Most new homes are built with a properly graded lot and waterproofed basement, but you may have to address this if you’re moving into an old house. While there are many ways to waterproof your basement, the best option depends on what’s happening in and around your home’s exterior. We’ve compared interior and exterior waterproofing methods to help best resolve your moisture issues and keep your home structurally sound.
Method 1: Sealants and Epoxy Injections
Protect your basement from moisture using a sealer on the walls and epoxy injections to fix cracks and gaps. The waterproof coating prevents the surface from getting damp and developing mold or mildew. Sealing basement walls may also be an easy do-it-yourself (DIY) job because the product is just sprayed or rolled on the surface and left to dry. It’s similar to painting walls, but you must first remove any existing mold or mildew before applying.
Standard acrylic sealant is a cost-effective solution at $1 to $8 per square foot.* However, there are some restrictions. While sealants can be applied to concrete walls, they can’t be used over painted drywall. You’ll need to consider alternate solutions if your basement is fully or partially finished. If your concrete walls are painted, you may need to strip the paint off first.
Another interior waterproofing method is epoxy injections to fix cracks and leaks in the basement floor and walls. Epoxy is extremely durable in any setting and easy to apply. It costs $800 to $1,500 and can be outsourced to a professional or done as a simple homeowner DIY.
Benefits and Drawbacks
Using sealants and epoxy is a straightforward, inexpensive project, but it comes with some disadvantages. See an overview below.
➕ Simple project to DIY or hire out
➖ Doesn’t fix the root cause of a wet basement
➖ Only lasts about 10 years
Method 2: Interior Drainage Systems
Installing an interior drainage system helps resolve water issues without damaging your landscaping. Sump pumps achieve this by pumping out standing water and directing it away from the basement. There are two types of sump pumps: submersible and pedestal. A submersible installation is more difficult because it requires digging a hole into the concrete floor. For an easier installation, opt for a pedestal sump pump, which sits atop the basement floor, instead of being submerged underneath it.
No matter which sump pump you choose, maximize its effectiveness by installing interior drain tiles. This waterproofing product reduces hydrostatic pressure caused by groundwater and protects your basement walls and foundation from weakening under such intense pressure.
Sump pump installation costs $1,275 on average. Adding a drain tile system costs between $4,000 and $12,000.
Benefits and Drawbacks
Interior drainage systems waterproof your basement without ruining your yard, but they’re costlier than epoxy and sealant. Here are some other pros and cons:
➕ Addresses rising groundwater issues
➕ Leaves exterior landscaping intact
➖ Doesn’t address how water gets into basement
➖ Not easy to do in a finished basement
Method 3: Exterior Waterproofing
Consider exterior waterproofing to fully protect your basement and foundation walls from water damage and musty smells. Get gutters and downspouts installed if your home doesn’t already have them. Together, they divert rainwater away from your foundation without damaging your yard. Gutter and downspout installation averages $1,900 for an average-size home.
Another effective basement waterproofing system is installing a French drain in your yard. A contractor will dig a trench on a downward slope in problematic areas of your yard and place a perforated pipe and gravel inside. This combination directs water away from your home and can also resolve standing water issues in your yard. The average cost of a French drain installation is $9,250.
You can also add exterior drain tiles with a sump pump for $4,000 to $15,000. Put them around your foundation to proactively pump water away from your house. This involves digging a trench around the home’s perimeter and filling it with several layers of washed gravel and filtration fabric. Sealant is also applied along the foundation to prevent water seepage.
French drains and drain tiles are two of the best ways to avoid major water damage under your house, but they also require heavy excavation work in your yard. It’s a larger investment of time and money, but the results are long-lasting.
Benefits and Drawbacks
➕ Doesn’t interfere with a finished basement
➕ Lasts decades with proper maintenance
➕ Prevents water from entering your basement or foundation
➖ Disrupts existing yard and landscaping
➖ Most expensive option
➖ Requires professional installation
*Unless otherwise indicated, all cost data in this article is from Angi and HomeGuide.
What Is the Best Way to Waterproof a Basement?
Addressing water in your basement should be a priority on your list of home improvement projects. The best waterproofing method depends on your home’s specific issues.
Sealants and epoxy may be best if the following apply:
- Your walls are unfinished, or you need simple window seal repair to keep moisture out.
- You want to eradicate mold and mildew growth in a damp basement.
Consider interior waterproofing if the following apply:
- Rising groundwater is the primary issue causing moisture or standing water.
- There’s not enough excavation space around the exterior perimeter of your home (such as in a townhome or small city lot).
- Your basement is unfinished with concrete floors and walls, making tackling a more invasive waterproofing project easy.
- You want to start with a less costly waterproofing alternative for your basement.
Exterior waterproofing may be best for your project if the following apply:
- You already have a finished basement and don’t want to disrupt interior waterproofing systems.
- You’re ready to invest in waterproofing your basement as fully as possible.
- You want a damp-free basement you can use as living space.
- Water runs toward your basement from the outside.
The best way to achieve a dry basement is to get a professional assessment of the causes leading to moisture under your house. While it’s easy to apply sealant and epoxy on your own, more complex drainage systems should be handled by an experienced professional. Consider getting two or more quotes for a consensus on how the water is currently entering your basement and to get a better idea of local rates.
Basement Waterproofing FAQ
What are the best basement waterproofing products?
The best basement waterproofing products include sealant, epoxy, sump pumps, and dehumidifiers. For more comprehensive waterproofing, consider getting a contractor to install interior or exterior drain tiles, plus gutters and French drains outside. Get the best results by addressing the moisture’s root cause before deciding on a strategy.
How do you completely waterproof a basement?
Completely waterproof a basement by addressing all areas contributing to moisture problems. This includes sealing walls and the foundation and diverting water away from the home using drains and gutters, both inside and out. Be prepared for when water does enter by installing a sump pump that pumps the moisture out of the basement and into the yard.
Is Drylok a bad idea?
Drylok is a bad idea if you only focus on sealing your basement walls without addressing the root cause of your moisture issues. While a sealant can prevent water damage and mildew growth on the protected surfaces, it doesn’t do anything to keep water out of your home. In most cases, a sealant like Drylok should be just one part of a larger plan to avoid moisture issues in the basement.
Should I waterproof my basement from the inside or outside?
You should waterproof your basement from the inside if water still actively enters your home, such as from rising groundwater. You should waterproof your basement from the outside if your moisture issues are due to improper lot grading that directs water toward the house. In some cases, you may need to do both in order to fully address your water issues.