Dur-A-Mastic 100
Water-Based Acrylic Water Resistive Barrier (WRB) Air Barrier
Technical Performance Features
Vapour Permeance - 248 ng/ (Pa.s.m²)

19 m2/pail (205 ft2/pail)


Dur-A-Mastic 100 is a water-based acrylic, ready-mixed, single-component product. Its primary use is as an air/water-resistive barrier (WRB). It is also used as an adhesive to bond expanded polystyrene insulation to wood substrates. When used as a WRB, it meets the requirements for moisture-sensitive substrates as well as an air barrier membrane. It is applied by trowel and it cures to form a tough, seamless, elastomeric membrane, which is resistant to air leakage and water ingress under hydrostatic pressure.

  • Highly flexible, bridges cracks  which may form in the substrate
  • Trowel application assures a monolithic, seamless membrane
  • Prevents air leakage and water ingress through porous building materials
  • Remains firmly bonded to the substrate even when applied over damp surfaces
  • Non-toxic
  • One component; ready to use
  • Odourless
  • Easy clean up with water

Dur-A-Mastic 100 is used as an air barrier within the building envelope and as a seamless WRB membrane. It may be applied to most common surfaces and integrated into various wall systems in both new construction and restoration. Dur-A-Mastic 100 is an Air Barrier and a WRB. 

Typical uses are:

  • Water-resistant/air barrier WRB for EIFS application
  • Plywood/OSB, cement board & exterior-grade gypsum board sheathing
  • Can also be used as an adhesive for installation of EPS insulation onto wood substrates such as plywood sheathing and OSB
Physical Properties
Product Type

Water based acrylic emulsion


White dense compound



Minimum Curing Temperature



1.25 -1.35 Kgs/lt

  • As an air/water-resistant barrier
  • Average 19 m2/pail (205 ft2/pail)
Substrate Requirement

Clean solid wood, preferably plywood substrate

Performance Properties
Method Results
Air Leakage


0.023 L/s.m2 @ 75 Pa differential

Water Vapour Permeance
  • ASTM E96  Method A
  • ASTM E96  Method B
  • 248 ng/Pa.s.m2 (4.3 Perms)
  • 645 ng/Pa.s.m2 (11.3 Perms)
Coefficient of Water Absorption

CCMC Method 5.5.1

  • 0.0012 kg/(m².s1/2) on cement board
  • 0.0010 kg/(m².s1/2) on OSB
Adhesion (axial pull)

ASTM D1623

                  Cement      Concrete     Glass Mat    Wood

                   Board                               Gypsum     (OSB)

Dry State   Pass              Pass             Pass           Pass

2h- dry       Pass              Pass             Pass           Pass

7 d- dry      Pass              Pass             Pass           Pass