A drain cell mat works by creating an efficient, continuous drainage cavity that manages and channels excess water away from various surfaces, particularly in challenging environments like landscaped roofs.
At its core, a drain cell mat functions by providing a drainage cavity. This cavity is an elevated, void space created by the structured design of the mat modules.
The Mechanism of Water Management
- Modular Structure: Drain cell mats are typically made from lightweight, high-strength recycled plastics. They consist of individual modules designed to interlock. These drain cell modules are easily interlocked in the same plane or at right angles to one another, allowing for flexible installation across various shapes and contours.
- Creating the Drainage Cavity: When installed, the unique grid or cup-like structure of the drain cell elevates the overlying material (e.g., soil, aggregate, paving) away from the underlying substrate (e.g., waterproofing membrane, sub-base). This creates a distinct, open void or drainage cavity underneath the surface.
- Efficient Water Flow: Water that penetrates the surface material (like rainwater through soil on a green roof) flows down until it reaches the drain cell layer. Instead of saturating the underlying layers or building up hydrostatic pressure, the water enters the created drainage cavity. Within this cavity, the water can then flow freely and rapidly in a horizontal direction along the paths created by the cell structure, directing it towards a designated drainage outlet or pipe.
Key Applications and Benefits
The functionality of a drain cell mat offers significant advantages in specific applications:
Landscaped Roofs and Green Roofs
One of the most prominent uses of a drain cell is in landscaped roofs and green roof systems. In this context, its working mechanism provides dual benefits:
- Drainage: It efficiently drains excess water from the soil profile, preventing waterlogging that can harm plant health and put undue stress on the roof structure.
- Protection for Waterproofing: When used in a landscaped roof, it provides additional protection layer for the waterproofing membrane. The rigid structure of the drain cell shields the delicate waterproofing layer from physical damage caused by root penetration, construction activities, or subsequent landscaping work.
- Eliminates Gravel Course: Crucially, it eliminates the need for a gravel course. Traditional drainage layers often rely on heavy gravel, which adds significant dead load to the roof structure. By replacing this, drain cell mats offer a lightweight yet highly effective alternative, making green roofs more feasible and sustainable.
Sub-Surface Drainage
Beyond green roofs, drain cell mats are highly effective for general sub-surface drainage, preventing water accumulation and ensuring stable ground conditions.
Benefits of Using a Drain Cell Mat
The unique working principle of a drain cell mat translates into several practical advantages:
| Feature | Benefit |
|---|---|
| Efficient Drainage | Rapidly removes excess water, preventing waterlogging and hydrostatic pressure. |
| Lightweight | Significantly reduces structural load compared to traditional gravel drainage. |
| Membrane Protection | Shields underlying waterproofing from physical damage and root intrusion. |
| Ease of Installation | Interlocking modules allow for quick, simple, and flexible setup. |
| Aeration | Promotes healthy root growth by ensuring proper aeration in soil layers. |
| Cost-Effective | Reduces material and labor costs associated with heavy aggregates. |
In summary, a drain cell mat works by providing a structural, elevated void that acts as an efficient drainage pathway, simultaneously protecting underlying membranes and offering a lightweight, easy-to-install solution for various water management challenges.
