering through cracks or holes by checking for moisture, leaking or discoloration. The entire basement should be examined. Especially in cases where leaking or flooding has not been obvious, but moisture buildup is readily apparent.
A mixture of epoxy and latex cement should be used to fill small hairline cracks and holes. This is a waterproof formula that can help ensure that moisture and water do not penetrate basement walls. It is effective mainly for very small cracks and holes.
Any cracks larger than about 1/8-inch should be filled with mortar made from one part cement and two parts fine sand, with just enough water to make a fairly stiff mortar. It should be pressed firmly into all parts of the larger cracks and holes to be sure that no air bubbles or pockets remain. As long as water is not being forced through basement walls due to outside pressure, the application of mortar with a standard trowel will be sufficient if special care is taken to fill all cracks completely.
If water is being forced through by outside pressure, a slightly different method of patching with mortar can be used. Surface areas of walls or floors with cracks should first be chiseled out a bit at the mouth of the crack and all along its length. Using a chipping chisel and hammer or a cold chisel, cut a dovetail groove along the mouth of each crack to be filled, and then apply the mortar thoroughly. The dovetail groove, once filled, should be strong enough to resist the force of pressure that was pushing water through the crack.
If you have water seepage in your basement but do not want to tackle the job yourself then contact a reputable foundation or waterproofing contractor. Over time a leaking basement can cause costly structural damage and unhealthy living conditions. Diverting water away from your home is the key to preventing wet basements.
As a home inspector, checking for conditions that may lead to water intrusion is a critical aspect of the home inspection process.