Ashburn, VA

How Much Does It Cost To Waterproof A Basement?

$3 – $9 Per Square Foot
$1,920 – $6,320

Waterproofing a 1,000 sqft. basement costs $4,118 on average, or about $3 to $9 per square foot, which includes sealing interior and exterior walls. Minor repairs and crack filling costs $1,500, while complete drainage improvements range from $2,000 to $6,000. Some waterproofing contractors charge on a per project basis, or per linear foot. Get free estimates from basement waterproofing companies near you.

Basement Waterproofing Cost

The average cost to waterproof a basement is $1,920 to $6,320, or between $3 and $9 per square foot for materials and labor. Interior basement repairs that don't require excavation cost around $500 to $1,500, whereas large extensive repairs with drainage and foundation issues run $10,000 or more.

Average Cost To Waterproof a Basement Chart

Waterproofing includes planning, preparation, sealing the foundation, waterproofing walls with cement, installing a sump pump or perimeter drain, diverting downspout runoff away from the foundation, and an epoxy injection to repair cracks.

Basement Waterproofing Cost
National Average Cost $4,118
Minimum Cost $250
Maximum Cost $20,000
Average Range $1,920 to $6,320

Most water problems in a basement stem from ineffective gutters and downspouts, poor drainage around the foundation, clogged or nonexistent drain tiles, or a poorly laid foundation that wasn’t poured on graded soil. The first step to waterproofing is applying a protective seal or membrane.

A wet basement can affect the foundation, support beams, and walls, and it can cause serious health problems if mold and mildew develop. Small do-it-yourself waterproofing and repairs are possible, but you'll likely need a professional waterproofing contractor to ensure your basement doesn't flood or have moisture problems in the future.

Table of Contents

  1. Average Cost to Waterproof A Basement
  2. Exterior Waterproofing
  3. Interior Waterproofing
  4. Other Foundation Waterproofing Costs
  5. Basement Waterproofing Systems
  6. Causes of a Wet or Damp Basement
  7. Frequently Asked Questions
  8. Basement Waterproofing Companies Near Me

Basement Waterproofing Cost Per Square Foot

Basement waterproofing costs an average of $3.50 to $6.50 per square foot, with more thorough waterproofing methods ranging from $5 to $9 per square foot. Pricing can be considerably different from one aspect of waterproofing to the next, depending on the extent of the leak. For example, do you need to excavate, or waterproof both the interior and exterior, or install extras such as a sump pump, or all?

Exterior Basement Waterproofing Cost

The average cost of waterproofing your basement from the outside with a coating or membrane is $3 to $6 per square foot, which typically includes materials and labor costs. The liquid or sheet membrane keeps water from penetrating the basement walls.

There are numerous waterproofing solutions to seal your foundation, such as using cement (cementitious), installing an exterior membrane, or weeping tiles to redirect any water buildup or dampness. This guild will help you learn the differences between each method, but, always consult with an experienced professional, so you know precisely what steps to take.

Waterproofing vs. Damp Proofing

Basements are typically damp proofed at an average cost of $3 to $6 per square foot which includes excavation. For more thorough waterproofing solutions, expect to spend $5 to $9 per square foot or more. Here's the difference between each:

  • Damp proofing is excellent for areas with high humidity but not a lot of rainfall or water pooling, and it prevents soil moisture from coming in. The dirt around the foundation will need to be removed so that the damp proofing coating can be applied.
  • Waterproofing was created for cinder block and poured foundations—to keep moisture out of these thick materials. Because waterproofing protects against heavier waters, it is best for areas with a high water table. Waterproofing is meant to block moisture and heavier liquids (rain, flooding, runoff, etc.)

Damp Proofing Membranes Installed Around Basement Foundation

Cost To Seal A Basement

The average cost to seal a basement or foundation is $1,500 to $4,250, plus the excavation cost, which is typically a minimum of $3,000 to remove the soil to gain access to the foundation.

The foundation sides and basement walls in direct contact with surrounding soil can be sealed to protect them from water seeping in. While concrete is good at not absorbing water, it can absorb moisture. Below are the different waterproofing methods that can be applied to concrete or masonry walls which don't include excavation or backfill.

Cost To Seal A Basement Per Square Foot Chart

Cost To Seal A Basement
Sealant Cost Per SF Installed
Cementitious $5.25
Liquid Membrane $3.34 – $5.76
Sheet Membrane $3.35 – $6.52
Sodium Bentonite Panels $3.53

Cementitious Waterproofing

Cementitious waterproofing your basement costs $5.25 per square foot for the cement and professional labor. Cement waterproofing also works great for patching cracks or sealing a crawl space. A cement solution is a thick, durable coating that is easy to apply, provides a smooth look, and can be painted on.

