Are you tired of dealing with water in the basement? If so, you’re in good company. Wet basements can be found in houses of all ages, sizes and styles. A wet basement is one of the most troublesome problems a homeowner can face in the home. Water in the basement makes this part of your house unusable as living space. And high levels of moisture in the basement will inevitably cause mold on vulnerable materials like wood, carpeting, paper and gypsum board.   


Fortunately, there are proven ways to solve basement water problems. Years of dealing with water leakage in basements has revealed what works to keep basements dry and what doesn’t. Just ahead, we’ll go over the details you need to know if you want to solve basement water problems. 


What causes a wet basement?

If you have water coming into your basement, you can be fairly certain that there are several factors contributing to this problem. Exterior conditions can play in a role. These include roof runoff that dumps large quantities of water next to the foundation, and ground that slopes toward the foundation rather than away from it. 


The condition of the foundation can contribute to basement water problems. Cracks in a foundation wall provide pathways for water to enter the basement. But it’s important to understand that even a foundation in good condition can admit water, through leaks and seepage. The concrete that’s used to build your foundation –in the form of poured concrete or concrete blocks—will naturally absorb and release moisture. This characteristic explains water seepage through foundation walls in the basement; it’s why your basement walls often feel damp to the touch. 


During wet weather, water in the soil around the foundation puts a great deal of pressure on the foundation. Hydrostatic pressure enables ground water to find the weaknesses in your foundation, leaking into your basement through gaps and cracks. One of the most common leakage areas is the gap between the basement’s concrete floor and foundation walls. This gap exists in most basements, because the masonry walls and floor are built separately. 


Interior vs. exterior waterproofing

Basement waterproofing can be done from outside the foundation, or from inside the foundation. The “damp-proofing” coating applied to a foundation when a house is built cannot be thought of as a waterproofing system. It’s typically an inexpensive coating that can limit seepage through foundation walls but not serve as complete waterproofing protection. In an existing house, you have two basic options for basement waterproofing: 

  • Exterior waterproofing systems are expensive. Coating the exterior of your foundation with a waterproof coating or membrane, and installing a perimeter drainage system (sometimes referred to as French drains or curtain drains) is one way to waterproof a basement. Homeowners rarely choose this waterproofing option because it’s much more expensive than interior waterproofing, and much more disruptive to the property and a home’s inhabitants. Exterior waterproofing requires the use of heavy equipment to remove the soil and large plantings like bushes from around the foundation. Then a foundation sealing treatment is applied, and a drainage system is installed along the base of the foundation wall. Unfortunately, these drain lines can clog with silt over time, rendering them ineffective in reducing water pressure against the foundation. 
  • Interior waterproofing systems are affordable and reliable. Installing an interior drainage system to create a dry basement dry is usually a better option than installing exterior drainage. An interior drainage system can’t be clogged by silt. Most interior waterproofing systems can be installed in just one or two days, with minimal disruption to the household. 


How does a basement waterproofing system work?

An interior waterproofing system functions in a very basic way. A perimeter drainage system –sometimes referred to as French drains—collects water and carries it to a sump pump that automatically pumps the water to the exterior. This system is largely hidden in your basement. The drain lines are installed flush with your basement floor, right where the floor meets your basement wall. These lines converge at a sump pit –a circular hole in the basement floor where a sump pump is installed. The sump pump is equipped with a float valve. Whenever the collected water in the sump pit reaches a preset level, the sump pump turns on automatically, pumping the water outside.


The reliability of this waterproofing system isn’t difficult to understand. An exterior waterproofing system attempts to seal every leak and gap in the foundation, a nearly impossible task that does little to relieve hydrostatic pressure. The interior drain-and-sump system minimizes hydrostatic pressure by providing a drainage system to remove basement moisture. 


Methods to reduce water leakage

Depending on the condition of your basement walls, a basement waterproofing specialist may suggest one or more treatments to reduce leakage through foundation walls. Hydraulic cement can be used for crack repair in foundation walls and floors. Basement walls can be coated with a special concrete paint formulated to reduce leakage. A final method is to install a plastic moisture barrier against the wall. These heavy-duty barriers can be installed in the form of thick vinyl sheet material or rigid plastic panels. They are typically only available from basement waterproofing specialists. The purpose of these barriers is to capture all wall leakage and seepage, and direct this water into the perimeter drain system before it reaches the basement floor.  


Waterproofing a poured concrete foundation

A poured concrete foundation is less likely to have leaks in foundation walls than a concrete block foundation. This rule applies unless there’s foundation damage that includes cracks in foundation walls that allow leaks to develop. If a basement waterproofing inspection reveals cracks or areas of deteriorated concrete, the contractor performing the inspection will suggest repairs to these areas in addition to standard waterproofing treatments. 


Waterproofing a concrete block foundation

Concrete block foundations are more likely to have water leakage, because of all the mortar joints between blocks, and because blocks have hollow cores. If ground water penetrates into block cores, it can permeate into the basement through the thin interior facing of the blocks, or leak inside through cracks in mortar joints. 

What to do before a basement waterproofing inspection and estimate

Basement waterproofing contractors are the most capable contractors to use if you want to waterproof your basement. There are some useful things you can do before calling one of these specialty contractors to get a free basement inspection and a free estimate for basement waterproofing. 


The first thing to do is to make sure your system of gutters and downspouts is working properly. By controlling roof runoff, you’ll be able to lessen the hydrostatic pressure bearing on your foundation. To prepare for basement waterproofing inspection, clean up and organize your basement so that wall and floor areas are accessible, especially in places where leakage is occurring. Hold off on buying a dehumidifier to help take the dampness out of basement air. Basement conditions demand more of a dehumidifier than most standard models can deliver. Your waterproofing contractor will have specific recommendations about models that will perform well. Because this type of dehumidifier will drain directly into the sump pump, you’ll never need to worry about emptying it.


Basement waterproofing costs can vary widely. There are numerous factors that a basement waterproofing contractor will utilize to determine the cost of a basement waterproofing system. The most important factor, in most cases, will be the size of the drainage system that’s required. You can expect to pay more if basement foundation repairs are required, in addition to basement waterproofing.