MacWrap Coupler

External couplers for jointing of precast concrete structures

The Best Solution for Jointing Concrete Structures

MarMac MacWrap for RCP concrete pipe coupler
Concrete Pipe
MarMac MacWrap for Manholes
MarMac MacWrap for Box Culverts
Box Culverts
MarMac Chemical & Corrosion Resistant Coupler
Chemical Resistant
Repair Coupler - MarMac Construction Products
Repair Coupler


MarMac MacWrap is a highly-advanced, external joint coupler designed to permanently prevent infiltration at precast concrete structure connections, including reinforced concrete pipe (RCP), manhole sections, box culverts & stormwater retention systems, and many other round or elliptical concrete structures.

Overbuilt to be the best.

MacWrap integrates several unique components into a single, customizable, full-perimeter, external sealing band. Our specially formulated mastic provides a positive seal, battling infiltration. The coupler is reinforced by internalized woven polypropylene with a heavy duty polyethylene backing and secured by high-tensile compression bands with tensioning ratchets.


Heavy-duty, cross-laminated top layer, available with UV & chemical 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 all concrete surfaces

MarMac MacWrap Coupler Construction
MarMac Macwrap Installation Side View
Features & Benefits
  • Strong, permanent, shear & puncture resistant
  • Easily installed & immediately inspectable
  • Millions of couplers spanning several decades 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 (see MacWrap CR)

Over the course of several decades with very few manufacturing iterations, millions of these couplings have been installed around the world. With nearly a 100% success rate, MacWrap is the proven, premiere solution 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, MacWrap always succeeding where competitors’ products fail, and an excellent choice for both the rehabilitation of failed joints and new installations.

Coupler composition:

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

MarMac MacWrap Couplers meet or exceed all requirements set by ASTM C877 (Type II) and ASTM C1244.

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%
A bell hole shall be dug under the joint to be sealed, adequate in size to safely access the full circumference of the joint. The seal shall be placed around the pipe, mastic side to the pipe joint, and then the protective release film shall be removed. The steel strap will then be tensioned and secured with preinstalled ratchet tensioners or with proper tools. The closing flap shall cover all remaining exposed straps, completing the installation. Backfill can commence immediately following the inspection of proper sealing band installation.


MacWrap for RCP
MacWrap for Manholes
MacWrap for Box Culverts
MacWrap Chem-Resistant
MacWrap Repair Coupler


Bell & Spigot RCP
Tongue & Groove RCP
RCP Repair
Manhole Repair
Box culverts
In-ground applications
Above-ground applications

MarMac MacWrap for RCP concrete pipe coupler

MacWrap for RCP

External seals for reinforced concrete pipe joints

A high performance, external joint coupler designed for the prevention infiltration and exfiltration at joints of bell-and-spigot as well as tongue-and-groove reinforced concrete pipe.

MacWrap’s specially formulated mastic is designed to aggressively adhere to the exterior concrete pipe surface, with the tightened mechanical straps creating an indestructible seal. MacWrap for RCP  is permanent, immediately inspectable, and boasts a 100% success rate. Simply put, MarMac MacWrap is the best there is.

MacWrap for MANHOLES

External seals for precast manhole structures

An advanced external joint coupler specifically designed for preventing infiltration at connections of manhole sections.

MacWrap for Manholes is designed to be installed in the worst field conditions, permanently protecting manholes from infiltration and exfiltration, succeeding where other couplers & seals fail.

MarMac MacWrap for Manholes
MarMac MacWrap for Box Culverts


External seals for stormwater retention systems & 4-sided structures

An external sealing band that creates a full perimeter seal on all four sides of a stormwater detention system. A specially-formulated, aggressive mastic combined with integrated compression bands makes MacWrap the best method of preventing infiltration of subsurface materials into a box culvert. MacWrap for Box Culverts is designed to be leak proof and puncture-resistant against aggressive backfills.


External seals for RCP with hydrocarbon solvent resistance

Chemical Resistant Macwrap (MacWrap CR), is engineered to be a permanent external sealing band for RCP of all shapes and sizes. These couplers are typically specified for gravity flow applications, such as storm water and sanitary sewer / wastewater when installed in contaminated soils, principally hydrocarbon-based. MacWrap CR will prevent groundwater from entering the system at the joint, as well as maintain the joint integrity even given less than perfect bedding conditions. Our chemical-resistant coupling has a proven track record spanning over 3 decades, as an assurance against joint failure, joint rehabilitation, and hydrocarbon solvent resistance.

MacWrap CR’s structure includes a proprietary co-extruded, multi-layer barrier film laminated to the outside of the coupler. This film has been tested per ASTM F 739 against a battery of chemicals at 95% concentration for permeation resistance with excellent results, including benzene, toluene and other hydrocarbon-based solvents. A complete list of test results is available upon request.

MarMac Chemical & Corrosion Resistant Coupler
Repair Coupler - MarMac Construction Products


External seals for RCP & manhole joint rehabilitation

An advanced, external joint coupler, specifically designed to repair compromised joints of precast structures while simultaneously preventing infiltration. MacWrap Repair couplings can be used for the rehabilitation of tongue & groove and bell & spigot reinforced concrete pipe as well as manhole sections, restoring the integrity of damaged joints.

MacWrap Coupler Requests

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Other Products

*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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