How Much Does It Cost to Waterproof a Basement or Foundation?

Before You Start: Waterproofing vs. Damp Proofing

Basements require serious moisture control because they sit below grade, so it's crucial to understand the difference between the two primary types: waterproofing and damp proofing. Waterproofing aims to totally seal the basement to prevent any kind of water leakage, whether from rain, groundwater, or humidity. On the other hand, damp proofing works to prevent the basement from absorbing soil moisture. 

Most basements feature some form of damp proofing since most building codes require it. There are various methods for erecting a damp-proof barrier, including coatings, wraps, joint fillers, flashing, dry rods, and sheeting. Damp proofing typically costs $3 to $6 per square foot compared to around $5 to $10 cost per square foot for thorough waterproofing. Because damp proofing doesn't protect against actual water leakage, the additional price for waterproofing may be a wiser investment.

Waterproofing Basement Cost Factors

Waterproofing costs can vary significantly from basement to basement because many factors will influence the final price you pay. Read below for more in-depth information on major cost factors.

Interior vs. Exterior

Some methods of basement waterproofing are performed inside the basement with a sealant applied to the interior walls, while others focus on preventing water from penetrating the outside and work to seal the exterior. Exterior waterproofing typically involves excavating the foundation and adding sealant or installing a waterproof membrane. 

Exterior waterproofing is complex work, often requiring specialized equipment and training. It’s also more expensive than interior waterproofing, with even the lowest-priced solutions averaging a total price of $1,000.

Basement Size

The size of your basement is one of the most important factors in determining the final cost of the job, with each square foot of space requiring additional materials and labor hours to complete. On average, expect to pay between $5 and $10 per square foot. 

Sealant Used

The total cost of a basement waterproofing job will be primarily determined by the sealing method you choose. If you're just coating the interior with waterproof paint as a DIY job, you'll only pay between $30 and $40 for each gallon of paint, plus the small cost of any additional supplies you need. On the other hand, if you need to hire pros to excavate and install a waterproof membrane around the foundation, you could pay as much as $15,000. 

Labor

When you hire basement waterproofing pros, they usually offer a rate that covers material and labor together (between $5 and $10 per square foot on average). The cost breakdown will differ depending on the waterproofing method employed, but generally, labor fees alone will account for between $3 and $8 per square foot. 

Foundation Improvements

Repairing a foundation costs around $4,530, or about $2,030 to $7,100. Cracks and holes in your foundation occur naturally over time but can lead to significant moisture damage. Even a durable concrete foundation can collect moisture inside the blocks. Waterproofing methods can't effectively address these issues until a pro repairs the foundation first. 

Overall Home Age

The age of your home could also influence the cost of waterproofing. If the house was built before building codes started requiring foundations to be built with footings, which are supports typically made of concrete and rebar that secure the foundation in the soil and more evenly spread the structural weight, you could pay significantly more for exterior waterproofing since it's more complicated to direct water away from your home without them. 

Potential Repairs

A leaking basement isn't merely the result of insufficient waterproofing, but it can indicate a bigger problem, like cracks in the walls, floor, or foundation. In many cases, making the repairs necessary to correct such an issue will exceed the cost of waterproofing alone. The cost of repairing a foundation depends on the extent of the problem:

• Narrow crack: This can be filled for as little as $250.

• More extensive repairs: This can cost more than $10,000. 

• Wall repairs costs: This can cost around $790.

• Cost to repair floors: This can cost $250–$800. 

Potential Mold

Leakage or dampness in the basement can very quickly result in mold. If you see or smell signs of mold growth when you descend the basement stairs, it’s time to hire a mold remediation pro near you to remove the dangerous fungus. In a basement, removing mold costs between $500 and $3,000.

Water Table Level

Determining the steps necessary to keep your basement dry involves considering local topography since homes built in different locations will face unique challenges in keeping moisture at bay. If you live in an area where the water table is high, you may need to employ more elaborate exterior waterproofing methods, both to prevent leaks and to satisfy local building codes. 

Drainage

In addition to sealing, it also makes sense to route out any water that still finds a way in. From floor drains to sump pumps, basement drains cost around $700 to $5,200.

Landscaping

Water that doesn't drain from your lawn property could threaten your foundation. Removing standing water costs between $1,000 and $3,000, while resloping a lawn costs around $1,400 to $5,200 and can also help with drainage.