A significant drawback of using a cementitious solution is that the cement is not flexible and no give to it. If there is any joint movement or cracking, then it won't be as effective. However, it will stand up just fine to water exposure and is typically used in dry climates.

One gallon of cementitious liquid solution costs about $36 and covers up to 150 square feet. An acrylic additive will make the mix longer lasting and bond better. You'll have to buy this separately. Two coats are preferable on most surfaces for waterproofing purposes.

Foundation Waterproofing Membrane

A more costly solution than a cementitious coating is a waterproofing membrane; however, it will be much more powerful. Installation of a membrane requires excavating and adding drainage panels to block the water from seeping in completely. A liquid membrane is more effective because there are no seams between panels that could leak.

Foundation Waterproofing Cost
Membrane Cost Per Square Foot Installed
MiraDRI 860 $3.35
LM-800 $3.57
Mira Drain 6200 $3.51
Quick Drain $6.52

Contractors Waterproofing the foundation with Protective Membrane

Liquid Waterproofing Membrane

A liquid waterproofing membrane costs $3.34 to $5.76 per square foot per coat to apply crystalline or elastomeric membrane, with 2 to 3 coats being the norm. The membrane keeps water from going through the walls to the inside of the basement and is available in different grades. The only downside of this is that it might be applied thicker in some parts and thinner in others unless you hire an application expert. Each manufacturer has specific instructions for waterproofing joints, holes, etc.

Sheet Membrane For Waterproofing

A sheet membrane for waterproofing can be wrapped over the concrete foundation footing, applied to the walls, and tied into a perimeter drain system at or around the footing for $3.35 to $6.52 per square foot. Usually made or rubberized asphalt, they are stuck onto the walls. Extra care is required to prep the walls, joints, and holes properly, or it won’t be 100% effective. Be sure your contractor covers the top of the basement system with at least 6 inches of soil and backfill immediately after installation.

Bentonite Clay Waterproofing Cost

Bentonite clay waterproofing costs $3.53 per square foot on average with labor added to nail one layer in place. Made of corrugated cardboard and clay, it forms a barrier between the foundation and any wet soil from outside. Since sodium bentonite absorbs moisture, it expands, filling in cracks and thus preventing water from getting in. However, unless it’s correctly installed, it will have to be completely redone if the seal doesn’t form. Waterproofing professionals say this is a temporary solution since the clay is known to clog outdoor drains.

Weeping Tile Installation Cost

Installing weeping tiles, or perimeter drain tiles, on your home's exterior walls costs $2,500 to $15,000 on average. A weeping tile system redirects any water buildup to an area away from the foundation. The price depends on the amount of excavation required and the perimeter size of the home.

Weeping tiles are not tiles, to be clear, but plastic piping perforated with holes large enough for water intake. Water enters these pipes that would usually leak into the walls. Then it is redirected toward an area that is not near the foundation. Weeping tiles are especially suitable for damp climates and can be installed in addition to membrane and cement waterproofing.

Exterior Excavation Waterproofing Cost

Exterior excavation to expose the basement for waterproofing costs $51 per cubic yard or about $100 to $250 per linear foot depending on the accessibility and depth. Most excavation contractors charge a minimum of $3,000 or more. This charge is for a two-person crew where the whole exterior of a foundation will need to be excavated. Any exterior waterproofing method such as a membrane installation or weeping tiles is going to require large-scale excavation.

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Cost of Waterproofing Basement From Inside

Waterproofing the interior walls and floor of your basement with a concrete coating costs the same as waterproofing the exterior without the considerable cost of excavating the soil. Additional options include silicate sealers, a vapor barrier, an epoxy injection to fill cracks, or waterproofing paint. Waterproofing from the inside can double the protection you have against the basement allowing water in.

Concrete Waterproofing and Foundation Coatings

The interior walls can be waterproofed with a coat of concrete mix which is applied to the walls for between $3.53 and $5.25 per square foot. This thick mixture can keep the water out of your basement even if water seeps through your exterior barriers. A concrete solution can only be applied to unpainted concrete and dries to look something like bristled stucco. In addition to concrete, other materials include crystalline or elastomeric to seal your basement.

