Can I Waterproof the Basement Exterior Wall When it is Freezing?

The Temperature Outside

• Rubber-based waterproofing products are available for applying to foundations when the temperature is below freezing, but even these cold-application products have a minimum application temperature, often 10 to 20 degrees Fahrenheit. Applied by brushing, spraying or rolling, the trick to easy application is to store the unopened cans of sealant at room temperature or in the cab of a heated truck and take one can out at a time when you’re ready to use it. If you’re spraying the foundation, use insulated hoses to retain heat.

Exterior Injection

• If your existing basement walls are leaking, it’s best to wait until warm weather to excavate around the house and seal the masonry. Sometimes, waiting isn’t feasible, such as when the waterproofing is required for the sale of the home. Bentonite injection contractors use slurry made from sodium bentonite and inject it between the exterior wall and the soil. The slurry spreads out and forms a solid surface, which helps reduce water leaks into the basement. This isn't a do-it-yourself project. Licensed professionals must apply bentonite injections to reduce the risk of lateral pressure and cracking of the basement walls.

Heating Considerations

• Foundation contractors use all sorts of tricks to warm up cans of cold foundation sealant, but not all of them are safe. Don’t place a can of sealant in front of a job site blower/heater, unless the can specifies that the product is nonflammable. Some contractors “tent” the trench around the basement and use job site heaters to raise the temperature during foundation waterproofing. This can be beneficial for applying nonflammable sealant, but ventilation is necessary to keep kerosene exhaust fumes from collecting in the trench. Follow all safety measures listed on job site heaters.

Additional Foundation Precautions

• Perimeter foundation drains supplement basement waterproofing. In many communities, building codes require the installation of a foundation drain, which consists of a semirigid perforated pipe that sits on the top of the footing and drains into a sump bucket. For the integrity of the foundation and the basement, the best practice is to direct all water away from the foundation walls by installing guttering and downspouts on roof overhangs. Grading the yard to slope away from the foundation at a 2 percent slope is also beneficial.