Monday, December 12th, 2011 by Jacques Bouchard
There are three main approaches to drying a basement: exterior waterproofing, negative-side sealing, and interior drainage. What follows is a clear-cut evaluation of the advantages and disadvantages of each:
Exterior waterproofing on an already built home requires some excavation to expose the foundation. This involves digging up anything around the edges of the home, including gardens, shrubberies, sidewalks, and more. The excavated dirt will be mounded in the yard, usually on tarps, until it can be returned. If there is a failed exterior system in place, that will be removed during the excavation process.
Next, a drain pipe will be laid around the foundation exterior, with an extending pipe sloping down and away from the foundation. A waterproof coating will be applied to the outside of the foundation walls – ideally, after they've been cleaned free of debris. Then, removed soil is backfilled into the excavated space, and an attempt to restore the landscaping may be conducted. A year after the soil is backfilled, it will settle and need regrading.
Advantages: Many contractors swear by this method of waterproofing, pointing out that water and humidity are kept from the space with this method (as moisture will pass through the pores of concrete and into your basement). This method works quite well for many homeowners, and has been used for many years.
Disadvantages: Exterior waterproofing is time-consuming, expensive, and destructive to landscaping. The excavation process is disruptive to the home and neighborhood, requiring heavy machinery and dirt to be piled on your lawn. Additionally, it costs about twice the amount of interior waterproofing.
One popular do-it-yourself solution (you won't see many contractors suggesting this method) is to coat the interior walls with a waterproof paint, dampproof coating, or hydraulic cement. These coatings are available at local box stores.
Advantages: This is a fast installation, and it's simple enough for even a novice do-it-yourselfer to undertake. Among the options listed, it's by far the least expensive, and it can be done without jackhammering, excavation, dust, or the installation of a drainage system.
Disadvantages: If negative-side sealants worked, you can be sure that contractors would give up on the other, more complicated solutions and adopt this solution. However, it's been proven time and again that these coatings will generally peel, chip, or flake off the walls in a few year's time – and they're not effective at stopping leaking through cracks in the walls and floors. Once applied, these products are extremely difficult to remove, and you'll find that the basement is worse off than before.
This solution requires the interior perimeter of the basement floor to be removed – typically with a jackhammer. Once the floor has been removed, a trench is created, and a bed of drainage gravel is placed. A drainage system is put into place, directing the water to a sump pump system, and then the floor is restored.
Advantages: This solution can be installed quickly – usually in about two days – and can be done at about half the price of the exterior methods. Interior systems are reliable, and can be effectively serviced if something goes wrong, with no need to excavate the exterior to access the drain. Because this system actively pumps water from the basement, it is much more effective at water removal than a passive drain placed outside the home.
Disadvantages: There's a lot of competition in the marketplace for products used for interior drainage systems, as well as sump pumps. Some are reliable, some are not, and it can be difficult to differentiate between the two unless you're a professional in the marketplace. When jackhammering is required, dust will be created, some of which can find its way into the home. For homes with monolithic foundations and very thick floors, we recommend minimizing the potential for dust by installing a drain system located along the baseboard instead of under the floor.
Contact CleanSpace® of the Carolinas today for more information about the Basement Systems patented and award-winning waterproofing systems that are backed by a lifetime limited warranty! We offer a free estimate for basement waterproofing in North Carolina and South Carolina.