External waterproofing wrap for concrete structures

Waterproof sealing membrane for precast structures

SealWrap Options

SealWrap Roll icon - MarMac Construction Products
Repair Coupler - MarMac Construction Products
Repair Kit
MarMac Construction Products Manhole Wrap Pack
Manhole Wrap Pack

MarMacʼs SealWrap is a high performance waterproofing membrane used for sealing the joints of precast concrete structures. Compared to other sealing membranes, SealWrap is considered heavy duty due to its puncture & tear resistant internal reinforcement layer.

SealWrap comes in easy-to-transport rolls available in multiple widths, and is also available as a complete repair kit or in Manhole Wrap Packs. The product is not appropriate for use over expansion joints or joints that move.

*Custom roll lengths & widths (up to 36″) available upon request.

Features & Benefits
  • Aggressive tack & initial adhesion to all concrete surfaces
  • Continuous adhesion after backfill
  • Puncture & tear-resistant
  • Infiltration & exfiltration-resistant
  • Resistant to drying, oxidation & hardening
  • Primer not typically needed
  • Economical & effective
  • Available in a range of sizes

Designed for durability.

The product is composed of three separate elements: a proprietary, bitumen-derived mastic; a durable polyethylene backing; and an internal reinforcement layer of puncture and tear-resistant, woven polypropylene. These elements are cross bond laminated during production to create an inseparable, multi-layer wrap.


Heavy-duty, cross-laminated top layer


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

Lift Hole Patch design - MarMac Construction Products

SealWrap meets or exceeds all requirements of ASTM C877, with the exception of Type III scope only covering butyl-based mastics and does not set material specs for bitumen-based mastics. MarMacʼs mastic exceeds the material specs set forth in C877, Type II which addresses the standard for rubberized asphaltic mastic.

Parts of ASTM C990 are commonly referenced for exterior wraps. SealWrap meets the physical requirements for Bitumen Sealants with the exception of the softening point. MarMacʼs mastic softening point is, by design, much lower (175°F) than the specified 320°F. Our material is designed for limited and controlled softening at any temperature above 40°F to achieve a unique initial tack strength and so the material continuously bonds with the concrete’s porous surfaces.

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%

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

The surface of the structure to be sealed should be clean of dirt and debris. The surface should be as dry as possible in field conditions. Specified width of wrap shall be placed against the structure, mastic side to the structure, spanning the joint to be sealed. The protective release film shall be removed from the edge of the wrap and be applied to the structure wall centering the joint gap. Continue to remove the release film as the wrap is applied in full circumference, while keeping hand tension to prevent wrinkling, ensuring adhesion and alignment. The wrap should overlap itself a minimum of half of the SealWrapʼs width with the overlap at the top of the pipe in an accessible position. Hand press the overlapped edges to ensure a seal.



Roll Width: 6, 9, 12, 16, 20, 28”
Roll Length: 60′
Thickness: 3mm


Reinforced Concrete Pipe
Box Culverts
Manhole Sections
Detention & Retention Systems
Burial Vaults
Tornado Shelters

Repair Coupler - MarMac Construction Products

SealWrap Repair Kit

Convenient Kit for Gravity-Flow Pipe & Infrastructure Repairs
MarMacʼs SealWrap comes in a convenient, preassembled kit with everything needed to repair and/or prevent inflow or infiltration into the joints of gravity flow pipe systems or precast concrete structures. SealWrap Repair Kit includes:
  • MarMac SealWrap
  • Stainless Steel Compression Bands (5/8” x 150ʼ)
  • 5/8“ Seals 1
  • Strap Sealing Tool
1 Tensioning ratchets can be supplied for no-tool installation.

Manhole Wrap Packs

Cut-To-Length Rolls & Spray Adhesive for Manhole Joints
MarMacʼs Manhole Wrap Packs are preassembled kits containing everything needed for sealing multiple manhole joints. Manhole Wrap Packs include:
  • 6” wide rolls of cut-to-length SealWrap
  • One can of general purpose Camie® 343 Spray Adhesive
MarMac Construction Products Manhole Wrap Pack

SealWrap 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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