HELP! I Have A Wet Basement
Traditional basement damp-proofing methods do not last and wet basements have become the most frequent complaint of homeowners. What to do?
If your basement is already wet and leaking water, you could hire a waterproofing company to install french drains with a sump pump. Alternatively, the contractor may recommend excavating down to the footers and waterproofing the foundation walls on the outside.
Excellent choices, but these waterproofing solutions are not cheap!
When your basement is leaking enough water to be worried about, a homeowners first move is to call on a local basement waterproofing service. A technician will then recommend waterproofing solutions from the outside, inside, or both. On average, exterior waterproofing will run you north of $15,000. Installing interior perimeter drains with a sump-pump could cost a homeowner up to $11,000. You may be asking yourself, “Could I potentially waterproof a wet basement myself? I am not what one would call a do-it-yourselfer.”
Locate Where the Water is Coming From
The first line of basement waterproofing defense should always be made on the outside and knowing how the water is getting inside:
Outside – Divert rainwater away from the foundation walls by proper grading, gutter maintenance, downspout extensions, window well covers, caulking corners, gaps, and cracks. Apply penetrating sealers to the exterior concrete, brick, pavers, and porous masonry. Simple steps like these can go a long way to achieving a dry basement, but by no means are they the end-all solution.
Inside – Locate the source of water entry inside the basement. Knowing the reason why your basement is leaking can make a do-it-yourself basement waterproofing project surprisingly simple and inexpensive.
How To Waterproof Wet, Leaking, Damp, Foundation Walls
Foundation walls will appear wet or start seeping water only intermittently after heavy rains. You may also notice spots of efflorescence (white “powder” or “whiskers”) on the concrete surface which is a telltale sign of capillary water and water vapor. If this sounds all too familiar, now is the time to act before your wet basement gets worse making repairs much more difficult to do.
If your foundation walls are already damp, allow the concrete to dry out for the best basement waterproofing results. You can speed up the drying time by drilling weeping holes in the bottom of concrete blocks, installing a fan in the basement to improve evaporation, or simply waiting for dry weather. Once the concrete is sufficiently dry, seal the porous concrete foundation walls with RadonSeal Penetrating Concrete Sealer.
Why RadonSeal? RadonSeal is not your average cement waterproofing sealer like those found in big box stores. Waterproofing paints, cementitious coatings, and membrane coatings will eventually loosen, crack, or peel, as they are pushed off by hydrostatic water pressure, trapped water vapor, and efflorescence. It could take a couple of years, but eventually, all waterproofing paints or coatings will fail, requiring another application. A big problem if you have already finished the basement!
RadonSeal is different. Negative side water pressure and efflorescence cannot budge it. Once cured inside the concrete the internal seal is PERMANENT, which is backed by an unmatched limited lifetime Money-Back Warranty. RadonSeal works by penetrating deep into the concrete (up to 4″), chemically reacts with lime and alkalis, expands inside the pores, and cures as a mineral. It waterproofs concrete internally against water seepage, water vapor, and even against radon gas. RadonSeal combines concrete waterproofing, damp-proofing, concrete preservation, and radon mitigation in one sealer!
Sounds too good to be true. What’s the catch? There is none. RadonSeal does not change the appearance or surface profile of the concrete. It does not contain chemical solvents, is non-corrosive, has ZERO VOCs, and can be easily applied using a hand-pump “garden or bug” sprayer.
If you want a painted basement wall, you can always apply waterproofing paint after you have deep-sealed the concrete with RadonSeal. That will protect the waterproofing paint against water, moisture vapor, and efflorescence.
How To Waterproof Damp Concrete Floors
Many homeowners have found out the hard way that paints and coatings alone are just not suitable for concrete floors. Latex-based waterproofing paints are too soft for floors. And if you apply an epoxy or urethane coating, concrete floor paint, or concrete overlay, years of water vapor pressure and efflorescence coming through the concrete will eventually make it fail, crack, or peel.
Seal Your Basement or Garage Floor Against Water Vapor Transmission – The proper method is to deep seal the concrete floor first with RadonSeal Concrete Sealer. RadonSeal provides the permanent waterproofing solution for concrete slabs by stopping capillary water seepage due to hydrostatic pressure or wicking water. It also restricts the inflow of water vapor through the pores. It practically eliminates efflorescence and concrete dusting. RadonSeal does not change the surface appearance or profile, leaving the concrete suitable for paints, adhesives, tiles, flooring, epoxy, and coatings. It is a great primer!
How To Repair A Leaky Concrete Floor Crack – A popular method is to route out the crack 1/4″ wide by 1/2″ deep and fill it with self-leveling caulk or hydraulic cement. But the caulk or hydraulic cement are certain to get loose and you have to route it out again.
