With any foundation coating and insulation you might use to help avoid a wet basement or seeping slab, it must be paired with permanently working drain.
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Perimeter Foundation Drains
Every foundation below grade should be equipped with an exterior perimeter drain. Always work out a drainage plan before digging to locate cleanout and daylight locations of perimeter footing drains (Figure A).
Place drain “tile” — typically 4-in. Schedule-C PVC or ABS pipe — with the holes down on a bed of gravel.
The gravel surrounding the drain should be wrapped with a geotextile, or filter fabric, to keep fine particles from clogging the drain tile.
Place drain tile straight and level, or with a slight pitch toward the exit. Do not attempt to create a pitch when using flexible drain tile, because undulations in the level can cause clogging. Flexible drain pipe should be placed on the footing shelf to prevent dips and sags (Figure C). In either case, perimeter drain pipe should never be above the surface of the slab.
Tile should drain to daylight. If this is not possible, install a sump basket and a sump pump that discharges above ground away from the building (Figure B).
Figure B: Interior Sump Basket
Figure C: Placing Footing Drains
Perimeter drainage can be provided with stay-in-place footing forms, such as Form-A-Drain® — to ensure a level perimeter drain. These systems usually provide a larger capacity than typical foundation pipe systems.