September 20th, 2014 8:47 PM by Dan Howard
Moisture and mold: The soil surrounding the pipes and gravel installed under the concrete is always wet. Wet soil will grow mold. The mold spores, odor and evaporating moisture will travel into the house through the opening in the french drain system.
Radon: Radon normally enters homes from small cracks and openings in a concrete floor. A french drain system has a big opening along the entire perimeter of the foundation. This opening allows radon to more readily vent into the home. If you already have a radon system installed, a french drain system can pull combustion gases from your appliances back into a home.
Improper water discharge points: Installers of all types of systems often take the discharge pipe to outside the basement to directly at the foundation edge. This saves installing the extra pipe which would get the water down hill away from the foundation. As a result, the water drains into the wall and then into the drain system. It then gets pumped to the pipe outside the wall and the process starts all over again.
Damaged footers: Most contractor web sites, drawings and proposals will show a pipe system that is installed beside a footer. The worker with the jack hammer has a different perspective. That person needs to haul broken concrete out of the basement and mix and place new concrete. The smaller amount of concrete that is removed from the basement results in less work needed to haul out and replace it. Oopps, the worker often decides to take out the footer.