Instead, permanently repair the crack using CrackWeld Concrete Floor Repair Kit. It provides a strong, full-depth repair of cracks in concrete slabs, be it hairline or 1/2-inch wide. Stronger than concrete – the crack will not move, get longer, or wider. And there is no need to chase the crack before application.
Foundation Crack Repairs Made Easy
Most homes, both new and old, develop a crack or two in foundation walls. If the cracks aren’t leaking, it is only a matter of time until they do, as the exterior waterproofing coating gradually deteriorates. So, if your basement cracks are not leaking yet, now is the time to repair them to avoid water damage and mold growth.
Repairing cracks yourself may appear to be a daunting task but surprisingly, it is quite easy. RadonSeal DIY Concrete Crack Repair Kits or Professional Kits allow you to repair cracks in poured concrete walls like a pro! You will save $100’s and the repair is permanent!
Water Seepage through a Leaky Floor-to-Wall Joint
The most common complaint from homeowners is; “Water is coming up from the corner floor-to-wall joint!” or “There is lots of water pushing up from underneath the slab!” However, this is usually not true.
In most cases, while the water migrates through a poured concrete wall, it sinks and comes out at the bottom of the wall. In the case of concrete blocks, the hollow cavities fill up and the highest pressure is at the bottom of the water column. This seepage makes it appear like the water is coming up from the floor-to-wall joint. The solution is usually easy – seal the walls with RadonSeal to stop the water migration.
Sometimes, water building up outside the foundation seeps through the joint where the wall sits on the footing and then up through the floor-to-wall joint. The solution to this problem would be to chase the joint 1/2″ deep with a hand-held grinder and fill the joint using ElastiPoxy Joint & Crack Filler Kit (to provide a flexible joint). Alternatively, you can avoid having to use a grinder and inject the joint with our Easy-Peel DIY Foundation Crack Repair Kit – more expensive but the expanding polyurethane will also seal the leaky wall-to-footing joint.
In rare cases, water actually comes up from underneath the slab and at the same time, it will also seep through any cracks or expansion control joints in the floor. It may push through the pores in the concrete and in the most extreme cases, form hissing mini-geysers on the floor. The solution is installing a sump pump to relieve the hydrostatic water pressure and sealing the floor with RadonSeal Concrete Sealer.

Waterproofing Stone or Brick Foundations
Many older homes have foundations constructed of limestone, sandstone, or fieldstone. The weak link in these types of foundations is the porous, soft, and crumbling mortar. It provides an easy avenue for water seepage which gets worse and worse as the mortar deteriorates.
Stone Foundations – First remove any loose or crumbling mortar with a wire brush or a wire wheel attachment for an electric drill. If needed, repoint the mortar filling small fissures and separations. Type S mortar is commonly used but a better option would be to use ElastiPoxy Joint & Crack Filler Kit (mixed with sand). Apply LastiSeal Brick & Concrete Sealer to strengthen and waterproof the old mortar.
For limestone and sandstone and foundation walls use RadonSeal. RadonSeal will react inside limestone and sandstone, and strengthen the surface against crumbling and dusting.
Brick Foundations – To properly waterproof clay brick walls (like Chicago brick) use LastiSeal Brick & Masonry Sealer. Like RadonSeal, LastiSeal penetrates deep into porous bricks and mortar but it cures as a plastic. The seal will never peel or crack because it does not form a surface film. It holds back hydrostatic pressure and will also strengthen and harden the bricks and mortar.
Once cured, the waterproofing seal will be practically permanent. There is no similar product compared to LastiSeal sold on the marketplace today!
Do-It-Yourself Solutions that Will Save You $1,000’s
Whether you need to waterproof a new or old basement, damp concrete floor, wet concrete block wall, crawl space, stone foundation, or leaky brick wall, RadonSeal has a long and well-proven history (est. 1997) of providing expert customer service and the most advanced, professional-quality basement repair products on the market. Our line of Waterproofing Sealers, DIY Foundation Crack Repair Kits, Concrete Floor Crack Repair Kits, Mortar & Joint Repair Kits are not only for professionals but also easy enough for use by the average homeowner.
Instead of investing in cookie-cutter waterproofing systems, which may not perform well or for very long, do-it-yourself basement waterproofing can be accomplished with a little know-how and by using the best products for your specific basement leak(s). We guarantee you will get long-lasting results without having to break the bank on expensive waterproofing methods.
We know from over 20-years of experience that basement waterproofing solutions are not always clear-cut! If you have questions about your basement or a particular project please contact a RadonSeal technician for expert advice.
