Watertight Expansion Joints and Construction Sealants by EMSEAL

20H System

Below-Grade Wall Expansion Joint

The 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 20H System’s performance for over 30 years.

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 System

Below-Grade Wall Expansion Joint


  • 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



Nominal Sizes: 1/2″ (12mm) to 4″ (100mm)


Up to 50% Total (+25% and -25% of nominal supplied size.)




  • Concrete foundations
  • Retaining walls
  • Below-grade expansion gaps
  • Available for shipment internationally.
  • Prices are available from local distributors or representatives. For more information, contact EMSEAL.
  • The product range is continually being updated, and accordingly EMSEAL® reserves the right to modify or withdraw any product without prior notice.