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Basement Waterproofing

moisture leakage basement

Moisture problems are prevalent all over North America. They are viewed as one of the single largest factors limiting the useful service life of a building. Wet basements are the most frequent complaint of homeowners. Over 60 percent of basements have moisture leakage and 38 percent experience mold and fungus growth due to an elevated level of moisture.

Finding the cause of the problem is absolutely essential to its cure. Though trying to find the source can be daunting we hope the following ideas and tips will be helpful:

Identify the Source of Moisture

  • If, after a heavy rain, you have standing water in your basement, it’s likely from a leak in the foundation.
  • If you have water stains on the ceiling you most likely have a burst water pipe.
  • If you can’t identify where the moisture is coming from, whether it’s seeping in from the outside or condensing inside, tape a twelve-inch square of aluminum foil to a wall that is prone to dampness, sealing all four sides to make the surface behind the foil airtight. In a day or two, if the side of the foil that was against the wall is wet, the problem is seepage. If the outside is wet, it’s condensation.

Take Preventative Action

  • Lawns that are flat or slope toward your home invite surface water to drain down against the basement walls allowing water to enter through the cracks and pores causing wet spots on the walls. Make sure the ground around your house slopes away from the foundation - about one inch per foot. Extend the slope for at least ten feet. If this isn’t possible then surface drainage should be intercepted and rerouted some distance from the house.
  • Defective, clogged, or nonexistent gutters and downspouts permit rain water to form puddles and wet soil against basement walls. Install gutters and downspouts where needed and keep them clean of debris. Invest a few bucks in a gutter shovel; the best invention since sliced bread and designed to slide along the gutter and scoop away debris. Or, for a maintenance free gutter, install gutter toppers, screening, or a basket-shaped wire strainer over the downspout outlet. To prevent high concentrations of water forming at the point of discharge, use a concrete gutter or splash block to carry the water away at a slope of one inch per foot.
  • If you have a sump pump, make sure it’s working properly.
  • If you find condensation, or sweating, on cool surfaces in the basement such as walls, floors, and water pipes, you should insulate the water pipes.
  • Do NOT close your subarea vents during the winter because you think it will keep your house warmer. The purpose of foundation vents is not to adjust the energy efficiency of your home. It is to prevent humidity caused by ground moisture from condensing on the structure and rotting the wood framing. Open vents are more important in the cold weather than in the summer, however open vents should be maintained at all times regardless of the season.
  • To reduce indoor humidity use ventilation fans in kitchens and baths to control moisture. Make sure the fans are venting directly outside. Make sure your clothes dryer is being vented outside. Check the vent duct and make sure it’s attached securely to the dryer. Clean the vent duct at least once a year.

Steps You Can Take to Prevent Future Moisture Problems

  • Install a sump pump where gravity drainage is impossible or impaired. Sump pumps are used to raise the water to a level where it can be carried off through a drain line.
  • Apply waterproofing compounds to the interior walls. Keep in mind, interior wall treatment will not work if major exterior water conditions still exist.
  • Exterior injection of waterproofing substances into the space between the soil and the basement wall. The substance swells to many times its dry volume when it is put into slurry form. The slurry will tend to penetrate and plug cracks where water might also find a path to the basement interior, thus reducing the flow of water.
  • Excavation. Sometimes it is absolutely necessary to take the extreme measure of exposing the basement walls, treating them, and then re-grading the soil.

A dry basement will protect the investment you made in your home as well as enable you to use the space for additional living or storage space. The following links may be useful in your journey to a healthier and dryer basement:



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