Drainage Board

What is a Drainage Board

Definition: What Does the Term Drainage Board Mean?
A foundation waterproofing component, that consists of a sandwiched panel that allows water to flow ( drain ) vertically down the interior of the sandwich panel.

This panel is installed against a foundation, or retaining wall to allow the discharge of any lateral water pressure on the wall. A drainage board is part of a composite system, usually made up of a layer of impervious material that is immediately adhered to the surface of the wall, then the installation of the drainage board which is adhered to the impervious layer. The final layer is a protection layer, that is adhered to the drainage layer, to prevent any rocks that may be in the backfill to harm the drainage layer. The intent of the entire system is to remove the water by allowing it to flow vertically, using gravity, down to the base of the wall, where it is usually picked up by a separate drainage system of piping, sump pumps or drywells.
Drainage layers are also used to cap a landfill, the cap is normally made up of again, an impervious layer of material, not adhered, but installed atop a controlled layer of fill material over the waste of the landfill. A drainage layer is installed on top of the impervious layer, and a protection layer placed on the top of the drainage layer. The difference with a wall waterproofing system, and a landfill cap, is that the landfill cap is made of heavier more durable materials, which are merely laid on the top of one another. The wall systems are normally adhered, first to the wall, and then to each successive layer.