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Wet Summer = Wet Basement?

Here in Upstate NY we have had a wet summer. More rain than average has fallen in Albany for July and it seems to be keeping pace for August. Our lawns and gardens aren't complaining but our basements might be. Do you have moisture in your basement? Even if you don't have standing water after a heavy rainfall, is there a musty odor to your basement? In addition to being unpleasant, water in your basement can cause costly problems too. Here is a photo of a quite moist brick foundation wall covered in black mold:

Mold in basement

Before you plug in a dehumidifier and call it a day, you may want to read further. If you are not addressing the cause of the problem you may just be addressing the symptoms. Ask yourself:

1. "How is water getting into my basement?" If you can see evidence of water can you trace it an entrance point? Take note of where you see evidence of moisture and note it. Efflorescence is a white powdery deposit found on the inside surface of foundation walls. When moisture passing through the wall carries minerals and evaporates, efflorescence is left behind. Here's a photo of efforescence on a block foundation wall:


2. "What kind of foundation do I have?" Poured concrete is generally the best at keeping moisture out. Sealing a foundation is generally done during construction and becomes involved if you are trying to do it after the fact. If you have block, brick or stone there is a higher chance that moisture under pressure will find its way in.

3. "Do I have cracks in my foundation?" Cracks can be sealed by a variety of products out there without having to call a contractor. Just make sure you understand the instructions and limits of the product. If you have cracks that are bigger than 3/8", are horizontal, or show displacement of the foundation, you may have a bigger problem on your hands. In this case, it is best to get a professional opinion as the structure of your house may be in jeopardy. Here is a crack in a block foundation:

Crack in block

4. "Do I have gutters installed?" Gutters are the singlmost effective way of dealing with basement moisture. Many folks don't realize gutters do more than carry roof runoff down to ground. They also keep your foundation dry when they are clear and working properly. An inch of rain over 1500 square feet of roof area corresponds to 1000 gallons of water. In addition to gutters, you should have downspout extensions that are long enough to carry water away from your house. Many folks never install them or take them out to mow but 6' is generally enough to do the trick. Here's a missing downspout and then downspouts with adequate length extensions:

Missing downspout
Downspout extensions

5. "How is the grading around my foundation?" Is it shedding water away or towards my foundation? You may see a correspodence between where you see moisture in your basement and the slope of your yard. Re-grading can sometimes be a chore best for suited for heavy machines but anything you can do to ensure water is carried away from you house should show a decrease in basement moisture. Here is a pic of the rim joist area in a basement where the backyard is sloped toward the foundation. The resulting moisture in the basement has caused the growth of this mold-like substance:

Mold rim joist

6. "Do I have adequate basement ventilation?" Folks often forget that basement windows don't just allow in natural light, they open for a reason! As a Home Inspector I see many a boarded up basement window. These are usually the homes with moist basements. Try to keep you basement windows open during the warm season for as long as comfortably possible. A nice cross breeze in your basement can take away as much water as a dehumidifier without the high electric bill. If you happen to have basement windows which allow moisture into the basement whether from a lack of window wells or the surrounding grade, fix them. Here's a photo of a boarded up basement window:


When suggesting how to tackle basement moisture problems, I suggest the following order:

1. Make sure gutters are installed and working.

2. Ventilate the basement.

3. Repair cracks as necessary.

4. Site grading.

5. Dehumidify if necessary.

Sometimes I find folks try to seal out moisture on the inside surface of the foundation wall with a product like DriLok paint. This may be somewhat effective at keeping the moisture from evaporating into the basement air but it also traps moisture inside the wall material. I've notice that in brick and block foundatations, the high moisture level can actually cause these materials to lose their integrity and crumble. In this case, I would rather have a sound foundation and put up with the musty odor. Here's a photo of some crumbly mortar that has been painted with DriLok type paint:

drilok crumble

As always, feel free to contact Hollis Home Inspection with questions or concerns. We'd love to hear from you: email us at or call us at 518.421.6069

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