click to zoom in

12" MarMac CMP Coupler (CMP to CMP) (Watertight)

No reviews yet Write a Review
Usually Ships in 7-10 Business Days

12" MarMac CMP Coupler (CMP to CMP) (Watertight)


12" MarMac CMP Coupler (CMP to CMP) (Watertight)


MarMacʼs CMP Coupler is a single unit, external sealing band designed to prevent infiltration into corrugated steel pipe drainage systems. The coupling creates a strong, permanent, flexible seal around the joints of rerolled (annularized) or non-rerolled (spiral) CSP pipe ends.

CMP couplers function on traditional galvanized and polymer coated pipe. They are easy to install, cost-efficient, permanent, and readily available. Our dedicated production line and unique manufacturing process allow for quick shipping regardless of coupler size or order quantity.

MarMac CMP Coupler membranes are constructed of cross-laminated layers of rubberized mastic, integrated mechanical compression bands, an internal woven reinforcement, and butyl underlays.

Our proprietary mastic aggressively adheres to the pipe surface, while the integrated compressions bands mechanically seal and form a permanent bond to the full circumference of the pipe walls. The internal woven polypropylene material provides increased shear and puncture resistance. The butyl rubber underlays compress beneath the compression bands and against the pipe wall and joint, forming an infiltration-proof seal on annular, spiral or helical corrugations.

Designed as an infiltration and exfiltration-proof sealing solution, our Watertight CSP Coupler connects 12- 54” diameter corrugated steel pipe with both rerolled and non-rerolled ends. Utilizing five high-tensile compression bands, the center and outer edge bands are reinforced with butyl rubber underlays, which create an exfiltration-proof seal when tightened. Two secondary compression bands straddle either side of the main center strap as a preventative measure.          

  • Size: 12"
  • Works on the following connections:
  • Rerolled (Annular)  to Rerolled (Annular) ends
  • Non-rerolled (Spiral) to Non-rerolled (Spiral) ends
  • Watertight will not work on Rerolled (Annular)  to Non-rerolled (Spiral)
  • Easy to install, permanent & versatile
  • Galvanized or polymer-coated CSP
  • Infiltration-proof
  • Exfiltration-Proof
  • Strong, shear & puncture-resistant
  • Cost-efficient & readily available


***Non-cancellable and non-returnable***

Available in sizes 12" - 54" 


With the help of Pacific Corrugated Pipe Company and National Corrugated Steel Pipe Association‘s technical advisory committee, our coupling was third party tested by Oregon State Universityʼs College of Engineering for hydrostatic pressure tolerance. The Watertight CSP Coupler was found to withstand a minimum hydrostatic pressure of 10.8 psi for over 10 minutes without leakage, making it officially watertight.

CMP Couplers integrate several unique components into a single, full-perimeter, external sealing band. The coupler composition consists of:

  • Heavy duty polyethylene backing
  • Internal woven polypropylene reinforcement
  • High-tensile compression bands
  • Specially formulated mastic contact layer with butyl sealant underlays


The coupler shall be placed around the pipe, mastic side to the pipe, spanning the joint. The protective release film shall be removed and the coupler applied with the overlap at the top of the pipe. The straps shall be secured (outside straps first) on the larger outside diameter pipe (when applicable) with the proper tools; the securing straps on the outside of the smaller outside diameter pipe shall then be secured. The inside strap shall be tightened last. The closing flap shall cover the exposed strap work area, completing the joint.

CAUTION: *All statements and technical information are based on tests and/or data which MarMac Manufacturing deems reliable, however, MarMac does not warrant or guarantee the accuracy or completeness of such information. Please read further manufacturer liability and warranty information.