CSP Coupler

External couplings for joining corrugated metal pipe

The Superior Method for Jointing Corrugated Steel Pipe

MarMac Construction Products Water-Tight CSP Coupler
MarMac Construction Products Soil-Tight CSP Coupler


MarMacʼs CSP 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.

CSP 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 Construction Products Water-Tight CSP Coupler
Features & Benefits
  • Easy to install, permanent & versatile
  • Works on rerolled or non-rerolled ends
  • Galvanized or polymer-coated CSP
  • Infiltration-proof
  • Exfiltration-proof (Watertight version)
  • Strong, shear & puncture-resistant
  • Cost-efficient & readily available

Over engineered.

MarMac CSP 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.


Heavy-duty, cross-laminated top layer, available with UV & chemical resistance


Specially formulated, rubberized mastic aggressively adheres to all concrete surfaces


Puncture & shear resistant reinforcement layer sandwiched between mastic sealant


A protective, peelable release film protects the mastic until ready for use

MarMac Construction Products CSP Coupler Layers

Relentlessly tested.

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.

CSP 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

All typical properties of MarMac CMP couplers are based on, and meet or exceed the material requirements of:

ASTM D 882 (Method A)ASTM D 624 (Die C)ASTM D 570ASTM D 1682


Couplers should be stored carefully in their original packaging, out of direct sunlight and protected from the elements. Materials should be kept away from direct heat, sparks, and open flame. For optimum results, couplers should be stored in a tepid (60°-80°) environment prior to installation.

Ash-inert matter 8% 15%
Volatiles 0.1% 2.0%
Softening temp 175°F
Specific gravity 0.95 1.05
Penetration 60 dmm 90 dmm
Flow 10 mm 10 mm
Tensile strength 4000 psi
Elongation at break 100%
Tear resistance 1500 psi
Water absorption
Tensile strength (Warp) 75 lb/in
Tensile strength (Fill) 75 lb/in
Elongation at break (Warp) 20%
Elongation at break (Fill) 20%

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.



Pipe sizes: 6-144″
Standard, Chemical-Resistant, or UV-Resistant options


New Installations
Detention Systems
Galvanized CSP
Polymer-Coated CSP
Non-Rerolled Pipe
Rerolled Pipe

MarMac Construction Products Watertight CSP Coupler Diagram

Watertight CSP Coupler

Designed as an infiltration and exfiltration-proof sealing solution, our Watertight CSP Coupler connects 6- 42” 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.

MarMac Construction Products Soil-Tight CSP Coupler Diagram

Soil-Tight CSP Coupler

Available in all sizes to connect virtually any diameter of corrugated steel pipe, Soil-Tight CSP Couplers seal both rerolled and non-rerolled pipe ends. They are designed with four evenly-spaced, high-tensile compression bands, each reinforced with butyl rubber underlays. When the bands are tightened, the compressed butyl creates an infiltration-proof, exfiltration-resistant joint.

CSP Coupler Requests

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*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.

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