For water seeping through walls, either concrete block or poured concrete, the better method is to install a draintile/gravel filter system on the outside of the structure. Installing the system involves digging a trench down to the bottom of the footing. After the wall has been thoroughly scraped, a thick coating (approximately 3/16”) of Elastomeric liquid waterproofing membrane and Miradrain applied with a trowel. It is then covered with a sheet of four mil rubber membrane for an extra layer of protection. A four-inch perforated pipe (draintile) is laid at the proper footing location and covered with at least two feet of clean, washed gravel. The remainder of the trench is backfilled with soil. The gravel filter is protected from intrusion of the soil backfill by an intervening layer of straw. This type of system will effectively intercept any water coming toward the wall.
Inside Draintile System
For seepage water coming through the floor or along the joint between the floor and the wall, the more appropriate waterproofing method is to install the draintile/gravel filter system along the inside foundation footing. Installation of this type of system requires removing the concrete floor for a width of 18 to 24 inches along the wall in the seepage area. After removing the concrete, the trench is dug in the underlying soil materials. A four-inch perforated pipe is then placed adjacent to the footing with Miradrain dewatering mat and the trench is backfilled with clean, washed gravel. Then, the concrete floor is replaced to it’s original grade. Water seepage resulting from excessive hydrostatic pressure beneath the structure can be effectively intercepted and controlled with this system.