Materials for drainage, waterproofing and civil engineering
Drainage Board vs. Drainage Sheet vs. Geomembrane
Understand the terminology, compare their functions and choose materials by project requirements.
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
Drainage boards create a path for water movement. Geomembranes act as barrier layers. The term drainage sheet can describe different drainage products, so confirm the structure and function before comparing specifications.
A Quick Comparison
| Feature | Drainage Board | Drainage Sheet | Geomembrane |
|---|---|---|---|
| Typical form | Profiled sheet or panel | Sheet or composite product | Continuous membrane |
| Main role | Water movement | Depends on product structure | Barrier to water flow |
| Confirm before selection | Profile, loading and flow | Core, fabric and intended use | Thickness, surface and joints |
Understand the Terms
01
Drainage Board
A profiled plastic sheet or panel with dimples or channels that creates a void space for water movement.
02
Drainage Sheet
A general term that can refer to various drainage products, such as a dimpled sheet, composite sheet or drainage core, often used with geotextile.
03
Geomembrane
A continuous, low-permeability membrane used as a barrier to water flow.
How the Layers Work Together
A project may need drainage, filtration, protection and waterproofing as separate, coordinated functions.
- Structure Concrete wall or below-ground structure.
- Waterproofing Geomembrane or another specified waterproofing layer.
- Drainage A profiled board provides a route for water movement.
- Filtration A compatible geotextile limits soil migration into the drainage layer.
- 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
Required function and application
Confirm whether you need drainage, waterproofing, filtration or a combination, and the project type.
Loads, water conditions and outlet
Consider soil loads, groundwater conditions and where water will be collected and discharged.
Product dimensions and performance data
Review product structure, material properties and test data relevant to your project.
Joints, protection and installation details
Consider membrane joints, overlaps, protective layers and installation method.
Common Questions
Can a drainage board replace waterproofing?
No. Drainage and waterproofing have different roles.
Is every drainage sheet the same?
No. Confirm the product structure and intended function.
Products
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Related Reading
Continue Reading
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Choosing a Drainage Board for Foundations
Match the drainage board, filter layer and outlet arrangement to the needs of a below-ground wall.
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Roof Garden Drainage Layer Guide
Explore the roles of filtration, drainage, protection and waterproofing beneath a planted roof or landscape deck.
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