MacWrap Coupler

External couplers for jointing 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 Kit


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.

Over the course of several decades with very few design 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.

Features & Benefits
• Strong, permanent, shear & puncture resistant
• Easily installed & immediately inspectable
• Millions installed with an impressive success rate
• Full-perimeter, positive seal = infiltration-proof
• Specially-formulated mastic layer
• Heavy-duty, high-quality design
• Protection from corrosion, acids & alkali (see MacWrap CR)

Overbuilt to be the best.

MacWrap Couplers integrate several unique components into a single, customizable, full-perimeter, external sealing band. Our specially-formulated mastic provides a positive seal against infiltration. The coupling membrane 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


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


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

MarMac Construction Products MacWrap Coupler Construction
MarMac Macwrap Installation Side View

MacWrap integrates 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

MarMac MacWrap meets or exceeds all requirements of the industry standards for external joint seals of RCP and concrete structures set by:

  • ASTM C877, Type II
  • 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%

MacWrap Couplers should be stored carefully in their original packaging, out of direct sunlight, and protected from the elements. Keep 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.

Surface preparations: Inspect the outside of the joint. Brush and/or repair surface as needed to ensure there are no loose materials or voids. If installing on horizontal pipe, dig the bell hole for complete access to the joint.

The coupler shall be placed around the pipe, mastic side centered on the pipe joint, and then the protective release film shall be removed. The straps will then be tensioned and secured with preinstalled ratchet tensioners. The closing flap shall cover the service area and exposed straps, completing the installation. Backfill may commence immediately following the inspection of proper sealing band installation.

Step-by-step photo instructions can be found in the MacWrap data sheet.



Standard, Chemical-Resistant, or UV-Resistant options

* Refer to version section for sizing.


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

MacWrap for RCP (Reinforced Concrete Pipe) is a high performance, external joint coupler designed for the prevention of infiltration and resistance of exfiltration at joints of bell-and-spigot, tongue-and-groove, round, or elliptical RCP.

MacWrap’s specially formulated mastic is designed to aggressively adhere to the exterior concrete pipe surface, with the tightened mechanical straps creating a nearly 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

MacWrap for Manholes is an advanced, external joint coupler specifically designed for preventing infiltration and resisting exfiltration at connections of precast 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

MacWrap for Box Culverts is 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 amongst the best methods of preventing infiltration of subsurface materials into a box culvert.

MacWrap for Box Culverts is designed to be both leak and puncture resistant against aggressive backfills.


External seals for RCP with hydrocarbon solvent resistance

Chemical Resistant MacWrap (MacWrap CR) is a permanent, external sealing band for RCP of all sizes and shapes. MacWrap CR is backed by a proprietary coextruded barrier film, resistant to hydocarbons and most known chemical polutants, and is designed to be used in areas where these pollutants are present and concentrated. MacWrap CR is typically specified for gravity flow applications, such as stormwater and sanitary sewer installed in contaminated soils, especially those contaminated by hydrocarbons.

MacWrap CR is designed to be infiltration-proof and exfiltration-resistant. In addition, MacWrap CR is proven to maintain the joint integrity, even given less than perfect bedding conditions. It has been tested per ASTM F739 against a battery of chemicals at 95% concentration for permeation resistance with outstanding results. A complete list of test results is available in the MacWrap data sheet.
MarMac Chemical & Corrosion Resistant Coupler
Repair Coupler - MarMac Construction Products


External seals for RCP & manhole joint rehabilitation

MacWrap Repair Coupler is 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.

With its membrane comprised of the same materials as a standard MacWrap, the width of MacWrap Repair Couplers is increased to 24”, four compression bands are utilized versus the standard two, and the thickness is increased by approximately 50%. This is a heavy-duty, 3-ply coupler as the membrane contains an additional layer of polyethylene and mastic.

MacWrap 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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