0.060″ bitumastic with HDPE backing


High Performance Water-Proofing Membrane for Culvert Structures

MarMac SealWrap is a high performance water-proofing membrane with a dual layer joint wrap between 6” and 36” in width and 0.065” in thickness. The product is composed of two separate elements, a proprietary, specially formulated bitumen derived mastic and a heavy-duty puncture and tear resistant HDPE backing. These two elements are cross bond laminated during production to create an inseparable dual layer product with the purpose and descriptions below.

Mastic: The mastic used in MarMac SealWrap is specially formulated to adhere to all known concrete surfaces. The mastic is a bitumen/asphaltic base blended and processed in a proprietary formulation with rubberizing admixtures to result in an extremely aggressive, high tack, and “cold flow” mastic. This mastic therefore has the unique ability to continuously flow into and bond with the porous surface of concrete at ground temperatures. The mastic increases in adhesion the longer it is applied to the surfaced its resulting performance increases with time applied as well. The working lifespan of the mastic, when stored and applied properly, has shown be indefinite. The mastic has shown some ability to selfheal from punctures and tears, and we therefore consider it to be puncture and tear resistant. Our mastic and wrap do not typically need primers of any type. It may be appropriate/desirable to use primer when sealing joints below freezing or in excessively wet conditions. After backfill and at ground temperatures below the frost line, the mastic will continue to adhere even without primers.

HDPE Backing: MarMac pioneered the use of HDPE backings on all of its couplers and seals. Our modern HDPE backing heavy duty, tear and puncture resistant. HDPE is used because it has shown to be one of the most chemically inert materials available, being resistant to bases and alkaline present in most substrates and in stormwater. All HDPE and therefore all of our backings are, however, susceptible to damage from high concentrations of hydrocarbons and to UV exposure. MarMac offers backings on its couplers and wraps that are fully resistant to both UV or high concentrations of hydrocarbons upon request.

MarMac SealWrap meets or exceeds the material requirements of ASTM C 877 and ASTM C 990. Its used for sealing the joints of reinforced concrete pipe, box culverts, manholes, 3-sided concrete structures (including detention and burials vaults and tornado shelters), arches, spans and other below ground concrete structures. It is not appropriate, however, for use in expansion joints or on joints that move.

Sealing Capabilities:
  • Aggressive Tack and initial adhesion to all concrete surfaces.
  • Continuous adhesion at ground temperatures after application.
  • Puncture and Tear Resistant
  • Infiltration and Exfiltration Proof
  • Resistant to drying, oxidation, hardening
  • Primer not typically needed
  • Economical and Effective
  • Available in a range of widths and lengths


Tell us about your application and let our experts help find the best solution for your situation—and send you a free quote!

Also ask about MacWrap for Manholes, RCP and Box Culverts.