Dur-A-Flash Joint Guard System
Flexible Copolymer Liquid Applied Transition Membrane

Above 2°C (35°C)

8 – 9 m2 (85-100ft2)/ 10kg pail  (260 – 300 LF @ 4” wide or 175-200 LF @ 6” wide)


Dur-A-Flash Joint Guard is an extremely flexible waterborne coating with multi-function features that can be used in conjunction with most of Durex Water Resistive Barriers as a tie-in membrane to seal substrates around windows, doors and other openings.

  • Highly flexible, bridges crack which may form in the substrate
  • Vapour permeable, minimizes risk of condensation in the wall from water vapour diffusion
  • Liquid application assures a monolithic, seamless membrane
  • Water resistive (WRB) air barrier membrane & tie-In membrane
  • Exceptional adhesion to a multitude of substrates
  • Self-seals around nails, forming a tight, seamless barrier against water and air leakage

Dur-A-Flash provides an effective, water-resistant transition membrane to provide continuity of Durex Water Resistive Barriers between different substrate materials and to bridge across sheathing joints, at openings, at inside and outside corners, and is an acceptable alternative to Durex EIFS Tape.  It can also be used to bridge across sheathing joints and other construction joints.  When used in combination with Durex Barrier Seam Tape,  Durex Dur-A-Flash Joint Guard provides the continuity of the WRB/Air barrier around window and door rough openings and functions as well as a tie-in membrane over window flanges and door jambs, providing easier application than other conventional products (i.e. butyl flashing tapes or plastic sill pans).

Dur-A-Flash Joint Guard could be applied to most common surfaces such as concrete, brick, concrete block, glass-mat coated gypsum, cement board, Plywood and Oriented Strand Board (OSB) and integrated into various Durex® EIF Systems for both new and retrofit construction

Physical Properties
Product Type

Water-based copolymer


White viscous material in its liquid state

Specific Gravity


300% elongation at break

ph Level


Application Temperature

Above 2°C (35°C)


8 – 9 m2 (85-100ft2)/ 10kg pail  (260 – 300 LF @ 4” wide or 175-200 LF @ 6” wide)

Performance Properties
Method Results
Bond Strength


0.62 MPa (90 psi) glass matt gypsum 1.90 MPa (275 psi) on concrete

Tensile Strength


0.83 MPa (120 psi)



300% elongation at break

Joint Disruption Resistance

CCMC E.1-16

PASS 2mm & 4mm Joints  (deflection up to L/180)

Nail Sealability

ASTM D1970

PASS no water penetration

Air Leakage
  • CAN/ULC S741

(Standard for Air Barrier Materials)

  • ASTM E-2178-13

(Standard Test Method for Air Permeance of Building Materials)

  • PASS   requirement <0.002 L/(s.m2)  @ 75 Pa 
  • Actual 0.0015L/(s.m2)  @ 75 Pa @ 0.57mm (0.023”) DFT

* The results listed above are based on averages, including a margin of error, considering that Durex® Dur-A-Flash may be applied to various substrates with or without irregularities.

Water Resistance / Water Column

AATCC 127 (modified)

(Water Resistance – Hydrostatic Pressure Test)

Resist 55 cm (21.6”) water for min 5 hours

PASS -  No water Leakage after UV exposure and accelerated aging cycling

Water Vapour Permeance


  • Thickness: @ 1.0mm  (0.040”) WFT
  • Method B: 450 ng/Pa.s.m2 (7.9 perms)

AATCC ( AC148 sec. 4.6)

No Cracking when bent over 1/8” (3.2mm) mandrel at 00C (320F)