Home Fix: Dwight Barnett answers home-improvement questions. This week's topic is on cleaning a contaminated crawl space or basement.
Q: I have an older home with a bothersome smell. After maneuvering into the dirt crawl space under the house, a broken pipe was discovered. It had probably been leaking sewage for one or two months. We had the pipe repaired thinking this would solve the smell problem. It did not. We discovered that thick plastic had been laid on top of a muddy composting mess.
My husband removed the plastic and dug out several inches of sewage/mud. He also laid oyster shells on top of the damp ground to help neutralize the smell. He then opened all foundation vents and placed a fan to blow the air out from under the house. So long as the fan is blowing, the smell does not drift up through the wood floor and stink up the house.
You have suggested charcoal. Should we put open bags of charcoal on top of the dirt/mud under the house? What else can we do?
A: Raw sewage in a cellar, basement or crawl space can be a serious health concern for the occupants of the home. According to an article published by americanrivers.org:
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“The most common pathogens in sewage are bacteria, parasites and viruses. They cause a wide variety of acute illnesses including diarrhea and infections. These illnesses can be violent and unpleasant, but mostly pass after several days or weeks with no lasting effects. In some cases, however, pathogens can cause serious long-term illnesses or even death.”
The sewage and contaminated soils under the home should be removed by professionals who have the experience and proper equipment to work in such hazardous conditions.
Once the area has been decontaminated, a layer of 6-mil plastic vapor barrier can be installed.
If you are a determined DIYer, though, make sure you wear a long-sleeved shirt, rubber gloves, eye protection and a half-facemask respirator.
Use a sled or piece of plywood as a skid with a rope attached so that a helper can pull the buckets of soil out and a second rope attached so that you can retrieve the empty buckets without having to go in and out with each load.
Once the area has been cleaned, spread hydrated lime to reduce the odors and to dry the soils. Cover the entire dirt floor with a 6-mil vapor barrier. Discard the rubber gloves, clean your tools with a mild bleach-and-water solution and launder your work clothes immediately.
In a basement, use a wet/dry vacuum to clean the spill, emptying the canister into a toilet. Any contaminated material including carpeting and wall coverings should be discarded. Place smaller items in plastic garbage bags and set outside for proper disposal.
Woodwork and wood furniture can be washed using 1 cup household bleach to 1 gallon of warm water. Venting the basement using fans will help to remove odors and speed the drying process.
Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home-improvement questions at C. Dwight Barnett, Evansville Courier & Press, P.O. Box 268, Evansville, Ind. 47702 or email him at d.Barnett@insightbb.com.