Choosing a Drainage Board for Foundations

Choosing a Drainage Board for Foundations

Match the drainage board, filter layer and outlet arrangement to the needs of a below-ground wall.

CHIHAI Material Guides

The HDPE dimpled drainage board in our product catalog is intended for underground garage roof decks. Vertical wall drainage requires a separately specified product and assembly.

The Short Answer

A foundation drainage board should be selected as part of a complete wall assembly. Review the water route, loading conditions, filter layer and compatibility with the waterproofing system.

What the Drainage Board Contributes

A profiled drainage board creates a void that can support water movement alongside a structure. Its shape and material properties help define that space, but the surrounding layers and installation details determine how it works within the project.

Do not choose a board from appearance alone. Confirm the intended application, profile dimensions, relevant compression data and drainage performance under the specified test conditions. The installed assembly also needs continuity at overlaps and transitions.

Illustrative application of a drainage board beside a concrete foundation wall.
Illustrative application of a drainage board beside a concrete foundation wall.

How the Layers Work Together

A below-ground wall may combine waterproofing, a drainage board, filter material and a collection drain. The drainage layer does not replace waterproofing, and water needs a defined route to the outlet.

Conceptual wall assembly with waterproofing, drainage board, filter geotextile and collection pipe
  1. Structure Concrete wall or below-ground structure.
  2. Waterproofing Geomembrane or another specified waterproofing layer.
  3. Drainage A profiled board provides a route for water movement.
  4. Filtration A compatible geotextile limits soil migration into the drainage layer.
  5. Collection route A drain collects water and conveys it to an approved outlet.

Illustrative assembly. Final design is project-specific.

What to Confirm Before Selection

Ground and water conditions

Identify soil characteristics, groundwater conditions and expected water entry.

Loading and drainage capacity

Review product performance under the loading and test conditions relevant to the design.

Connections and protection

Check board joints, edges, penetrations and compatibility with the waterproofing.

Collection and discharge

Confirm how the wall drainage connects to the drain and approved outlet.

Common Questions

Can the board replace waterproofing?

No. Drainage and waterproofing have different functions and should be specified separately.

Which side of the board faces the wall?

Follow the selected product’s installation instructions and the project detail. Orientation depends on the system.

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