It’s not hard to notice when your basement feels damp. It should be a bit cooler when you go down there, but when moisture gets in, the air turns wet and heavy. You may have damp basement walls too, especially after a Carolina downpour.
Basements sit below ground, so it’s pretty easy and common for water to find its way in. It could be through a hairline crack, a window well, or the pores in the wall itself. As a home settles, cracks can open in the wall’s exterior waterproofing, and once the soil outside gets saturated, that water pushes through. Left alone, that invading moisture can result in a musty smell, peeling paint, and eventually mold in your basement.
High-quality dehumidifiers can pull the excess humidity out, but the more important, longer-term fix is waterproofing the walls themselves.
If you’re wondering how to keep a basement dry without a dehumidifier, that’s what the following tips are for, starting with finding out where the water’s actually coming from.
Jump to:
Determine the source of the water
Concrete is porous, so the wet spots on your basement walls will tell you where the water is coming in. Look for streaks at window corners, cracks at mortar joints or where pipes enter or exit your home through the foundation. If your entire wall is wet, you’ll need to do a condensation test. This involves drying an area of your wall, then attaching a one-foot square of aluminum foil using duct tape. After 24 hours, check the backside of the foil. If it’s damp, water is seeping in from the outside. If it’s dry, it’s coming from other places in your basement.
Don’t make repairs with standing water
It’s tempting to make repairs while you’ve got standing water in your basement, but it’s vital to remove the water first. Cracks in basement walls may have allowed the water in, but working in those conditions can increase your chances of electrocution. Turn off the basement power, then use a utility pump to remove the water into your yard. Once the basement is dry, start inspecting, fixing and waterproofing the basement walls, so that you’re not dealing with excessive moisture and hazardous conditions.
Address window well leaks
Window wells in basements commonly cause leaks, because if they’re not drained properly and maintained, they can end up with water pooling in the wells and leaking through the windows. Though it’s hard to install drainage after installation, digging a couple of feet lower in that area and filling it with gravel to improve drainage can help the process. Then, caulk around the window with a caulk suitable for masonry and install a sloped window well cover to keep rainwater away from the window well.
Add masonry waterproofing products to bare interior basement walls
If your condensation test showed that water was coming through your basement walls, use high-quality waterproofing basement paint. A combination of a basement waterproofing sealer and paint, it applies like paint will to keep your basement dry. Once it's completely dry, it creates a watertight seal to keep moisture out of your basement space, making it a much more comfortable and drier environment to enjoy.
Don’t apply sealant over painted walls
If your basement walls are already painted, you’re going to have to remove that paint prior to adding sealant, because sealant only sticks to bare masonry walls. If there are several layers, hiring a blasting contractor to sandblast the walls may be faster, but it can also be handled by wire brushing the walls yourself. Efflorescence, or white deposits that form on damp concrete walls, must also be removed using muriatic acid, following the manufacturer’s directions.
Keep water away from your basement
If you keep water away from your basement walls, it's easier to keep everything dry. That means removing foundation plantings that need watering, and inspecting and repairing gutters, downspouts and similar items that direct water away from your home. Consider grading your yard away from the foundation using a minimum of a 2% slope.
You could also install exterior drain tile, which can be expensive, but is very effective, and have a waterproof membrane installed as exterior basement waterproofing, and add a sump pump to move the water that does drain away from your home.
When DIY Isn't Enough
These six tips can solve a lot of basement moisture problems, but not all of them. If water keeps coming back after you've addressed the source, sealed the walls, and fixed the downspouts, the problem is bigger than a wall treatment can fix.
A few signs it's time to call a professional: water returns within a season of a DIY fix, a crack keeps growing, standing water shows up after normal rain and not just storms, or a musty smell won't go away no matter how much you clean.
At that point, you're likely dealing with a drainage issue below the surface, not just a wall that needs sealing.
For a full assessment of what's causing your basement moisture and what it'll take to fix it, see our basement moisture control services.
Everybody wants their basement to be a comfortable, enjoyable space that can be used for fun, storage, or both. But living in the Carolinas, unwanted moisture can get in the way. And once it finds a pathway in through the basement walls, it won’t stop. Hopefully, this article has given you some insight about what to do when that happens.
If you're not ready to take on the work yourself, which is totally understandable, Moisture Loc is here to help. We’ve been saving basement walls in Charlotte and the surrounding area for nearly 40 years. If you fear you have damp basement walls or any other sign of moisture in your house, schedule a free inspection. We’ll be happy to take a thorough look and let you know what’s going on.
FAQs
What's the best sealant for basement walls?
A masonry waterproofing sealer made for concrete and block stops water. Regular paint does not. The sealer needs to go on bare masonry, so any old paint or efflorescence has to come off first. Look for a product labeled for basement or below-grade use, not just general exterior paint.
Will painting basement walls stop moisture?
Regular paint won't stop moisture, and it can make the problem worse by trapping water behind it. A basement waterproofing sealer is different: it's designed to bond to bare masonry and create a watertight seal. If your walls are already painted, that paint has to come off before a sealant will bond and work.
Interior or exterior waterproofing — how do I know which one I need?
Interior sealants and panel systems manage water once it's already coming through the wall. Exterior waterproofing, like drain tile and a waterproof membrane, stops water before it reaches the wall at all. Interior fixes are less invasive and cheaper upfront; exterior fixes address the source but cost more and involve digging around your foundation. A lot of basements need both.
Why does my basement still feel damp after I sealed the walls?
Sealant handles water coming through the walls themselves, but it won't fix humidity in the air, a grading problem outside, or a leak somewhere the sealant can't reach, like a window well or a growing crack. If it's still damp after sealing, the moisture is probably not coming through the walls, but through a pathway the sealant didn't address.
