Foundation Drainage
 Foundation drainage is used in Residential Foundations, consisting of two separate procedures:
- Perimeter draintile properly placed on the OUTSIDE of the wall, next to and no higher than the top of the footing.
- Installation of an exterior drainage insulation board.
As we know, Minnesota was a masonry block basement market for many years. An important part of the Waterproofing System was the draintile placed next to the footing, beneath the floor. This draintile drained water from the hollow cores of the block and therefore was a part of the water control system.
With modern codes, these cores are often filled with grout and will not carry water, making them useless. The primary function of draintile is to relieve hydrostatic pressure on the exterior of the wall; this will not happen if the draintile is placed on the inside, below the floor.
Exterior draintile should be socked or filtered 4” plastic and installed next to and no higher than the top of the footing. There should be 6” to 8” of rock placed on top of the draintile and up the wall. The rock bed should be covered with a filter fabric. If draining insulation were used on the exterior wall, a poly film cut off sheet would be placed over the rock bed rather than a filter fabric.
High Performance Waterproofing Systems
Through our years of experience we have found the best performing steps of all drainage systems to be the following: Subfill below slab with 4” to 6” of washed rock, sleeve the footings from inside to outside every 6’ to 8’. Connect to interior radon sump basin and, if possible tie to a drainage Waterproofing System which will assure a dry, usable basement.
Please call us at 763-780-5926 or email us: info@waterproofinginc.com to learn more about how Waterproofing Inc. helps builders succeed.
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