What lengths and depths are available for NDS Dura Slope?

Dura Slope channel sections are available in 4-foot lengths with 33 different depth variants ranging from 3.99 inches to 12.06 inches. Both sloped (0.7% gradient) and neutral (flat-bottom) configurations are available. Continuous runs can reach up to 132 feet.

What ships with each NDS Dura Slope channel section?

Each Dura Slope channel section ships with two removable blank grate covers and two ProFit Grate Locks. Finished grates, end caps, outlets, catch basins, and iron frames are ordered separately.

How does water drain out of the NDS Dura Slope?

Three options at the deepest end of the run: through the bottom using a bottom outlet adapter (DS-126), through the end using a universal end outlet (DS-227), or through an in-line catch basin (DS-340). Each section also has a knock-out bottom outlet.

Can the NDS Dura Slope system make bends and curves?

Yes. Dura Slope radius couplings provide plus or minus 3 degrees of angular motion, allowing curved runs commonly used at running track ends. Available in four neutral depths.

What is the built-in slope of NDS Dura Slope?

Each sloped section has a factory-molded 0.7% slope with 0.34 inches of fall per 4-foot section. Neutral sections have flat bottoms and are used to extend runs beyond 96 feet.

NDS Dura Slope Trench Drain FAQS and Resources

Q: What is the load rating of NDS Dura Slope Trench Drains?

Standard plastic grates carry a Class B rating (61-175 PSI). Cast iron and ductile iron grates with ductile iron frames carry a Class D rating (326-575 PSI / 89,920 lbs per foot). All ratings assume proper concrete encasement.

Q: Do NDS Dura Slope sections need to be installed in a specific order?

Yes. All channel sections are labeled with part numbers and must be installed in ascending numerical order, starting with the shallowest section. The deepest section connects to the discharge point.

Design & Engineering

Key Features

What makes the NDS Dura Slope the preferred pre-sloped trench drain for engineers, contractors, and architects.

Built-In 0.7% Slope

Each sloped section has a factory-molded 0.34″ fall, eliminating the need to manually grade the trench bed. Sloped and neutral (flat) sections combine for continuous runs up to 132 feet with consistent, engineered drainage.

NDS Dura Slope DuraLoc tongue-and-groove joint system

DuraLoc Tongue & Groove Joints

Unique interlocking joints with an integral snap-lock feature ensure precise alignment and prevent joint movement during installation. No couplings required between channel sections — just connect and lock.

NDS Dura Slope LeveLoc rebar support system

LeveLoc Integral Rebar Supports

Built-in rebar clips at 24″ intervals along each side of the channel grip #3 or #4 rebar (3/8″–1/2″) for easy height adjustment during installation. No separate stakes or tie wire needed.

NDS Dura Slope ProFit grate locking system

Up to Class D with Ductile Iron

HDPE channel body handles Class B loads. Add ductile iron frames and ductile iron grates to achieve Class D ratings (up to 575 PSI / 89,920 lbs per foot) for heavy vehicular and forklift traffic.

Technical Data

Specifications

Key dimensions, materials, and performance data for the NDS Dura Slope system.

Channel Body

Length	48″ (4 ft) per section
Width	6-5/8″
Depth Range	3.99″ to 12.06″ (33 depth variants)
Flow Path Width	4″ nominal (101.6mm)
Bottom Radius	2″ (50.8mm) — facilitates sediment removal
Material	UV Protected High-Density Polyethylene (HDPE)
Built-In Slope	0.7% (0.34″ fall per section)
Connection	DuraLoc tongue-and-groove (no couplings)
Max Run (Sloped Only)	96 ft
Max Run (With Neutrals)	132 ft (up to 266 ft extended)

Grates & Load Ratings

Grate Length	24″ (2 ft) — 2 per channel section
Grate Width	6-5/8″
Grate Height	3/4″
HDPE Grates	Class B — 61–175 PSI
Cast Iron Grates	Class D — 326–575 PSI
Ductile Iron + Frame	Class D — 326–575 PSI
Galvanized Steel	Class C/D (varies by type)
Compressive Strength	2,900 PSI
Tensile Stress	4,550 PSI
Flexural Strength	5,800 PSI

Where to Use It

Recommended Applications

The NDS Dura Slope is engineered for medium- to heavy-duty drainage where pre-sloped channels, high load ratings, and long continuous runs are required. For lighter residential applications, see NDS Mini Channel or Spee-D Channel.

