Emseal 20H System: Water-Based Asphalt Emulsion

  • Concrete foundations
  • Retaining walls
  • Below-grade expansion gaps
  • Warranted for watertightness
  • Primary seal for exterior vertical below-grade walls in installation from positive side
  • Non-invasive anchoring
  • Conforms to gap irregularities
  • Size switching accommodates joint gap variations
  • Thermally insulating

Technical Data Sheet

Safety Data Sheet

Emseal Checklist


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Emseal 20H System: Water-Based Asphalt Emulsion

Emseal 20H System is a tried and true preformed expanding foam sealant produced by impregnating permanently elastic, high density, open-cell polyurethane foam with an acrylic polymermodified, water-based asphalt emulsion. It is primarily used in below-grade applications. The architectural and engineering community has benefited from Emseal 20H System performance for over 30 years. Questions? Contact Us.

Emseal Checklist

Note:  The 20H System has been replaced for deck joint applications by the DSM System and in below-grade applications by BG System and DSM-DS.  20H System still exists in legacy specifications and for installations in below-grade, positive-side wall joints.

  •  20H is a preformed expanding foam sealant produced by impregnating permanently elastic, high-density, open-cell polyurethane foam with water-based, polymer-modified asphalt.
  •  Partially filling the open-cells with the impregnation and then compressing the material results in levels of sealing depending on the degree of compression.
  •  Typically, approximately 5-times compression is required for watertightness in below-grade and horizontal deck applications.
  •  The 20H foam is packaged precompressed in shrink-wrapped lengths (sticks).
  •  It is supplied precompressed to less than the nominal material size for easy insertion into the joint.
  •  Sealing between the foam and substrate is achieved through a combination of the effects of foam backpressure and the epoxy adhesive applied to the substrates and into which the 20H foam is installed.
  • The exposed or outer surface of the installed 20H is further treated with Topcoat, supplied to suit the application.
  •  The complete 20H System comprises three elements:
    1. the 20H foam,
    2. the epoxy adhesive, and
    3. the Topcoat. See Figure 1.

Uses and Applications:

  •  As a watertight seal in joints including:
    – structural joints
    – perimeter joints
    – roadways
    – sidewalks

– foundation
– planters
– tunnels
– parapets


  •  20H System will not adhere to joints that are dirty or dust-covered or to surfaces coated with oils or release agents.
  •  20H System service temperature range is -40°F to 185°F (-40°C to 85°C).
  •  20H is not resistant to sustained contact with petroleum solvents,
  •  oils, selected waxes, active chlorine, heavy oxidized acids or strong lyes.