PERM-A-BARRIER® Wall Flashing Data Sheet

Self-adhesive, rubberized asphalt/polyethylene through-wall flashing for cavity wall applications

Product Description

PERM-A-BARRIER® wall membranes are ideal for protecting the building superstructure from the damaging effects of the elements. By minimizing air and water vapor flow through the building exterior, PERM-A-BARRIER® wall membranes:

  • Prevent premature deterioration of the building envelope
  • Enhance thermal performance of the structure and save energy costs
  • Improve comfort for the building occupant

Product Advantages

  • Fully bonded—continuous adhesion to the substrate resists wind loads and prevents water tracking behind the flashing
  • Waterproof and impermeable to moisture— impermeable to the passage of liquid water and water vapor
  • Cross laminated film—provides dimensional stability, high tear strength, puncture and impact resistance
  • Cold applied—no flame hazard; self-adhesive overlaps ensure continuity
  • Flexible—accommodates minor settlement and shrinkage movement
  • Controlled thickness—factory made sheet ensures constant, non-variable site application
  • Aggressive, conformable adhesive—creates watertight laps and seals around mechanical fasteners that are properly installed through the flashing
  • Unique green color and logo—highly differentiated on the job site from other flashing types and enables easy identification of damage
  • RIPCORD® Split Release on Demand—ease of membrane positioning in detailed areas, allows for sections of release liner to remain in place to protect the adhesive
  • Foldless release paper—fewer edge catches, 180° pull-back, ease of membrane cutting (single cuts) and membrane positioning, quicker one-man installs

System Components

  • PERM-A-BARRIER® Wall Flashing— 40 mil (1 mm) total thickness self-adhesive, cold applied tape consisting of 32 mils (0.8 mm) of rubberized asphalt integrally bonded to a 8 mil (0.2 mm) high density, cross laminated polyethylene film. The rolls are interwound with disposable silicone-coated release sheet.
  • PERM-A-BARRIER® Adhesive Primer— primer for use with PERM-A-BARRIER® Wall Flashing on typical substrates such as steel shelf angles, exterior gypsum sheathing, plywood, and cured cementitous substrates.
  • PERM-A-BARRIER® WB Primer— water-based primer for use with PERM-A-BARRIER® Wall Flashing on typical substrates such as steel shelf angles, exterior gypsum sheathing, plywood, and cured cementitous substrates.
  • PERM-A-BARRIER® Universal Flashing & Sealant - one part moisture curing, STPE sealant for sealing penetrations, terminations, brick ties, final terminations & flashing application.
  • BITUTHENE® Mastic Trowel Grade— rubberized asphalt mastic for sealing patches, terminations, brick ties, etc.
  • BITUTHENE® Liquid Membrane— two component, trowel grade, asphalt modified urethane for sealing patches, terminations, brick ties, etc.



PERM-A-BARRIER® products must be handled properly. Vapors from the mastic and solvent-based primer are harmful and flammable. For these products, the best available information on safe handling, storage, personal protection, health and environmental considerations has been gathered. Refer to product label and SDS (Safety Data Sheet) before use. All users should acquaint themselves with this information prior to working with the material. Carefully read detailed precaution statements on the product labels and SDS before use. SDS can be obtained from our web site at or by contacting us toll free at 866-333-3SBM (3726).

Preparatory Work

Apply PERM-A-BARRIER® Wall Flashing and accessories only in fair weather when air and surface temperatures are above 25 °F (-4 °C).

Wherever wall flashing is to be applied, the surface must be smooth, clean, dry and free of voids, spalled areas, loose substrate, loose nails, sharp protrusions or other matter that will hinder the adhesion or uniformity of the wall flashing installation. Clean loose dust or dirt from the surface by wiping with a clean dry cloth or a brush.

Conditioning and Priming

Apply PERM-A-BARRIER® Adhesive Primer by air spray, brush or roller or apply PERM-A-BARRIER® WB Primer by brush or roller. Allow the primer to dry completely before application of the flashing. Drying times may vary depending upon temperature and humidity conditions. Refer to PERM-A-BARRIER® Adhesive Primer and PERM-A-BARRIER® WB Primer product data sheet for installation recommendations and Technical Letter 2, Substrate Preparation for Application of PERM-A-BARRIER® Products to Glass-Mat Faced Gypsum Sheathing for priming requirements on specific glass-mat faced sheathing products.

Flashing Application

Pre-cut PERM-A-BARRIER® Wall Flashing to easily handled lengths. Peel release paper from roll to expose rubberized asphalt and carefully position flashing against substrate. RIPCORD®, a Split Release on Demand feature embedded in the membrane, also makes PERM-A-BARRIER® Wall Flashing easy to position in detailed areas. Press firmly into place with a steel hand roller or the back of a utility knife as soon as possible, fully adhering the flashing to the substrate to prevent water from migrating under the PERM-A-BARRIER® Wall Flashing. Form end dams at horizontal flashing terminations to prevent water entry. Overlap adjacent pieces min 2 in. (51 mm) and roll overlap with a steel hand roller. Apply a bead of Universal Flashing & Sealant, Bituthene Mastic or Bituthene Liquid Membrane  along all laps, seams, top edges, cuts, penetrations and trowel into place. When used over PERM-A-BARRIER® VPS 30 only use PERM-A-BARRIER® S100 Sealant or BITUTHENE® Liquid Membrane along all laps, seams, top edges, cuts, penetrations and trowel into place.

