Dissimilar Pipe Coupler

External couplers for joining pipes of different materials

The Right Way to Join Pipes of Different Materials

Common Connections

MarMac Construction Products Dissimilar Pipe Coupling RCP to HDPE
MarMac Construction Products Dissimilar Pipe Coupling CMP to HDPE
MarMac Construction Products Dissimilar Pipe Coupling CMP to RCP
MarMac Construction Products Dissimilar Pipe Coupling Ductile Iron to HDPE
Ductile Iron > HDPE

MarMac Dissimilar Pipe (DP) Couplers are reinforced, rubberized mastic, external sealing bands that are engineered to join, seal, and restrain the connections between pipes of differing material and/or pipes of a similar nominal size*, while preventing infiltration into the gravity-flow drainage system.

With hundreds of designs, MarMac DP Couplers are able to join virtually any scenario of pipe combinations. Our most commonly joined pipe materials are reinforced concrete pipe (RCP), corrugated metal pipe (CMP), corrugated plastic pipe (HDPE/HDPP), ductile iron (DI), PVC pipe, vitrified clay pipe, and more. Additionally, DP Couplers make a great choice for connecting BMP separator systems.

DP Coupler Dissimilar Pipe CMP to HDPE - MarMac Construction Products

The minimum length of a DP Coupler is the circumference of the larger outside diameter (if applicable) plus eight inches for overlap. MarMac Dissimilar Pipe Couplers are easy to install, cost-efficient, permanent, readily available, and fully customizable.

* The typical maximum size difference of pipes is 6-8”, dependent on pipe material(s) and/or overall pipe diameter(s), in order to allow for proper step-down. Please contact MarMac for more information.

Universal Dissimilar Couplers Available

Your go-to coupler for joining size-for-size pipes. From “B” wall RCP (w/o bell) down to SCH40 PVC, and every other type of pipe in that nominal size. Universal DP Couplers are heavy duty with 3-ply, 180 mil thickness, and are designed with 4-compression bands to mechanically seal the coupler to the pipe walls. A custom DP Coupler is required for any non-rerolled CMP.

Designed to Perform.

DP Couplers integrate several unique components into a single, customizable, full-perimeter, external sealing band. MarMac’s specially-formulated, rubberized mastic aggressively adheres to all known pipe surfaces, providing a positive seal to battle infiltration. The coupling is reinforced with a sheet of durable, woven polypropylene which provides shear and puncture resistance. An outside backing of heavy-duty, cross-laminated polypropylene protects the joint from future infiltration, acids, and bases. DP Couplers have four integrated compression bands, that when tightened,  form a mechanical seal, permanently bonding the mastic to the pipe wall.

MarMac Construction Products Dissimilar Pipe Coupler Construction

Heavy-duty, cross-laminated top layer, available with acid & alkali resistance


Puncture & shear resistant reinforcement layer sandwiched between mastic sealant


High-tensile compression straps tighten to create an impermeable mechanical seal


Specially-formulated, rubberized mastic aggressively adheres to the pipe surface


Features & Benefits
  • Strong, permanent, shear & puncture resistant
  • Easily installed & immediately inspectable
  • Tens of thousands in use today with nearly a 100% success rate
  • Full-perimeter, positive seal = infiltration-proof
  • Specially formulated mastic layer
  • Heavy-duty, high quality construction
  • Protection from corrosion, acids & alkali

Over the years MarMac DP Couplers have sealed tens of thousands of connections between different types and sizes of pipe. MarMac Dissimilar Couplers are the proven, permanent pipe coupling for the most challenging of installations, and the “go to” solution for when it really matters.  Designed to be installed in the worst field conditions, DP Couplers always succeed where competitors’ products fail.

Our dedicated production line and unique manufacturing system allow us to quickly ship small or large quantities of DP Couplers, custom designed specifically for almost any type and size of pipe you encounter in the field. Many DP Couplers are available for shipping the same day the order is placed, and we regularly ship to job sites and/or drop ship directly to customers or end-users.

DP Couplers are strategically manufactured with cross-laminated polyethylene, woven polypropylene, rubberized “cold-flow” mastic, as well as integrated compression bands, similar to MarMac’s PolySeal couplers. DP Couplers are three-ply with a total thickness of approximately 180 mils. See the Typical Properties table for more information.

MarMac makes no claim regarding the hydrostatic performance of this product in field applications since the character of installation can neither be predicted nor controlled by MarMac.

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°F) 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 0.01%
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. Then, the straps on the outside of the smaller outside diameter pipe shall be secured. The inside straps shall be tightened last. The closing flap shall cover the exposed strap work area, completing the joint.


All sizes of gravity flow pipe


Reinforced Concrete Pipe
Corrugated Metal Pipe
Vitrified Clay Pipe
PVC (gravity flow)
Ductile Iron Pipe
+ More


Some of our most popular pipe jointing scenarios are below. This is by no means a comprehensive list or a suggestion that these connections perform better than others. Dissimilar Pipe Couplers are able to join virtually any structurally sound pipe material will another. DP Couplings are also a great choice for two pipes of the same material, but differing nominal diameter. The aforementioned diameters however, must be reasonably close to account for proper step-down/reduction.

Curious if a Dissimilar Pipe Coupler is the right choice for your job? Contact us today and tell us about your installation scenario using the form below!

MarMac Construction Products Dissimilar Coupler



MarMac Construction Products Dissimilar Coupler 2
MarMac Construction Products Dissimilar Coupler 3


Ductile Iron / HDPE

MarMac Construction Products Dissimilar Coupler

Dissimilar Pipe Coupler Requests

We’re here to help! For purchase inquiries, additional information, or questions regarding our Dissimilar Pipe Coupler, fill out the form below.

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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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