Interior Basement Waterproofing Cost
Material Cost Per Square Foot Installed
Concrete $5.25
Crystalline $5.53
Elastomeric $4.13

Waterproofing A Basement With Bitumen Spray on Tar

Silicate Concrete Sealers

Silicate sealers have a chemical reaction with concrete to create a stable, water-resistant barrier. Silicate is a clear coat that lets moisture get out instead of locking it inside the wall. Once you add in professional labor costs, applying a silicate concrete sealer costs $3 to $7 per square foot. One gallon of concentrated sodium silicate concrete sealer, hardener, and densifier costs $65 and covers 200 to 300 square feet of cured concrete, and you’ll need to apply two coats.

You can also apply an epoxy sealer, such as Permaseal, that will enhance the durability of already applied seals on your basement floors for $3 to $7 per square foot including materials and professional labor costs. A 5-gallon bucket will cost about $150 at most hardware stores to cover 1,000 square feet, and a few coats are needed for it to be effective as a waterproofing measure. A solid epoxy cannot be used; it must be a solvent or water-based epoxy.

Basement Waterproofing Paint

Painting your basement to keep the moisture away can easily be a DIY job or done professionally for $0.61 to $0.87 per square foot, which includes cleaning and prepping the area before painting. Waterproof paints usually are acrylic and are a simple solution to working with exterior waterproofing to keep your basement dry. The acrylic paint is thicker than normal and will bond to the wall, which will keep the moisture out. If the exterior has not been waterproofed properly, the paint can start breaking down even six months after application.

Waterproof paint ranges from $10 per quart to $195 for five gallons of top quality solutions such as Everdry. As a pricing example, one gallon of KILZ Interior/Exterior Basement and Masonry Waterproofing Paint costs $32 and will cover about 75 – 125 square feet, depending on how porous the basement walls are.

Crawl Space Waterproofing Cost

Sealing and waterproofing a crawl space costs an average of $2,000 to $10,000 for professional installation depending on the size and condition of the crawl space, the thickness of the vapor barrier, the number of layers, and the type of insulation.

The cost of sealing a crawlspace may be a little higher than expected, but crawlspaces are harder to access most of the time. A crawl space vapor barrier costs $0.27 to $0.50 per square foot to install, and is a fiberglass-reinforced polyethylene sheet that prevents the moisture under the house from rising. If installed properly and well kept, a vapor barrier will last for 20 years. A vapor barrier should be installed by a professional, so no area is left exposed.

Also, consider installing a dehumidifier to remove moisture from the air. It's also an excellent time to check for and fix issues like mold, dry rot, pests, wet insulation materials, and weakened joists.

Epoxy Injection Crack Repair Cost

An epoxy injection costs $200 to $500 per crack to fill wall and foundation cracks up to ¾” wide. An epoxy injection is stronger than concrete and prevents any cracks from leaking. Application is performed from inside the basement in less than one hour per crack and cures within 5 hours.

Heavier reinforcement will be needed if the area around the exterior foundation wall experiences constant freezing and thawing. The constant change in temperature may produce future cracks, so this is not a long-term solution. Warmer climates won't typically experience this problem.

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Other Foundation Waterproofing Costs

Choosing a combination of waterproofing products, methods, and sealing solutions is the best option, especially if you live in an area that experiences all four seasons. Taking care of water damage is one of the costliest repairs you can make to a home. You'll want to do everything in your power and budget to prevent damage from occurring.

Insulating and Waterproofing Foundation - Damp Proofing Coatings & Bitumen Membrane

Interior Water Drainage

Interior drainage systems are a smart option for routing water out of your basement. The tiles will be installed along the inside perimeter of the walls or crawl space. When the water enters the tiles, it is directed to a sump pump that will push the water out into an area away from the home.

Cost of Interior Wall Drainage

Interior wall pipe drainage is usually done with polyethylene pipes, which range in price from $0.97 to $2.81 per linear foot installed. Install pipes inside the basement walls and connect them to a sump pump so the water can be pumped out. Most homeowners install a second wall over the first one to contain the pipes.

Sump Pump

The cost to install a pedestal or submersible sump pump plus the electrical work involved is between $490 and $1,170. A sump pump without the electrical or pipework will cost you about $280 as a DIY project or about $1,000 for the pump and pipe professional installation.

Sump Pump Installed In Basement With a Water Powered Backup System

If flooding is expected at certain times of the year, get a water-powered backup pump as well for a cost starting at $200. The sump pump pumps water away from the basement through pipes to an area outside, from where it won't reenter the basement or cellar.