Loading Docks

Handle heavy forklift traffic and manage stormwater at dock aprons. Class D-rated ductile iron grates withstand the heaviest pneumatic tire loads in commercial and industrial settings.

Parking Lots & Garages

Intercept sheet flow across large paved areas. The built-in 0.7% slope eliminates the need to grade the trench bed, reducing installation time and cost on commercial projects.

Running Tracks & Athletic Fields

Drain perimeter runoff at track edges and field borders. Radius couplings allow curved runs to follow track contours. Chemical-resistant HDPE handles de-icing agents and fertilizer runoff.

Pool Decks & Spas

Manage splash-out and rainwater on commercial pool surrounds. HDPE resists chlorine, salt, and UV exposure. Decorative iron grates complement upscale pool environments.

Warehouses & Industrial

Floor drainage in manufacturing, warehouse, and processing facilities. Stainless steel perforated grates handle chemical exposure in food processing and pharmaceutical environments.

Commercial Hardscapes

Driveways, plazas, courtyards, and pedestrian walkways in commercial developments. Six standard plastic grate colors and three decorative iron patterns match any architectural finish.

Customization

Grate Options & Colors

The Dura Slope system offers the broadest grate selection of any NDS pre-sloped channel — from standard plastic in 6 colors to decorative cast iron, ductile iron for Class D loads, galvanized steel, stainless steel, and slot-top grates. All grates are 24″ (2 ft) sections.

24″ · Class D · Requires Frame

Galvanized Perforated

24″ · Perforated

View Details →

Stainless Steel Perforated

System Components

Accessories & Fittings

Each Dura Slope channel section ships with two blank grates and two ProFit Grate Locks. Build your complete system from these additional components.

Getting Started

Installation Overview

Dura Slope sections must be installed in ascending numerical order starting with the shallowest section. Refer to the NDS installation manual and CAD details below for application-specific instructions.

Plan the run and order sections in the correct depth sequence. All sections are labeled with part numbers — install in ascending order from shallowest to deepest. The deepest end connects to your discharge piping.
Excavate the trench to required depth and width, accounting for concrete encasement per your load class (4″ for Class A/B, 6″ for Class C, 8″ for Class D).
Set rebar through the LeveLoc integral clips at 24″ intervals. Use #3 or #4 rebar (3/8″–1/2″) to set channel height — position the top of the channel 1/8″ below the finished surface.
Connect sections using the DuraLoc tongue-and-groove joints. Snap-lock into place — no couplings or adhesive needed between channel sections.
Install drainage connections at the deepest end — bottom outlet adapter (#DS-126), end outlet (#DS-227), or in-line catch basin (#DS-340). Close the shallow end with an end cap.
Tape grate slots and screws before pouring concrete. The included blank grates protect the channel during the pour — discard them after curing.
Encase in concrete per the applicable NDS installation detail for your traffic class.
Install grates once concrete has cured. Seat grates into ProFit Grate Locks and secure. Leave 1/8″ expansion gap between grates. For Class D applications, install ductile iron frames first.

Common Questions

Frequently Asked Questions

Answers drawn from our team's direct experience specifying and selling the NDS Dura Slope system.

Dura Slope channel sections are available in 4-foot lengths with 33 different depth variants ranging from 3.99″ to 12.06″. Sections come in both sloped (0.7% built-in gradient) and neutral (flat-bottom) configurations. The system can achieve continuous runs up to 96 feet using sloped sections only, or up to 132 feet (extendable to 266 feet) with neutral sections included. Each depth variant is numbered sequentially — sections must be installed in ascending order.

Each Dura Slope channel section ships with two removable blank grate covers (which protect the channel during concrete pours — discard after curing) and two ProFit Grate Locks. Finished grates, end caps, end outlets, bottom outlet adapters, catch basins, and iron frames are ordered separately.

Load ratings depend on grate and frame selection, assuming proper concrete encasement. Standard plastic grates (structural foam polyolefin) carry a Class B rating (61–175 PSI). Cast iron and ductile iron grates (with ductile iron frames) carry a Class D rating (326–575 PSI / 89,920 lbs per foot). See our Load Rating Recommendation Guide for details.

Three options, all connecting at the deepest end of the drain run: through the bottom using the bottom outlet adapter (#DS-126) for 4″ SDR35 pipe, through the end using the universal end outlet (#DS-227), or through an in-line catch basin (#DS-340). Each channel section is also molded with a knock-out bottom outlet for system versatility.

