Basement walls are constantly battling water, whether it’s groundwater threatening to come up from underneath, moisture in the soil around it, or rainwater falling and pooling against the concrete. As a homeowner you may often hear people say - with basements that water intrusion is inevitable, it’s just a matter of when and where it will occur.
Thankfully, there are numerous basement waterproofing systems that can permanently fix water intrusion issues. Some are pricier than others, but in the long run, preventative measures like proper soil grading tend to cost less than reactive fixes like installing an interior drainage system.
In this guide:
- Common causes of water intrusion
- Effective basement waterproofing methods
- Cost estimates for different waterproofing strategies
- How to fix your leaky basement permanently
- How to save money on basement waterproofing
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Where Is The Issue Coming From?
Finding a permanent solution that will keep your basement dry ultimately comes down to one thing: the underlying problem. Moisture could be a problem in your crawlspace or basement for a variety of reasons. Once you know the source, a professional can implement the proper fix. Below are some of the most common causes of water issues in your basement.
Improperly Installed Downpipes and Gutters
Rainwater can be a big problem for your home’s foundation walls. If you have gutters and downspouts on your home but are still running into flooding or leaky foundation walls during rainfall, they may be installed improperly. Gutters should span any area where soffits are installed, and they should direct water toward downpipes and away from your home.
You may be surprised to find out that what you do in your basement can lead to moisture problems. Many homeowners use rooms in their basement as home gym space, and heavy exhalation and perspiration during exercise can cause moisture build-up in your basement, especially on drywall or other porous material. Cooking or showering in the basement are also common causes of moisture problems.
Leaky Water Pipes
Domestic and heating lines often run through basements or just above basement ceilings, and any leaks in your plumbing can drip into your basement, creating moisture issues. Leaky water pipes could cause massive damage and mildew formation if left untreated. Find a contractor to waterproof your basement
Cracks in Your Foundation
All foundations naturally crack during settling, especially in the first few years following construction. However, any crack in your concrete block wall or basement floor can lead to water intrusion. While cracks that are larger than ⅛” are particularly at risk, even hairline cracks can allow water to seep through.
Improperly Graded Slopes
Even if you have gutters and downspouts installed properly, water from rainfall, melting snow, or flooding can present problems for your foundation wall. If water isn’t naturally guided away from your home, it can and will find its way through cracks or pores in your cement foundation. Water intrusion through concrete could be in the form of liquid water or water vapor.
Groundwater is the water naturally found in the soil below the water table. Depending on how deep the water table is in your area, it could be a significant cause for basement leaks. Homes located in flood zones or close to the coast experience the biggest problems with groundwater, but it can affect homes in any location.
The last major cause for leaky basement walls is the presence of window wells. These wells naturally collect water and pool them against your foundation, which very quickly leads to water intrusion. Window wells should be adequately drained, but soil, plant growth, or fallen leaves can all clog your window well drains and present a problem.
Keeping water away from your foundation wall altogether is the first line of defense and the best way to limit water intrusion. However, even with properly graded soil and functioning gutters and downspouts, some amount of water will come in contact with your concrete block walls and slab.
The second line of defense is exterior sealing, which is an epoxy or other waterproofing product applied to the outside of your foundation walls. Below, I’m going to discuss the average cost involved with applying the common exterior waterproofing materials.
Cost of Waterproofing vs. Damp Proofing
Waterproofing involves the application of a impervious material, often applied as a spray-on sealant. This kind of protection is more thorough than dampproofing, as it protects against soil moisture as well as rainwater.
Dampproofing, on the other hand, is a less protective coating and will only adequately protect your basement from moisture in the soil.
Waterproofing the exterior of your foundation walls typically costs between $5 and $10 per square foot. For an average foundation on a 1,000 square foot home, you can expect to pay about $10,000 for excavating and waterproofing.
Dampproofing is much less expensive at around $3-5 per square foot. For the same foundation as in the above example, the total cost would be about $5,000.
Cost of Cement Waterproofing
Cement waterproofing involves adding a layer of cementitious solution to your exterior foundation walls. The mixture is often applied with rollers, and it creates a waterproof barrier around your cement walls.
The national average price of cement waterproofing is around $1,250, with prices moving up toward $2,000 depending on the footprint of your foundation and the height of your basement walls.
If excavation is required, you should expect to add about $150-200 per linear foot that needs to be excavated. You can expect an average all-in cost for this solution to be around $3,500-4,000.
This option is relatively affordable. However, the ongoing cost of this solution is often higher because any movement or settling in your foundation will lead to cracks in the cementitious solution, thereby leaving your foundation walls open to leaking.
Cost of Foundation Waterproofing Membrane
An impervious membrane is one of the most permanent waterproofing solutions to leaking basements, as it consists of a thick rubber layer and a waterproof polyethylene layer. It’s installed as a sheet between your foundation walls and the soil around it, and it creates a very durable and permanent seal around your cement walls.
Given the difficulty of installing these membranes, you can expect a heftier price tag of around $15,000 for an average foundation. This cost can increase up to about $25,000 for more substantial homes, and you’ll also spend closer to $20,000 if significant excavation is needed due to driveways, patios, or decking.
Cost of Weeping Tiles
Often referred to as French drains or perimeter drains, weeping tiles consist of pipes installed below the soil and up against your foundation. They collect excess rainwater or groundwater and route it to an area that doesn’t pose a threat to your foundation walls. These systems are highly effective, but they do require a bit of excavation to install correctly.
