An NDS channel drain grate is the removable top of a channel drain, the part you see at the surface, that lets water in while blocking leaves and debris. NDS offers grates in a range of materials and styles, from plastic in several colors to decorative botanical and wave patterns and heavy-duty cast iron, so the grate can match both the look and the traffic of the installation.

What does the grate do?

The grate is the frontline of a channel drain. It admits surface water into the channel while blocking leaves and debris that would otherwise clog the system, and it provides the walkable, sometimes drive-over surface across the channel. Because it is removable, the grate also gives access for cleaning the channel underneath.

Grate materials and styles

• Plastic grates in white, gray, black, sand, green, and brick red, light and economical for residential runs.
• Decorative grates in botanical and wave designs that dress up the visible surface.
• Cast iron grates for durability, heavier traffic, and a premium look.
• Brass grates for a high-end decorative finish on Mini Channel runs.

Matching the grate to the drain

Grates are sized to their channel line, so a Mini Channel grate fits the Mini Channel, a Slim Channel grate fits the Slim Channel, and so on. Choose the material for the traffic (plastic for light foot traffic, cast iron for heavier or drive-over use) and the style for the look. Always match the grate to the specific NDS line and width.

Choosing a grate

Decide on traffic and appearance, then pick a grate in the right material and style for your channel line. The Channel and Trench Drain Selector can help match grates to your drain.

Installation: slope, base, and concrete surround

Grates are set as the final step of an install that uses a concrete bed, a slope to the outlet, and a concrete surround.

The NDS plastic channel lines (Micro, Slim, Mini, Pro Series, and Spee-D) install with the same core method: a leveled gravel and concrete base, a positive slope toward the outlet, and a concrete surround that locks the channel in place flush with the finished surface.

1. Excavate the trench. Dig along the drainage line wider and deeper than the channel itself, allowing room on the bottom and both sides for a concrete bed and surround (a common rule of thumb is roughly 3 to 4 inches of concrete beneath and around the channel, though you should follow the project drawings).
2. Set a slope toward the outlet. Surface drainage needs fall to move water. A widely used target is about 0.5 to 1 percent (roughly 1/8 inch of drop per foot of run), pitched toward the outlet end. On flat sites you create this by grading the trench bottom; check it with a level and string line before you commit.
3. Lay a concrete bed. Place a bed of concrete in the bottom of the trench and seat the channel into it at the right height and slope, so the top of the grate will finish flush with the surrounding hardscape.
4. Stabilize with anchor clips or stakes. Use the line's anchor clips or 6 inch profile installation stakes to hold the channel at the correct height and alignment so it does not float or shift when concrete is placed around it.
5. Pour the concrete surround. Place concrete up both sides of the channel to encase it. Keep the grate or a protective cover on during the pour so concrete does not enter and set inside the channel.
6. Finish flush. Bring the surrounding concrete or pavers level with the top of the grate so water sheets cleanly into the channel and the grate is not a trip hazard.

Getting the slope right

Slope is the single most important detail. Without fall toward the outlet, water sits in the channel instead of draining. For straight channel lines, grade the trench bottom to about 0.5 to 1 percent toward the outlet. The Dura Slope line removes this step by building a 0.7 percent slope into its stepped sections. Either way, confirm positive drainage with a level before the concrete sets, because corrections are difficult afterward.

The concrete surround

A channel drain is only as stable as the concrete around it. The channel should sit on a concrete bed and be encased on both sides so it cannot shift or float, with the grate finishing flush with the surrounding surface. The depth and strength of that surround should match the traffic: light foot traffic on a patio needs far less than a driveway or a commercial area that sees vehicles, where a thicker, reinforced surround and a load-rated grate are required. Always follow the project drawings or manufacturer guidance for the bedding and surround dimensions.