Short answer
Dimple board is a high-density polyethylene drainage and protection membrane with raised studs that create an air gap between soil and foundation wall. Water travels down that gap to footer drainage instead of pressing through concrete. It is a hydraulic break and protection plane—not a standalone product that seals the house without drainage.
Dive deep
Concrete is porous. Wet soil pressed directly against a stem wall drives moisture inward by capillary action and hydrostatic pressure, producing efflorescence, damp walls, and long-term degradation. Liquid coatings on the exterior or interior face can delaminate when pressure builds at the bond line; they are not a substitute for relieving water.
Dimple board—products such as Delta-MS—mounts with studs facing the wall, forming a permanent low-pressure channel. Groundwater hitting the membrane falls to the footing rather than forcing through the wall matrix. On exterior applications, board also protects waterproofing membranes from backfill damage. On interior crawlspace applications, it integrates with perimeter French drain and sump systems so collected water reaches mechanical removal.
Dimple board works as part of a layered system: drainage mat plus perimeter tile, sump, discharge, and where appropriate elastomeric or other membrane layers. It does not replace active pumping or correct grading. It is not encapsulation—it moves water to a designed path rather than trapping moisture against structure behind plastic liners.
Board orientation, termination at the footing, and tie-in to filter fabric and tile determine whether the gap actually drains—or holds water against the wall.
When it applies
- Exterior excavation where membrane protection and pressure relief are required during backfill
- Interior crawlspace stem walls with chronic dampness and integration to perimeter drain tile
- Capillary moisture and efflorescence where hydrostatic relief must pair with a protection plane
- Multi-layer exterior systems where liquid membrane needs mechanical protection from soil contact
When it does not
- Standalone “stick it on and call it waterproof” installs with no footer drain, sump, or discharge
- Substituting dimple board for fixing roof runoff dumping against the foundation
- Encapsulation-style interior liners marketed as complete crawlspace cures without source drainage
- Claims that any single membrane stops hydrostatic pressure without a path of least resistance to tile and pump
We start with a technical site evaluation—moisture sources, soil behavior, crack pattern, and load direction—before specifying drainage, pumping, or structural scope matched to your property.
What we do next
We specify dimple board as part of engineered drainage—paired with tile, sump, and discharge—not as an isolated barrier. Learn about basement waterproofing and drainage integration for a complete protection plane.