Gutter Changes

Though your gutters sit on your roof, one of their key functions is to keep your basement dry by directing large volumes of rainwater away from the foundation where it would otherwise fall. Leakage and moisture problems in the basement could result from poorly pitched, damaged, or clogging gutters. The cost to install gutters ranges from $600 to $1,550, with most homeowners paying $1,050 for the job.

Excavation

Several basement waterproofing solutions require excavation and may be necessary because contractors can't access the basement from the inside. In other cases, the problem primarily can stem from water leaking through the foundation, entailing exterior sealing. Expect the costs of land excavation to fall between $50 and $200 per cubic yard of dirt. In some cases, it's a manageable DIY job, but you'll need specialized equipment costing around $75 to $350 per day to rent. Depending on accessibility, it should only take two to three days to dig out the foundation.

Exterior Sealing Methods

When keeping water outside of your home, start by consulting a pro. After the initial consultation, you'll better understand what steps to take to keep your house safe and protected. The consultation may suggest measures to address the exterior of your home's foundation. Even if you only have a crawl space, it's vital to prevent water from coming in. Because of access issues, sealing your crawl space can cost between $1,500 and $15,000.

Cement

A cementitious solution is a thick coat you can apply directly to your exterior walls and probably the easiest way to keep water out. In fact, anyone with painting experience can apply it. A 5-gallon bucket of dry cementitious solution mix for cement waterproofing costs about $40 and covers 100 square feet of your foundation. Add professional labor and additional work in patching cracks, and you'll pay about $1,000 to $1,500 for cement waterproofing. It works equally well for crawl spaces and full basements. 

However, this option is also the most inflexible. Because cement hardens completely, any joint movement or developing cracks will compromise its effectiveness. As a result, foundations in dry climates with sandy soil, which doesn't significantly expand or contract, tend to respond better to this option.

Waterproofing Membrane

Adding a waterproofing membrane is one of the more expensive options, but in many cases, it's also the most effective. When adding drainage panels and including the cost of excavating, installation of this membrane can cost up to $15,000. These membranes consist of rubberized asphalt, which is laminated to a waterproof polyethylene film. It's unforgiving and needs to be installed just right, which is why this job is best left to the pros. 

When installed correctly, this option's flexibility and durability might be the perfect fit for your basement, particularly in wet climates with expanding clay soil. It isn't used as frequently for crawl spaces as for full basement waterproofing, but its functionality remains similar.

Weeping Tiles

There's also the option of removing the water before it can seep into your walls. The cost to install a weeping tile system (also called a French drain) on your home's exterior walls is around $1,000 to $10,000, depending on the excavation depth and location accessibility. Despite the name, weeping tiles are actually plastic pipes with regularly punched holes. Water that would otherwise enter your walls instead enters these pipes, where it's guided away from the home. 

Exterior weeping tiles can function well for concrete foundations, basements, and crawl spaces, especially in damp climates. With the proper installation, grading, and materials, this may be the most sustainable and successful option for your home. You can install a weeping tile system in addition to cement and membrane options.

Bentonite Clay

A natural sealant, sodium bentonite is a material similar to clay that you can mix with the dirt surrounding your foundation, where it absorbs water and swells up to fill cracks. Some contractors advise against this method since it can lead to unintended consequences, such as clogged drains. Also, some building codes prohibit its usage. You'll pay between $3 and $4 per square foot to apply it.

Interior Sealing Methods

There are a variety of different means by which you can waterproof your basement from the inside. We discuss all of your options below.

Concrete Waterproofing & Foundation Coatings

A thick, permanent concrete coat can help keep the water out of your basement, even if it gets through your exterior barriers. Expect to pay around $500 to $1,000 for professional interior concrete waterproofing. Coating costs less in labor compared to other sealing methods because no excavation is needed. 

In addition to a simple coating, you can use a product like Perma-Seal epoxy sealer to protect your basement. This acrylic/epoxy mixture provides an incredibly durable solution that improves the life of your concrete floors and walls in addition to their seal. When done by pros, it'll cost you between $3 and $12 per square foot, depending on the location, product, and prior repairs needed.

Silicate Concrete

Paint

Perhaps the simplest way to keep the interior walls of your basement dry is to paint them with the right paint, typically acrylic, giving it the bonding it needs to keep the moisture away. Think of this option as a thicker version of everyday paint. One gallon of this basement paint is about $30 to $40 and covers approximately 75 square feet. More expensive solutions like Ever Dry, designed for professional use, cost about $150 per gallon for the first coat and about $275 per gallon for the second coat. You'll need both coats for the paint to work.

