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Matthew Steger WIN Elizabethtown

Preventing A Wet Basement

The most common complaint amongst home buyers, based upon insurance claims, pertains to wet basements. In many cases, paying a basement water-proofing company $5,000 - $20,000 to “water-proof” your basement is a waste of money as there are simple inexpensive things that nearly every home owner can do to prevent a wet basement.

A wet basement is generally caused by how water (rain and snow melt) is handled around the home’s exterior. Getting water away from your home as quickly as possible is key. Improper grade, clogged gutters/downspouts, downspouts and sump pumps discharging along the home’s foundation, and failed sump pumps are the most common culprits. In some cases, a high water table is the reason, and in this case, having a professional water-proofing company install a perimeter drain system with one or more pumps is likely the only possible repair method. In the other cases, though, home owners can easily and inexpensively prevent a wet basement.

The grading around the home’s perimeter should be somewhat compacted and pitch away from the foundation. Doing this encourages water to run away from the home’s immediate perimeter simply by gravity. If the soil is not compacted, the water will seep through it and drain along the foundation walls. Regrading is fairly straightforward and entails adding backfilled dirt, compacting it, and then ensuring the pitch continues at least 4’ away from the foundation. If there is a hill near the home that may encourage runoff to flow towards the home, adding an in-ground drain system or swale may be warranted.

Gutters and downspouts that are full of leaves and debris can’t properly drain. Instead, the gutter will likely overflow thus draining water along the foundation below the gutter. In some cases, the weight of the water and debris can cause a gutter to sag and sometimes even fall off the home. A gutter covering of some sort is likely needed if there are deciduous trees near the home. In the fall when the leaves fall and blow around, at least some will very likely find their way into your gutters.  There are various gutter cover products on the market; some are very good and some fall out easily and work poorly. Even with a gutter covering installed, they should still be checked on a regular basis in case leaves partially block the gutter covering itself.

The gutter below is full of water and the weight of the water is causing the gutter to sag. Over time, the gutter can literally fall off the building. You can also see that the gutter’s downspout discharges along the building. 

Improper downspout and sump pump discharge is the most common cause of wet basements. The amount of water that a gutter and downspout drains is large since this water is roof runoff. The larger the roof, the much higher volume of water to discharge. All of that water running into a few downspouts then discharges along the foundation; it is safe to say that at least some of this water will likely find its way into the basement. A sump pump that discharges water right outside the home will likely keep emptying the same water over and over out of the sump pit. The reason is, since the water gets drained along the exterior foundation, it often then seeps down into the soil right outside the home finding its way right back into the sump pit. I always recommend extending sump pump drain pipes and downspouts at least 4’ from the home, although further is even better. Solid (non-perforated) drain pipe is readily available at any hardware store and can easily be added to extend a sump pump drain or downspout away from the home.

This downspout discharges an insufficient distance from this home’s foundation. It is no wonder why this basement corner had water stains.

 A failed sump pump will likely lead to the basement flooding since it can’t drain a sump pit full of water. The first heavy rain will allow the sump pit to overflow and flood the basement. Periodically manually checking your sump pump monthly by either pouring water into the sump pit or manually lifting the float switch (assuming there is some water in the sump pit) will ensure that the pump is ready to roll. If the pump fails, though, of course, basement flooding will likely occur. That is why I also recommend to my clients to consider adding a battery-powered backup pump.  A backup pump sits above the primary (120 Volt house-powered) pump and will kick in if the primary pump does not turn on, because of as either a faulty pump or a power failure. The backup pumps have a battery that gets regularly trickle charged over time and can save the day.  A backup pump is a must if the basement is used for storage and even more, if the basement is finished. A $350 backup pump system can prevent $50,000+ in damage to a flooded finished basement.

If the basement windows or crawl space vents terminate at or below grade (such as in the photo below), this likely will also lead to water entering the basement or crawl space during a heavy rain. Window wells should be installed to help channel ground water away from the basement windows or crawl space vents.

