Emseal 25V: Masonry Primary Seal

  • A weather, moisture, vapor, air, sound and dust seal in static or expansion/contraction joints in walls.
  • Generally used as a primary seal
  • Can be used as a secondary seal behind a backerrod (or bond breaker tape) and caulking
  • Suitable for use in substrates of brick, CMU, precast and cast-inplace concrete, wood, stone and most construction materials
  • Used extensively for sealing vertical abutment joints between buildings, brick and CMU control joints, joints in tilt-up panels, etc.
  • Anti-vibration and acoustic seal

Product Data Sheet

Safety Data Sheet

Emseal Checklist


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Emseal 25V: Masonry Primary Seal

Emseal 25V is a long-term, economical, high-performance seal for above-grade wall joints in concrete, brick, stone, etc. where black reveal or shadow-line effect is desired or where installed in concealed conditions. Questions about Emseal 25V? Contact Us.

Emseal Checklist

Note:  The 25V System has been largely replaced for vertical joint applications by Seismic Colorseal. While Seismic Colorseal is usually chosen in preference to 25V, 25V still exists in legacy specifications and continues to be a preference of some specifiers for its appearance.

  • Durable primary seal
  • Permanently elastic and weathertight
  • Follows joint contours
  • Difficult to vandalize

Permanently elastic, high-density, open-cell polyurethane foam, impregnated with water-based, polymer-modified asphalt.

Substrates must be clean, parallel, plumb, have sufficient clear depth to receive the material specified, and be capable of resisting approx. 2.5 psi backpressure from the foam.

  • As with any construction product, the useful life of the material can be maximized with routine inspection and repair if required.
  • Occasional inspection will reveal any damage to the product or adjacent substrates that might affect building performance.
  • EMSEAL precompressed sealants are easily repaired–requiring only damaged sections to be removed and reinstalled–not the entire length of the joint as is typical of extruded-seal systems.


  • 25V 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 4-times compression is required for weather tightness in applications in the vertical plane.
  •  25V is packaged precompressed in reels with adhesive backing or, depending on size, in shrink-wrapped lengths (sticks). See table 2.
  •  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 pressure-sensitive adhesive impregnation and the backpressure of the expanding foam.