External riser protection for manhole chimneys
External Manhole Frame/Chimney Seal

MarMac SurSeal provides a permanent, flexible, watertight seal between manhole castings and concrete cones. It combines the advantages of a mechanical seal with the added assurance of a pliable gasket. Its ease of installation & low cost makes SurSeal one of the best options available.

SurSeal is easy to install and designed for simple readjustment when/if grades are required. No special tools, primers, or torches are required for installation. The same tool used to tighten pipe to manhole connectors and flexible couplings is used to tighten the top and bottom bands of SurSeal.

SurSealʼs top band compresses the pliable rubber gasket component, uniformly filling the annular space, forming a gasket seal to the top,
bottom, and outside edges of the frame’s base flange. The band’s “C” shape mechanically locks the seal on the manhole casting. The flat bottom band compresses the pliable gasket component against the top of the concrete cone, instantly filling any minor voids or irregularities.

Features & Benefits
  • Permanent & flexible
  • Easy to install; no special tools, primers, or torches required
  • High performance
  • Low cost
MarMac SurSeal Chimney Riser Seal Graphic
SurSealʼs main sleeve component is made from high-quality EPDM rubber with a minimum thickness of 60 mils and is suitable for both above and below grade applications. Contact MarMac for specifications of SurSealʼs other components.

MarMac SurSeal should be stored in a dry, cool place.

Service Temperature Range -40 °F 250 °F
Application Temperature 20 °F 120 °F
Color Black Visual
Specific Gravity 1.16 ASTM D1475
Solids Content 75 % ASTM C681
Sag or Flow 0.05″ ASTM D2202
Press-Flow Viscosity 55 sec ASTM D2452
Flash Point 48 °F ASTM D56
VOC Content 330 g/L ASTM D3960
Shear Strength 25 psi ASTM D1002
Tensile Strength 25 psi ASTM D638
Elongation 140 % ASTM D638
Shore A Hardness 8-12 ASTM C661
Shore 00 Hardness 50-55 ASTM C661
Resistance to 5% (nitric, sulfuric, & hydrocloric acid) Excellent- No effect after 30 day immersion ASTM D545

Provide a minimum 3/8″ space between the frame and the top adjusting ring, or cone, with two rows of 3/4″ x 3/4″ preformed butyl rubber rope.

To insure a proper seal, clean the edge of the manhole casting and the vertical portion of the cone with a wire brush and remove any resulting residue from the surface. Sealing areas need to be reasonably smooth and free from gross imperfections (some imperfections may require the use of butyl rubber caulk as a means to create a smooth sealable surface). Pull the SurSeal rubber collar over the manhole frame/chimney. Align the top edge of the collar 1″ above the manhole casting flange and position the bottom preformed gasket so that it is centered a minimum of 1-1/2″ below the top of the concrete cone section. Fold both top and bottom edges of the collar back and remove the release paper from the bottom preformed gasket. Flip/ turn the bottom edge back into position.

TOP: Install the extruded gasket (“C” profile) by pulling it over the manhole frame. Press/seal the gasket 360° onto the edge of the flange making sure no twists are encountered. Unfold the collar to cover the gasket. Center the C-contoured compression band around the edge of the frame’s base flange with the gear nut facing to the right. Tighten securely with a 5/16″ socket drive.

BOTTOM: Center the flat band around the preformed gasket and tighten with a 5/16″ socket drive. Tighten the band sufficiently to achieve ~50% compression of the sealant (Do not over tighten).


Diameter: 34”, 36”, & 38”
Height: 11”, 16”, & 20”


Manhole Chimneys

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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.