DRAINAGE MATS FOR CONSTRUCTION
High flow drainage for a Waterproofing Systems
DRAINAGE MATS FOR CONSTRUCTION
What is a Drainage Mat?
A drainage mat is a dimpled plastic sheet with a filter fabric bonded to one side. It’s typically installed over a waterproof coating to form a complete waterproof drainage system.
The dimples create an air gap provides a drainage path, while the filter fabric allows water to pass through but blocks dirt and fine particles and keeps that drainage path clear and free flowing.
Drainage mats remove the hydrostatic headwater pressure and protect the waterproof coating. They are typically used in commercial and residential applications, including blind walls, shotcrete shoring systems, ICF foundations, concrete foundations, retaining walls, planters, podium decks, and green roofs.
How Drainage Mats Work
A drainage mat is the drainage layer in a waterproofing system. When installed with the waterproof coating, the air gap provides horizontal and vertical drainage paths for water.
The filter fabric is heat fused to the dimpled sheet and prevents soil and fine particles from clogging the drainage path.
Drainage mats:
- Removes hydrostatic pressure off the foundation wall
- Provides the high flow drainage for the waterproofing system
- Protects the waterproof coating from backfill damage
In short: waterproof coatings stop water — drainage mats move it away.
How Drainage Mats are Made
Drainage mats vary in dimple height and compressive strength.
Material Composition
- High-Density Polyethylene (HDPE) is the main plastic used for the dimple sheet for most drainage mats. It provides high compressive strength, chemical resistance, and long-term durability against soil, salts, and groundwater conditions.
- Dimple Profile – The height and shape of the dimples determine the mat’s drainage capacity and compressive strength. Taller or double-dimple profiles provide greater flow and added protection for deeper foundations or shotcrete walls.
- Filter Fabric (Geotextile) – A non-woven fabric bonded to one side of the mat. It allows water to pass through freely while filtering out soil and fine particles that could clog the drainage channels.
SUPERSEAL’s Double Drain with Geo is the only drainage mat on the market that uses a dual-dimple design. It creates a high flow drainage path on both sides of the membrane. The fabric side faces the soil or backfill and the dimple side is installed against the wall or waterproof coating. This provides maximum drainage capacity with the added benefit of dual sides drainage for commercial or high-water-load applications.
The combination of high-strength HDPE and geotextile filter fabric creates a durable, high-flow drainage for the life of the structure.
For projects requiring maximum drainage performance, a dual-sided membrane such as SUPERSEAL’s Double Drain with Geo provides two active drainage paths and enhanced protection for shotcrete, blind wall, and deep foundation applications.
Applications and Installation Overview
Drainage mats are a key component in both commercial and residential waterproofing systems. Their strength, versatility, and consistent drainage performance make them the go-to choice for everything from single-family homes to complex deep-foundation and commercial projects.
Common Applications
- Blind Walls and Shotcrete Shoring Systems – Used as a protective drainage layer between the shotcrete surface and waterproofing membrane. Together, they form a permanent barrier and drainage system that relieves water pressure and protects the wall during backfill.
- Concrete Foundation Walls – Installed over waterproof coatings to manage groundwater, reduce hydrostatic pressure, and prevent damage caused by soil movement.
- ICF Foundations – Protects both the ICF foundation and the waterproof coating, directing water safely down to the perimeter drain without compromising insulation performance.
- Retaining Walls – Controls water buildup behind structural and landscape walls, preventing long-term moisture and pressure issues.
- Planters and Patio Decks – Maintains healthy soil moisture while preventing water intrusion into occupied spaces below.
- Green Roof Systems – Acts as a lightweight, high-flow drainage layer beneath the growing medium, improving root aeration and preventing ponding.
Installation
Proper installation is essential to ensure full system performance. Always clean and prepare the foundation before installation by removing loose debris, oils, or residue and filling any gaps, voids, or honeycombs.
Although specific details vary by project, engineers and architects may provide additional site-specific requirements. The general installation process includes:
- Apply Waterproof Coating – Ensure the waterproof coating or membrane has been properly applied and cured per the manufacturer’s instructions.
For the best results, use SUPERSEAL Waterproof Coating . It's a water-based, instant-set coating that is safe for all foundations, including ICF. It forms a seamless waterproof base layer for the drainage mat. - Unroll the drainage mat and fasten it to the foundation. Depending on the application, the filter fabric may face the wall or the soil, as specified by the engineer.
- Fasten the drainage mat to the wall according to manufacturers instructions.
- Overlap Seams – Overlap adjacent sheets (typically 4"–6"),
- Connect to the Drain Tile – Extend the mat down to the footing or perimeter drain to provide a direct discharge path.
- Backfill Carefully – Use clean, coarse backfill and compact in lifts to prevent damage to the mat or coating.
- Tip: For high-performance or deep-foundation applications, pair SUPERSEAL Waterproof Coatings with SUPERSEAL’s Double Drain with Geo.
Summary
Drainage mats are an essential component of any modern waterproofing system. They protect the wall, relieve hydro-static pressure, and control the flow of water in both commercial and residential applications.
When paired with SUPERSEAL Waterproof Coatings and SUPERSEAL’s Double Drain with Geo, you create a complete, high-performance waterproofing system that provides seamless protection, dual-sided drainage, and maximum drainage.