Including removing and replacing the soil for installation, you can expect to pay around $20-30 per linear foot. A French drain for an average, 1,000 square foot house would cost between $5,000 and $7,500. Your cost could be over $10,000 for the same size if excavation is more involved due to landscaping features.
The third line of defense when it comes to sealing your basement is interior basement waterproofing. Because basement water problems are so prevalent and can be severe, many homeowners seal the exterior of their foundation walls and the interior.
Below are some of the most common sealants used for the interior of your basement, along with average pricing for each.
Cost of Concrete Waterproofing and Foundation Coatings
Concrete waterproofing on the interior of your foundation is similar to the cement waterproofing done on the exterior. It involves a cementitious coating applied to the concrete block walls, and it acts as a waterproof barrier, blocking water seepage into your basement.
Concrete waterproofing on your basement’s interior is significantly cheaper than on the outside, as there is no excavation needed. You can expect to pay around $750 on average and up to approximately $1,000 for the application. The cost could go up if your basement is finished, as additional work would be needed to access the cement walls.
In addition to concrete waterproofing, many homeowners choose to have a waterproof foundation coating applied for added protection. This coating is usually an epoxy sealant that costs around $5 per square foot on average. The cost can be as high as $12 per square foot if demo is needed beforehand or if a more expensive coating, like polyurethane, is applied.
Cost of Silicate Concrete Sealers
Silicate concrete sealers are solutions that soak into the top layer of concrete and bind with it on a molecular level, making them relatively effective at stopping water seepage. They appear entirely clear, so the aesthetic of your basement won’t be changed at all.
Silicate concrete sealers are relatively cheap and will cost an average of $5 per square foot for application by a waterproofing company. The price can range from $3 up to $10 per square foot depending on the quality of sealant being applied and the demolition needed if your basement is finished prior to application.
Cost of Waterproofing Paint
Waterproof paint will be most similar in appearance and application to standard interior paint. It gets applied most often with rollers, and it’s an acrylic paint that binds with your concrete to create a waterproof seal.
A DIY waterproofing project for a basement under a 1,000 square foot home will likely cost between $750 and $1,000 for materials alone. A waterproofing contractor will often use professional-grade acrylic paint that costs significantly more and has higher durability. If you hire a contractor to do the application, you can expect to pay around $5,500 for the same size basement. Professionals may offer a warranty on the application, making the extra cost worth it.
Cost of Crawl Space Vapor Barriers
Crawl space vapor barriers are plastic sheets that are installed against crawl space walls. They aren’t waterproof, but they do help prevent water vapor from creating moisture issues under your home. They aren’t very aesthetically pleasing, so they’re often not installed in basements.
A crawl space vapor barrier should be installed by a professional, as quite a bit can go wrong with the process. The installation will cost around $2,000 on average, but prices range from $1,500 to $3,000 depending on the size of your foundation, difficulty in reaching certain portions of your crawlspace, and the height of your foundation walls.
What Are Permanent Fixes For Waterproofing Your Basement?
Because water intrusion is often a recurring problem, it's recommended that homeowners forego cheaper, temporary solutions and begin instead with a permanent fix. Below are the most common and effective ways to waterproof your basement permanently and avoid ongoing repair and water problems.
If you have minor moisture issues in your basement, dehumidifiers are an excellent permanent solution. They won’t fix active leaking, but they will help reduce water vapor in your basement, which in turn can stop mold growth and potential water damage.
Installing Downpipes and Gutters
You can’t avoid rainwater from reaching your foundation, but you can limit the amount of water that does interact with your cement block walls. You can redirect the majority of rainwater away from your foundation by installing gutters and downspouts. This kind of drainage system can collect rain and re-route it to an area of your yard that won’t create a problem with your foundation.
Installing Window Well Drains
If your window wells don’t have drains, one of the best solutions for interior basement water problems is to install them. All window wells need proper drainage so as not to trap water against your foundation. Once they are installed, make sure to clean them regularly, as they can become clogged by plant growth, leaves, or other lawn debris.
Properly Grading Your House
The soil around your house should be graded away from your foundation to direct runoff away naturally. The standard effective grading is a slope of ½” inch for every lateral foot for a total of about 10 feet. This slope will wick water that does fall near your foundation walls safely into your yard rather than your basement.
Foundation Crack Repair
A common point of water intrusion in many foundations is through cracks. All foundations crack during settling, but even hairline cracks can allow water or water vapor into your basement. Foundation cracks should be assessed by a professional, and once they stop growing or expanding, they should be adequately treated with a waterproof sealant or epoxy to prevent water seepage.
How To Save Money Waterproofing Your Basement?
Waterproofing your basement is often a pricey endeavor. Depending on how much work needs to be done in and around your home, it may cost upward of $25,000. There are some things you can do to bring the cost of waterproofing down significantly, though.
As with all foundation repair, getting the job done correctly and permanently the first time around may cost more upfront, but it will save you money in the long run. Temporary solutions are just that: temporary. They may solve your water intrusion issues for some time, but they will fail, causing you to lay out more money to fix the problem. It's strongly recommended you get a permanent solution in place the first time to save money on ongoing home improvement.
One of the best ways to save money when solving your wet basement problems is to treat the problem and not the symptoms. Begin by grading your soil, installing gutters and downspouts, and clearing your window well drains. These simple fixes could correct the issue entirely and help avoid the need for reactive systems like sump pumps, so start with the cheapest options before you lay out thousands for additional work.
Check out this video to find out how to waterproof your basement: