This is a problem that can cause damage to your health and home
Moisture problems in existing basements are common, but often not understood or properly treated. If your basement is unfinished this may not present a great problem.
Finishing a basement prior to dealing with a moisture problem can result in creating health problems or lead to damage to your house as well. This could take form in molds or mildews.
Basement water problems are solvable, but this comes with a cost to have it done right. It is best to contact a professional to evaluate the water issues you may be experiencing.
Understanding The Problem
To correct the problem you must first understand where the water is coming from. There are 3 sources of moisture.
1. Water from rain or ground water.
2. Interior moisture sources such as humidifiers, unvented clothes dyers, bathrooms and cooking, or moisture in concrete after construction.
3. Exterior humid air that enters the basement and condenses on cooler surfaces.
Basement Moisture Sources
In one inch of rain, 1,250 gallons of water falls on the roof of a 2,000 square foot house.
Without proper grading, gutters and downspouts, some of this water flows into the basement. Below grade the water table can also rise due to flooding or seasonal conditions.
Typical Causes of Moisture Problems in Basements
1. Poor or inadequate grading: If the ground level slopes toward the basement the water will be directed in. Solution: The grade around the house needs to be sloped at least one inch per foot for no less than 6 feet from foundation wall.
2. Defective or missing gutters: Without proper drainage from your gutters and downspouts, rainwater can be directed toward the foundation perimeter. Solution: Place a minimum of one downspout per 50 lineal feet of roof eve. Extensions to the downspouts should extend at least four feet from the wall.
3. Window wells: This can be a source of entry for water if improperly built. Water will be directed toward rather than away from the foundation. Solution: Window wells should be filled from the footing to the window sill with 3/4″ coarse aggregate. This will allow the water to disburse properly along with proper slope away from foundation.
The examples above are just a couple of potential problems that may be related to the moisture problem you may be experiencing. Other areas to watch are ineffective drainage systems, and structural cracks in the foundation walls.
It is recommended to remove interior moisture sources, then evaluate the gutters, downspouts and grading around the house. With those items corrected first could take care of the issue easily. If the problem persists then proceed with an interior or exterior drainage system.Keep in mind that all exterior drainage systems must drain to a sump that can be pumped back out. The sump must have an airtight, childproof cover.