What is the cost of basement waterproofing?

Basement moisture problems range in severity from damp walls smelling of mildew to standing water on the floor, and they all call for action. Even seemingly insignificant moisture can have health consequences for mold-sensitive residents. More severe water problems can render the basement unusable and even undermine the foundation.

As you would expect, the cost of basement waterproofing balloons when you have to hire pros. You can often avoid that by doing some simple things yourself, like fixing cracks in concrete walls and applying a waterproof coating to prevent seepage. Outside, you can add extenders to your downspouts to direct roof runoff away from the foundation.

Because it’s close to the water table, however, a basement is at the mercy of natural forces that create issues calling for more drastic — and expensive — solutions. You might need a sump pump, an indoor or outdoor perimeter drain, or a waterproof barrier around the foundation. These are typically jobs for pros.

Dallas Nevill of Rainbow Restoration, a Neighborly company, says costs range from $1,900 to $6,000 for a typical house. But these could easily rise considerably depending on the mitigation methods.

Factors That Impact Basement Waterproofing Cost

There’s no standard cost for basement waterproofing. The amount you spend depends on a number of factors, including:

• Size of the basement: Nevill estimates costs ranging from $3.50 to $6.50 per square foot.
• Cause of the water incursion: Water can seep up through the floor when the groundwater level rises, or enter through the walls due to insufficient outdoor drainage. These require different solutions.
• Severity of the problem: It won’t cost as much to patch seeping walls as it will to address full-scale flooding. Water damage repairs to the foundation and mold remediation also must be figured into final costs.
• Finished vs. unfinished basement: Basement waterproofing tends to be more complicated and expensive in a finished basement. Flooding or heavy seepage usually calls for replacement of drywall and possibly flooring.
• DIY vs. professional waterproofing: Homeowners can save a lot by doing their own work, but this isn’t always practical or even possible.

Cost for DIY Basement Waterproofing

The moisture problems homeowners can fix themselves are generally caused by condensation and minor seepage. Tools and materials are the only costs involved in the repairs.

Curing basement condensation

Basement moisture problems don’t always originate outside. Many arise due to poor ventilation and/or a source of humidity in the basement, like a clothes dryer or clothesline.

Homeowners can often mitigate these by moving the source of the moisture to another place, then ventilating and drying out the basement with fans, heaters and dehumidifiers. The cost will vary depending on the size of the basement, but a good dehumidifier for around 1,000 to 1,500 square feet costs between $100 and $200.

Insulating the walls

Sometimes, the fix for condensation is more complicated and expensive. Temperature differential at the walls, which are typically colder than the rest of the basement, are a common cause of condensation. Insulating the walls is a solution, and the cost depends on how you do it.

If you install wall framing and fill it with fiberglass insulation, you’re looking at between $3 and $5 per square foot for materials. Add new drywall and the cost jumps by about $1 per square foot. Then you have the beginnings of a finished basement. On the budget side, you can glue foam insulation board to the walls for about $1 to $2 per square foot of wall space.

Patching and coating the walls

Patching wall cracks with hydraulic cement and applying an elastomeric coating is a DIY-friendly job that provides protection from seepage from outside. You can buy enough hydraulic patching cement for most jobs for around $20, and the coating costs about $2.50 per square foot.

Cost for Pro Basement Waterproofing

Groundwater seeping through the floor or walls and collecting on the floor often requires more than one waterproofing strategy. You often need to hire a pro, and costs are likely to rise considerably higher than the upper limit quoted by Nevill.

Installing a drain tile system

A drain tile system consists of French drains or troughs dug into the basement floor along the walls that direct water to a central runoff point. Installers carefully calibrate the drain slope and cover the drain with tiles. This could cost from $8,000 to $15,000.

Installing a sump pump

A sump pump often goes hand-in-hand with a drain tile system. Installers break through the floor to dig a sump pit, then hook the pump to a drain pipe that goes outside or into the home’s waste system. Installation costs range from $1,500 to $3,000.

Solving outdoor drainage issues

Poor drainage around the foundation causes many drainage moisture issues. Regrading along one wall costs $500 to $1,000, rising to $1,000 to $3,000 for the entire house.

A French drain around the outside perimeter of the house may be a better solution. This is something you can do yourself with a shovel. If you prefer to hire a pro with trenching equipment, expect to pay $10 to $50 per linear foot, depending on depth and soil conditions.

Waterproofing the foundation from outside

Sometimes the best cure for a leaky foundation is installing a waterproof membrane around the outside perimeter. This involves a fair amount of digging and costs from $3 to $6 per square foot for labor and materials.