The NDS 1816 18" x 18" Catch Basin Riser adds up to 8" of height to 18" square catch basins and low-profile adapters. Molded from high-impact polystyrene (HIPS) with UV inhibitors, this black riser provides durable, lightweight extension that resists cracking and corrosion for long-term outdoor use. Adds up to 8" of adjustable height; can be trimmed to fit custom site elevations. Constructed of UV-stabilized HIPS with structural ribs for impact resistance. Includes four interlocking sides for simple stacking and secure assembly. Compatible with 18" catch basin models and 18" square grates; stacks directly on top. Use with NDS universal outlets #1206, #1243, #1245, or #1266 for each opening. Color: black; lightweight design simplifies handling and installation. Designed for residential and commercial drainage applications, the 1816 riser helps collect surface water in lawns, driveways, landscaped areas, and courtyards while keeping larger debris out of the system. For soil-tight joints use waterproof silicone where needed. Refer to the NDS drainage catalog and the 1816 technical spec for complete dimensions, installation guidance, and compatibility information.
