Advanced Mold Diagnostics, LLC is an environmental consulting company located in Broomall, Pennsylvania.
The Illustration Above Is Typical Of A Block Foundation And Shows Two Different Ways To Install A French Drain Waterproofing System.
Not all situations/foundations are the same, but this is typical for many.
The one on the left shows the collection pipe/tube sitting on the footing and is less expensive because it requires less work, but allows water to come into contact with the floor. The one on the right shows the perforated pipe alongside the footing which keeps the water away from the slab (floor) which will reduce the vapor pressure inside the basement.
NOTE: The crock and the discharge in the illustration are not located where they should be. The crock should be up against the footing and the discharge tight up against the wall. The illustration is designed to show how some systems are improperly installed.
The first thing when installing a French Drain Waterproofing System is to install critical barriers so concrete dust doesn’t escape from the work area (basement/crawl space).
Break open floor with jack hammer 8″ – 18″ from the foundation walls.
Dig a trench alongside the footing if one is present, removing the dirt.
NOTE: It’s Important to remember! Systems that sit on top of the footing cost less to install, but they are ineffective in keeping water away from right below the slab.
Install bed of gravel (clean stone)
Install geo-textile fabric around pipe to prevent clogging.
Install perforated drain pipe. Some companies extol the virtues of ADS (black corrugated pipe) over PVC or the other way around. Some claiming that schedule 40 PVC being stronger is better. They all work, some more appropriate than others depending on the situation.
Install heavy-duty sump crock with gasketed bolt down lid.
Install heavy duty 1/3 – 1/2 hp effluent(able to discharge solids) sump pump along with discharge to outside with check valve in line.
Drill bleeder holes if foundation is block.
Install mirra-drain (dimpled heavy duty plastic) against foundation wall.