BASEMENT LEAK | SOLUTION |
---|---|
CONCRETE BLOCKS – Moisture, Water Vapor | Use RadonSeal Plus |
POURED CONCRETE WALLS – Dampness, Moisture | Waterproof using RadonSeal Concrete Sealers |
BASEMENT FLOORS – Water Vapor, Dampness | Waterproofing using RadonSeal |
FOUNDATION CRACKS – Leaky settling cracks. | Repair using DIY Foundation Crack Repair Kits or PRO Crack Injection Kits |
CONCRETE BLOCK CRACKS | ElastiPoxy Crack & Joint Filler Kit |
BASEMENT FLOOR CRACKS – Hairline, Stress Cracks | CrackWeld Concrete Floor Repair Kit |
BRICK WALLS – Dampness, Moisture | Waterproof brick and mortar LastiSeal Brick & Concrete Sealer |
MORTAR JOINTS – Separations & Cracks | Replace mortar using ElastiPoxy Crack & Joint Filler Kit |
FLOOR-TO-WALL JOINT – Cove Join Leaks | Fill using ElastiPoxy Crack & Joint Filler Kit |
CORNER CRACKS – Poured Concrete | DIY Foundation Crack Repair Kits |
EXPANSION CONTROL JOINTS – Saw Cuts | ElastiPoxy Crack & Joint Filler Kit |
PIPES & CONDUITS | Seal leaking penetrations with PipeTite Gap Filler Kit. |
WIRE TIES | PipeTite Gap Filler Kit |
MAIN SUMP PUMP FAIL | Install an Emergency Water-Powered Backup Sump Pump |
Surprising Solutions That May Save You a Bundle
Leaking Water Pipes – Is your basement leaking or sump pump always running in rain or sunshine? Suspecting a spring under your basement? Call your water company first to have them check it! The water main to your curb box or the pipe to your house may be leaking, particularly if made of plastic. Usually, the serviceman will detect slight hissing in the pipe entering your basement.
Clean the Exterior Footing Drains – Footer drains, which are crucial to relieving the water pressure on your foundation may get clogged by silt or tree roots. If there is access, hire a contractor to clean them using high-pressure water jetting or with an auger snake. Old clay tiles may have collapsed and just a small section may need replacement.
Clean the Floor Drains – Make sure the floor drain is not clogged. Some experts recommend getting the entire drain cleaned by a drain cleaning company on an annual basis. Make sure that the drain has a U-trap filled with water so it does not let in soil gas, water vapor, and radon gas.
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Basement Waterproofing Companies
Solutions proposed to homeowners by basement waterproofing contractors typically require intrusive and expensive work. Each method has its pluses and minuses. None, however, provide a solution for both basement walls and floors, and all cost much more than using RadonSeal basement waterproofing products:
Hollow Baseboards – A plastic channel system (“interior gutters”) glued around the perimeter of the floor to collect water seeping through the basement walls and route it to a sump pump. Instead of keeping water out, it works after the water has entered – a bad idea! You cannot finish the basement walls because it would trap all the moisture evaporating from the channels, causing molds and mildew. It does not do anything against water seepage through the floor. Usual cost $5,000 to $10,000.
Floor Perimeter Drainage Gap – A “floating slab” design with a wide gap (1/2″ or more) around the floor in order to allow water seeping through the walls run down below the slab. A very bad concept! The walls should be built waterproof in the first place. The gap will let in tons of soil gas saturated with moisture and radon gas. Framing the walls would trap water vapor and lead to molds and mildew.
Sump Pump – Sump pumps relieve excessive water pressure by draining the gravel bed underneath the slab. Note: Not effective for leaking basement walls. Digging the pit and installing a sump pump will costs several $1,000. Be sure to install an airtight cover to prevent the release of water vapor and radon into the basement. Complete reliance on a sump pump is unwise – it may fail or the power may go off. If the basement is finished, make sure to install a backup sump pump to protect your investment.
Interior Footing Drains – The perimeter of the concrete floor has to be jackhammered, a perforated pipe is laid in gravel next to the footings, and a concrete cap is poured over the pipe (expect 1/2-inch of low-quality cement). The French drain carries water to a sump pump. Do not leave a gap next to the walls because it would let in vapor and radon. Usual cost is around $12,000, including the sump pump. It will reliably drain the gravel bed underneath the slab. But if there is no gravel or it is silted up, the center of the floor may still wick water. And it will do little for seepage through basement walls.
Exterior Waterproofing – This is a big job! It requires removing landscaping, excavating down to the footers, laying new perimeter footing drains in a bed of gravel, cleaning and waterproofing the walls, protective resin boards, drainage gravel, and backfilling. Since tar coating on concrete walls cracks and breaks down, use a rubberized (polymerized) membrane waterproofing coating, or a dimple drainage board over a dampproof coating (dimpled plastic sheets). The usual cost will be in the proximity of $25,000, but will do little for water seeping through the basement floor and foundation coatings are not permanent.