In some cases, the water table may be high around the home. This is often caused by either the geography of the area, such as a creek right along the home, or the type and condition of the soil under the home. When it rains, the soil immediately next to the home gets saturated quickly and can’t properly drain away. I’ve actually inspected homes over the years that either had a spring in the basement or a creek literally running through the basement. In these cases, multiple industrial-rated pumps are needed. Installing an average sump pump won’t likely be able to handle the issue since these aren’t rated for full duty cycle. In other words, these pumps are meant for occasional use, whereas a higher rated full duty cycle pump is designed to run much more often and will last longer due to this regular usage.

Most modern homes are built with a weep tile drain system installed around the outside of the foundation’s footer. This pipe is designed to catch ground water before it can get into the basement; the pipes then normally run into the basement below the floor and discharge into one or more sump pits. As noted above, a properly functioning pump is then needed to discharge this water to grade from the home. Many city and township ordinances forbid discharging sump pumps into the public sewer system. Sometimes, the weep tile drain pipe can get blocked with stone or mud. In this case, the system won’t properly drain. This can allow for a wet basement. A lot of times, though, it takes some investigative work by a qualified contractor to diagnose the problem (since the cause is underground) and correct it. If the exterior weep tile pipe needs to be accessed or replaced, this is a large cost repair due to the excavating costs and labor.

Foundation type can also play a role in how dry a basement may be. Most home foundations are constructed of concrete block. This material is not very water resistant and can readily allow for water to pass through it. This is why it is important to follow the above suggestions as a concrete block foundation can stay dry by doing simple things. Most concrete block foundations will show minor moisture entry over time. It can be minor water stains or white-colored efflorescence. Efflorescence is a salty residue left on the block due to the block’s lime content. As moisture passes through the wall, it brings some lime with it. The moisture evaporates, but the lime remains. It seems to be quite rare, based upon my experience inspecting homes, to have a 20 year old concrete block foundation without at least a small amount of efflorescence on it.

Many modern homes, however, have poured concrete foundations. Due to their solid concrete nature, these foundations are generally better at preventing water penetration. Poured foundations are costlier than block but can be assembled quicker and are stronger than block and, of course, tend to be more impervious to water penetration compared to block.

As an agent or home buyer, there are some simple things to look for when checking to see if a basement may have taken on water in the past. Of course, you may see considerable water stains on the foundation walls and basement floor. Look at objects that are original to the home such as the bottom of the support posts and the basement staircase. Water and/or rust stains at these areas is a clue. In some cases, however, the stains may be related to a prior leaky water heater, for example. Of course, if everything in the basement is lifted off the floor on high shelves or pallets, that may also be a clue of past water accumulation issues.

In all cases, question the home’s seller and make sure that any and all prior water accumulation issues during their ownership (whether it is minor water entry, basement flooding, or a plumbing leak or a water heater failure) is fully documented on the required PA property disclosure statement. If there have been prior issues, ask for documentation about when, how often, and how the issue occurred, whether repairs were made, and ask for copies of any warranties related to any professional repairs or modifications.

In all basements, I also recommend running a dehumidifier from approximately May to October to help control regular humidity. Of course, a dehumidifier won’t prevent water entry into the basement, but can help prevent musty odors, minor mold, and increase interior comfort and will also help lighten the load on your central A/C system. A/C systems spend a good amount of effort to dehumidify your home while cooling it.

Also, home buyers should seriously consider having their home inspector perform an infrared (IR) thermography scan of their finished basement (assuming their inspector offers this service and is a certified infrared thermographer). An infrared thermography scan may show hidden water behind fixed wall/ceiling/floor coverings that may otherwise go unnoticed by a home inspection alone.

The below photo was taken at a recent inspection. According to the seller's disclosure, the seller bought the property in 2000 and declared 'no water in the basement during their occupancy', yet we saw this information written near the top of the basement steps (about 12" below the level of the main floor). You can also see a faint water stain in this area, too.

 © 2018 Matthew Steger


Matthew Steger, owner/inspector of WIN Home Inspection, is a Certified Level 1 Infrared Thermographer, an engineer, and an ASHI Certified Inspector (ACI). He can be reached at: 717-361-9467 or msteger@wini.com.

WIN Home Inspection provides a wide array of home inspection services in the Lancaster, PA area. This article was authored by Matthew Steger, ACI - owner of WIN Home Inspection in Lancaster, PA. No article, or portion thereof, may be reproduced or copied without prior written consent of Matthew Steger.