Vapor Barrier

You can also install a vapor barrier if you have a crawl space, which is at higher risk for water damage because it’s typically less protected against leaks and moisture. At its core, a vapor barrier is a plastic sheet designed to prevent moisture from penetrating the house. But installing it can get tricky, so it makes sense to work with pros. Depending on its size and the sheet thickness, professionally installing a vapor barrier in your crawl space can cost between $1,500 and $3,000. 

Baseboard Channels

If you’ve got block walls, you can install channels in the baseboard that function like gutters, draining water away from the house. Contractors charge around $30 per linear foot to drill weep holes in the walls and put in the channels. 

Subfloor Drain Tiles

Another option is to install a drain tile system in your basement subfloors. These waterproof, interlocking tiles can be placed an inch or two beneath the finished floor on the surface of a concrete slab subfloor. Expect to pay between $25 and $55 per square foot. The drainage system directs water away from your home, preventing liquid from accumulating in the basement. But it doesn't prevent moisture from entering through the air or walls, so the tiles need to be combined with another moisture-proofing solution. 

Interior French Drains

While outdoor French drains (or weeping tiles) are more common, you can also install them in your basement’s interior. The drains are typically placed around the perimeter of the basement, collecting and delivering excess water to a sump pump or pipes that bring it away from your home. You’ll pay around $60 to $120 per linear foot.

Alternatives to Waterproofing Your Basement

There are also a number of tools and strategies with which you can mitigate the need for or supplement more elaborate forms of interior and exterior basement waterproofing. 

Dehumidifiers

Dehumidifiers offer a solution for moisture problems around the house. The cost of a basement dehumidifier falls between $800 and $1,200. Such a unit will keep moisture levels healthy, below 55%, and provide a great alternative for minor humidity problems. However, if you have a more serious issue causing water to leach into your basement, a dehumidifier can make things worse by drawing in additional moist air. 

Window Well Drains

In some cases, leakage and excess moisture in a basement result from poorly designed window wells that allow water to pool. You can install window well drains—a highly effective solution for this issue—at around $500 to $2,000. 

Sump Pump

A sump pump is an essential weapon against basement flooding. It sits at the lowest point in your home (a small pit called the basin), which collects excess water from the house. When the water level gets high enough, the pump is activated, using electricity to push the water out of your home and into a nearby storm drain. Many larger waterproofing solutions include a sump pump, but if you need to add one to your home, you’ll pay $1,290 on average.

DIY vs. Hiring a Professional

Some basement waterproofing methods are very DIY-friendly, while others should always be left to the pros. If you're experienced and comfortable making home repairs, you can address small problems like cracks on your own, as well as take on some of the more straightforward interior waterproofing methods, like paint and concrete sealers. But fully waterproofing the basement is a significant project that must be done right: There's little room for error and high costs if you make the wrong move. 

Many manufacturers of larger basement waterproofing systems won't extend their warranty unless a pro installs the product. It's also essential to hire a local basement waterproofing pro if you're not sure about the source of your moisture. A good contractor can be relied upon to determine the nature of the problem and recommend the most appropriate solution.

FAQs

What is the least expensive way to waterproof a basement?

Interior waterproofing methods offer the most affordable solutions, with waterproof paint costing around $30 to $40 per gallon and silicate concrete sealers going for $0.15 to $0.25 per square foot. But these forms of waterproofing are only appropriate for specific problems, and if your basement moisture results from more persistent issues like a cracked foundation, you’ll end up paying more to fix them. 

Is waterproofing my basement worth it?

Yes. The damage and costs resulting from water damage can be significant. On average, homeowners spend $3,150 in costs to repair water damage in their home, but that can range as high as $5,100 or more. Taking proactive measures is an investment that prevents these prices from ever hitting your wallet.

How long will it take to waterproof a basement?

The time required to waterproof a basement depends on the selected method. Some approaches to interior waterproofing, like paint or sealant, can be completed within a day. Installing new drains or weeping tiles will need at least two to three days of labor. Any forms of exterior waterproofing that require you to excavate land will require an additional three days of work to prepare the ground. 

Does waterproofing a basement increase the value of a home?

The basement is often a top consideration for potential homebuyers. If yours is damp and leaky, it’ll certainly put a lower ceiling on bids and could ruin the deal entirely. If you’re considering selling your home in the near future, putting the time and resources into finding and implementing the right basement waterproofing solution can bring a healthy return on investment.