French Drain

French drains prevent water damage by redirecting water away from the foundation and are installed beneath the surface. A plumber can install an interior french drain for $50 to $60 per linear foot, or about $300 to $1,500 on average. An exterior french drain is easier and cheaper to install at $10 to $15 per linear foot, but it's not as effective.

Basement Leak Repair Cost

Cracks in your foundation caused by shifting can lead to moisture damage over time. Repairing foundation leaks and cracks costs between $2,500 and $5,000 for major repairs and $500 or more for standard repairs.

Install Gutters and Downspouts

Add gutters and drains to your home for an exterior solution that will guide water away from the house. The cost to install gutters and downspouts is $4 to $8 per linear foot. To ensure proper installation, always consult a qualified, licensed individual.

Landscape Grading

Landscaping grading and resloping costs $125 per cubic yard of dirt, with costs rising to $1,600 based on labor and the difficulty of access to the backyard with large equipment. Standing water will weaken your home's foundation over time. Removing standing water can be done by adding a slope to your lawn. If your area has a high water table, then it's best to get your yard sloped before the water has a chance to pool up.

Parging Basement Walls

The average cost to parge a foundation and basement walls is $3 to $6 per square foot depending on the amount of surface preparation needed and mesh required. However, a parge on the basement walls is unproductive unless you have already solved the root cause of your water issues.

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Cost of Basement Waterproofing Systems

Basement waterproofing systems such as B-Dry or Permaseal typically cost from $2,000 to $5,000 on average. A full-perimeter drain tile installation from US Waterproofing ranges from $8,000 to $15,000. A Waterguard basement system costs about $6,000 to install an advanced interior drainage channel.

B-Dry Basement Waterproofing Cost

A professional installation of the B-Dry Basement Waterproofing system costs about $5,000. If you're experienced with the B-Dry system, installing it yourself costs as little as $2,000. The B-Dry basement system is a waterproofing process invented in 1958 that comes with a lifetime warranty. It combines the technology of Rigid Sealer® and subfloor pressure relief drainage.

Permaseal Cost

Permaseal prices for smaller projects are $2,000 to $5,000 on average. Costs may vary depending on the severity of your waterproofing needs. Permaseal says they use the most advanced solutions out on the market that has been developed based on their clients' needs. However, check their BBB reviews before calling for an estimate.

US Waterproofing Cost

For US Waterproofing to install an interior drain tile system, costs range from $2,000 to $10,000 on average. For sealing a foundation or wall cracks, prices start at just a few hundred dollars. Pricing depends on the length of the system and any added components such as a sump pump.

US Waterproofing vs. Permaseal

US Waterproofing and Permaseal are two companies that offer competitive basement waterproofing services that start at $2,000.

US Waterproofing specializes in basement waterproofing and foundation repair in Northern Illinois, Southeast Wisconsin, and Northwest Indiana. Permaseal has operated out of Illinois and Indiana since 1979. They not only address basement waterproofing and foundation issues, but handle plumbing, yard drainage, and concrete lifting and leveling. Many of their smaller projects cost in the $5,000 range.

Waterguard System Cost

The Waterguard basement waterproofing system is designed to be an advanced interior drainage channel, and installation costs up to $6,000. French drains are installed on the outside the foundation, but Waterguard drains are put in along the perimeter of the basement. A sump pump is usually installed with it, so that the price will be the drainage system plus the cost of the pump.

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Causes of a Wet or Damp Basement

Moisture is the main culprit of a wet or damp basement, and it originates from:

  1. Condensation
  2. Surface water or runoff
  3. Groundwater swelling
  4. No window wells
  5. Floor cracks
  6. Vulnerable cover joints
  7. Leaky pipes
  8. Sewage backup

Condensation

Humid weather outside and cold concrete walls, or cold air outside and full heat on the inside, creates a perfect environment for condensation and moisture.

  • Dehumidifier – A dehumidifier could be a solution to this. These work best in airtight basements that do not have humid weather seeping in, so be sure to seal up any air or duct leaks. Dehumidifiers range from small $30 ones meant for crawl spaces to $250 for a bathroom dehumidifier to $2,820 for large basements.
  • Air vents and fans – Make sure air vents are open and clear of debris. Circulate the air well with fans. Vent bathroom air outside and add $50 – $100 to the cost if water pipes need to be installed. A bathroom fan will cost $330 – $900 installed.
  • Insulation – Insulate the drywall and pipes. Insulate the drywall with closed-cell foam insulation which costs $32 – $80.50/SF per inch of thickness sprayed in. Tube pipe foam insulation costs $1.50 – $3.70 per six-foot piece, ranging from ½” – 1” in thickness.