Lay or trim edges of PERM-A-BARRIER® Wall Flashing 1/2 in. (13 mm) back from the face of the masonry. No reglet is necessary when installing PERM-A-BARRIER® Wall Flashing to vertical surfaces. Complete installation instructions and details are available upon request. For applications onto steel angles with bolts at the surface of the angles used to attach the angles, star cut PERM-A-BARRIER® Wall Flashing at the bolts, press the flashing firmly around the bolt, and seal the bolt with Universal Flashing & Sealant, BITUTHENE® Mastic or BITUTHENE® Liquid Membrane.

If wrinkles develop, carefully cut out affected area and replace in similar procedure outlined above. The repair piece must be pressed into place with a hand roller as soon as possible to ensure continuous and intimate contact with the substrate.

All non water shedding edges must be sealed with Universal Flashing & Sealant, BITUTHENE® Liquid Membrane or BITUTHENE® Mastic.

Protection—PERM-A-BARRIER® Wall Flashing must be protected from damage from other trades or construction materials.

Storage and Handling Information

All materials must be protected from rain and physical damage. Pallets of PERM-A-BARRIER® Wall Flashing must not be double stacked on the job site. Provide cover on top and all sides, allowing for adequate ventilation. Store membrane where temperatures will not exceed 90 °F (32 °C) for extended periods. All products must be stored in a dry area away from high heat, flames or sparks. Store only as much material at point of use as is required for each day’s work.


  Unit of Sale Approximate Coverage Weight Palletization
PERM-A-BARRIER® Wall Flashing        
12 in. (305 mm)
18 in. (457 mm)
24 in. (610 mm)
36 in. (914 mm)
3 rolls
2 rolls
1 roll
1 roll
75 linear ft per roll
75 linear ft per roll
75 linear ft per roll
75 linear ft per roll
22.5 lbs/roll
33.7 lbs/roll
49.7 lbs/roll
67.7 lbs/roll
25 cartons (75 rolls) per pallet
25 cartons (50 rolls) per pallet
35 cartons (35 rolls) per pallet
25 cartons (25 rolls) per pallet
BITUTHENE® Mastic—5 gal pail 1 pail approx. 120 ft2 at 60 mils 54 lbs/pail 36 pails per pallet
BITUTHENE® Mastic—30 oz tube 12 tubes approx. 30 linear ft x 1/4 in. bead 32 lbs/carton 72 cartons (864 tubes) per pallet
PERM-A-BARRIER® Universal Flashing & Sealant Sealant—29 oz. Cartridge 1 cartridge approx. 30 linear ft x 1/4 in. bead 29 oz. cartridge 10 cartridges/ carton
42 cartons/ pallet
BITUTHENE® Liquid Membrane—1.5 gal pail 1 pail approx. 200 Linear ft/gal @ 1” wide x 90 mils. 16 lbs/pail 100 pails per pallet
BITUTHENE® Liquid Membrane—4 gal pail 1 pail approx. 200 Linear ft/gal @ 1” wide x 90 mils. 44 lbs/pai 24 pails per pallet
PERM-A-BARRIER® Adhesive Primer—5 gal pail 1 pail 250-300 ft2/gal (23-28 m2/L) 43 lbs/pail 36 pails per pallet
PERM-A-BARRIER® WB Primer—5 gal pail 1 pail 250–350 ft2/gal (6–8 m2/L) 45 lbs/pail 32 pails per pallet

Physical Properties

  Typical Value Test Method
Color Green with repeated logo imprint    
Thickness 40 mil (1 mm) ASTM D3767, method A
Low temperature flexibility Unaffected at -45 ºF (-43 ºC) ASTM D1970
Tensile strength, membrane 1200 psi (8300 kPa) minimum) ASTM D412, Die C modified
Elongation, ultimate failure of rubberized asphalt 200% minimum ASTM D412
Lap adhesion at minimum application temperature 60 lbs/ft (875 N/m) width ASTM D1876 modified
Adhesion to concrete at minimum application temperature 60 lbs/ft (875 N/m) width ASTM D903
Puncture resistance, membrane 40 lbs (178 N) minimum MD
80 lbs (356 N) minimum MD
Tear resistance, initiation 13 lbs (58 N) minimum MD ASTM D1004
Tear resistance, propagation 9 lbs (40 N) minimum MD ASTM D1938
Permeance 0.05 perms (2.9 ng/m2sPa) maximum ASTM E96, method B
Water absorption 0.1% maximum ASTM D570


PERM-A-BARRIER® Wall Flashing must not be applied in areas where it will be exposed to sunlight permanently and must be covered within a reasonable amount of time, not to exceed 60 days. Refer to Technical Letter 19, Exposure Guidelines for PERM-A-BARRIER® Self-Adhered Membranes.

PERM-A-BARRIER® Wall Flashing and all other PERM-A-BARRIER® self-adhered membranes should not be applied over Universal Flashing & Sealant.


PERM-A-BARRIER® products are warranted to be free of defects in manufacture for a period of 5 years. Material will be provided at no charge to replace any defective product.

Technical Service

Support is provided by full-time technically trained GCP field sales representatives and technical service personnel, backed by a central research and development technical services staff. | North America Customer Service: +1 (877) 423 6491

We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation or suggestion is intended for any use that would infringe any patent, copyright or other third-party right.

PERM-A-BARRIER, BITUTHENE, and RIPCORD are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies, Inc. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

© Copyright 2018 GCP Applied Technologies, Inc. All rights reserved.

GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 475, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6
This document is only current as of the last updated date stated below and is valid only for use in the United States. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2024-06-21