Yes. Dura Slope radius couplings provide ±3° of angular motion, allowing the system to form curved runs — commonly used at the ends of running tracks and around curved hardscapes. Radius couplings are available in four neutral depths (6.35″, 7.36″, 8.37″, 9.37″) and connect neutral Dura Slope sections of the same depth. Each radius coupling includes a standard plastic grate.

Dura Slope uses DuraLoc tongue-and-groove interlocking joints — no couplings or adhesive are required between channel sections. The integral snap-lock feature prevents joint movement during installation and ensures precise alignment. Simply push sections together until the snap-lock engages.

Each sloped Dura Slope section has a factory-molded 0.7% slope (0.34″ of fall per 4-foot section). Neutral sections have flat bottoms and are used to extend runs beyond the maximum sloped-only length of 96 feet. NDS does not recommend connecting more than 4 consecutive neutral sections to prevent standing water. With neutral sections properly placed, the system can reach 132 feet with 8.07″ of total fall.

Yes. All channel sections are labeled with an NDS part number sticker. Sections must be installed in ascending numerical order, starting with the smallest (shallowest) part number. The deepest section connects to the discharge point (outlet, catch basin, or bottom adapter). Installing sections out of order will result in improper slope and standing water.

Grates seat into the ProFit Grate Lock system — two locks are included with each channel section. Grate screws are also included with all Dura Slope trench drains and radius couplings. For Class D applications using ductile iron grates, install the ductile iron frame first, then seat the grate into the frame.

All Dura Slope channels ship with removable blank grate covers that protect the channel during concrete work. NDS recommends also taping over the grate slots and screw holes before pouring. After the concrete has been finished and fully cured, remove and discard the covers. The included screws are then used to secure the permanent grates.

Explore Other Options

Other Trench Drain Product Lines

Different projects call for different systems. Here's how the Dura Slope compares to other trench drain lines we carry — and when you might want to consider an alternative.

NDS

Pro Series Channel Drain

NDS's non-sloped commercial workhorse. Available in 3″, 5″, 8″, and 12″ widths with polypropylene construction. Snap-together couplings and Qwik-Turn radius fittings. Choose the Pro Series over Dura Slope when you don't need built-in slope, need wider channel widths, or prefer snap-together assembly over tongue-and-groove joints.

3″ – 12″ Widths Polypropylene Up to Class D Non-Sloped

Shop NDS Pro Series →

NDS

Spee-D Channel Drain

The #1 bestselling residential channel drain in the USA. A lighter-duty 4″ HDPE system with the widest accessory ecosystem of any residential channel — including the new Contour articulating channel for curved layouts. Choose the Spee-D when the project is residential-scale and Class A-B ratings are sufficient.

4″ Width HDPE Class A–B Contour Articulating

Shop NDS Spee-D Channel →

NDS

Mini Channel Drain

A compact 3-1/2″ residential trench drain with brass grate options for upscale hardscapes. Solvent-weld connections and a narrow profile. Choose the Mini Channel for lightweight residential applications where a small visual footprint and decorative brass finishes are priorities.

3-1/2″ Width HDPE Class A–B Brass Grate Options

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NDS

Slim Channel Drain

The newest residential channel from NDS with a narrow 2-1/4″ profile and snap-in grates. Best suited for pedestrian-only applications where a minimal visual footprint is the priority — walkways, amusement parks, and decorative hardscapes.

2-1/4″ Width HDPE Class A Snap-In Grates

Shop NDS Slim Channel →

Josam

Pro-Plus Channel Drain

A fiberglass-reinforced polymer concrete system for commercial and industrial projects. Available in 4″ and 8″ widths. Polymer concrete offers exceptional strength-to-weight ratios and freeze/thaw resistance. Choose Josam when specifying polymer concrete for commercial construction or industrial facilities.

4″ & 8″ Widths Polymer Concrete Commercial Grade

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BG Filcoten

Tec Series Trench Drains

German-engineered fiber-reinforced concrete trench drains in 4″, 8″, and 12″ profiles. Filcoten delivers the structural performance of concrete at a fraction of the weight. A strong alternative to Dura Slope when the specification calls for European-standard fiber concrete construction.

4″ – 12″ Widths Fiber Concrete European Standard

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