Runoff

Runoff is any water around your basement that isn’t soaked into the ground. To see if any runoff water is making its way into your basement, tape foil over any damp areas and check it after 24 hours. If there are droplets formed on top of the foil, then it's condensation. If moisture is under the foil, then water is coming in from an outside source. Fix runoff problems with:

  • Drain tiles and a sump pump – A drainage system can cost $2,500 to $15,000 to install. A 24” wide trench has to be dug around the foundation filled by putting down gravel, a drain, tiles, and a basin. Then it’s hooked up to the sump pump. The more runoff you get, the wider the drainage pipes have to be.
  • Gutters and downspouts – Gutters that divert water away from the home are an easy solution to runoff water. A home needing 150 – 200 feet of gutters will cost $600 to $1,600 installed or $3 – $8 per linear foot, depending on the gutter material. Make sure the downspouts direct the water away from the foundation by at least ten feet. If gutters are already installed, it’s possible they are clogged with debris.
  • Sloping – You could get your yard graded, with the soil gradually sloping away from the foundation and dropping by 2 – 3” every ten feet, to help send water away from your basement. Resloping starts at $125 per cubic yard of dirt, with costs rising to $1,600 based on labor and the difficulty of access to the backyard with large equipment.

Groundwater Swelling

When the soil cannot hold any more water, it starts to swell and can no longer drain, so the overflow starts flooding into your basement. Swelling might be so bad that you can even watch as the water trickles in. You can prevent this from happening in the future using the methods mentioned above—install a drainage system, install gutters, and grade the dirt around the basement.

Window Wells

Window wells will prevent moisture damage to basement windows that are below or at ground level. The window wells keep soil from pushing in on openings in the foundation while guiding water away from the home. It's best to buy a cover that's included with the model you like—it can range in price from $20 to $85 and go as high as $2,320.

Floor Cracks

Cracks in the flooring pose as a structurally compromised area and have the potential to leak water in. When the soil is full of water and cannot hold anymore, the water will start to pool up and drain through these compromised locations. As mentioned above, an epoxy injection costs about $27 to fill a crack up to ¾” wide in cement. A professional can fill a few cracks for a minimum charge of $150. Larger cracks can cost about $300 to repair.

Cove Joint Repair Cost

The average cost to repair a cove joint is $200 to $300. The home's cove joint is vulnerable to leaks because it's where the basement walls meet the floors. There is a small gap between the two that heavy rain and water seeps in. Interior or exterior drain tiles and an exterior waterproofing membrane are the best fixes.

Leaking Pipes

A leaky pipe is probably the easiest water-related problem to fix; however, a lot of digging might still be required to find the course of the leak. A professional plumber will charge about $500 – $800 if no digging is involved. Usually, just a section of the pipe needs to be replaced, or there is simply a loose valve.

Sewer Backup

Imagine a basement with sewage backup full of contaminants and smells. The cleanup for this should never be done yourself, and only by a professional. A 4-hour job will cost about $1,020, and a full 8-hour day of work will cost $1,750.

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Frequently Asked Questions

Is Basement Waterproofing covered by insurance?

Basement waterproofing services are not covered by homeowners insurance. Typical exclusions from policies are flooding and water seepage that may occur. Flood insurance only protects the above-ground parts of your home from flood damage, and numerous conditions need to apply before any coverage happens.

How Much Does Waterproofing Inspection Cost?

The national average of a waterproofing inspection costs between $350 and $450 depending on your location and the extent of the inspection.

Can You Seal a Basement from the Inside?

Patches can be made, and cracks can be sealed, but these are only temporary solutions. Sealants eventually become weakened if the water is pushing in from the outside.

What Is the Best Basement Waterproofing Method?

An interior drain system is the best lower-cost solution for keeping your basement dry. It only takes a day or two to install, and it’s more affordable than an exterior drainage system. However, the best method is to install a drain tile system with a sump pump hooked up to it around the exterior of the foundation.

Is Waterproofing a Basement Worth It?

Yes. If the basement gets consistently wet, then the foundation is compromised. Waterproofing protects your existing investment and keeps off the cost of having to deal with flooding, seepage, mold, and mildew. However, home improvement waterproofing projects are best left to professionals.

Get free estimates on HomeGuide from trusted basement waterproofing contractors. Cost estimates can include interior and exterior basement sealing, crawlspaces, foundation, or cellar sealing and tanking.

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