DRAIN BOARDS FOR WATERPROOFING SYSTEMS
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DRAIN BOARDS FOR WATERPROOFING SYSTEMS
What is a Drain Board?
A drain board, also known as a dimpled foundation membrane, is a high-strength plastic sheet engineered to protect foundation walls and manage groundwater. Made from durable high-density polyethylene (HDPE), it features raised dimples that create a permanent barrier and an air gap that relieves hydrostatic pressure against the face of the foundation.
Used by contractors and DIY homeowners alike, drain boards can be installed on the exterior of a foundation to form a permanent waterproof barrier, or on the interior of basement walls to channel water into a sump pump system.
Dimpled drain boards have been trusted for more than 30 years across North America and Europe, proving their performance in millions of installations for both new construction and renovation projects. They are a versatile, long-term solution for keeping foundations dry, stable, and protected.
Drain Boards vs. Drainage Mats — What’s the Difference?
Although the terms are sometimes used interchangeably, drain boards and drainage mats serve slightly different purposes within a waterproofing system. Both products manage groundwater and relieve hydrostatic pressure, but they do so in distinct ways.
- Drain Boards (Dimpled Foundation Membranes): Act as both a waterproof barrier and drainage layer. They are mechanically fastened to the wall and can be installed on the exterior or interior of a foundation. The raised dimples create an air gap that channels water down to the perimeter drain or sump pump while keeping moisture away from the wall surface.
- Drainage Mats: are a dedicated drainage layer that is typically installed over a waterproof coating. The dimples and filter fabric provide a high-flow path for water to drain vertically, protecting the waterproof coating and maintaining consistent flow behind the wall.
In short, drain boards provide a permanent barrier, while drainage mats complement an existing waterproof coating as part of a complete system. Both work together to protect foundations and control groundwater, depending on the design and application.
👉 Learn more about Drainage Mats
How Drain Boards Work
A drain board is a dimpled plastic sheet that can be used for exterior or interior applications.
On exterior applications, a drain board acts first as a permanent waterproof barrier—keeping water and moisture away from the wall surface. The air gap behind the dimples removes headwater pressure of the face of the wall. Water and moisture go to the footing drain for removal.
On interior installations the drain board is attached to the wall and feeds directly into a sump pump.
Key Benefits of Drainage Mats
Drainage mats do more than move water — they protect your entire waterproofing system and improve the long-term performance of the structure. When properly installed, they provide a durable layer of protection, pressure relief, and moisture control that coatings alone cannot achieve.
Why Builders and Engineers Use Drainage Mats
What it's Made From
Drain boards are made from high-density polyethylene (HDPE), a strong and flexible plastic that will not rot, crack, or deteriorate in soil.
HDPE drain boards are chemical-resistant, freeze-thaw stable, and can handle high soil pressure without losing shape.
Applications and Installation Overview
Drain boards are used in residential and commercial foundations to keep walls dry and protected. They can be installed on concrete, block, ICF, and shotcrete foundations.
Common Applications
- Exterior Foundations: Creates a waterproof barrier and directs water to the footing drain.
- Interior Foundations: Channels water into a sump pump for removal.
- Retaining Walls: Relieves pressure and prevents water buildup behind the wall.
- Basement Renovations: Adds protection and drainage to existing walls.
Installation Overview
- Prepare the Wall – Make sure the surface is clean are free of any loose debris. Patch any tie holes, rock pockets and honeycombs and smooth.
- Attach the Drain Board – Fasten it to the wall as per the manufacturers installation instructions.
- Overlaps – Overlap the seams by 6 inches. Apply a layer of mastic between the seams and fasten with plugs.
- Connect to the Perimeter Drain – install drain stone at least 6" above the footing.
- Backfill Carefully – Use clean backfill.
Summary
Drain boards protect foundations by keeping water and moisture away from the wall. They create an air gap that relieves pressure and directs water to the footing drain or sump pump.
When paired with SUPERSEAL Waterproof Coatings, they form a complete waterproofing system that keeps your foundation dry, strong, and protected for years to come.