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Testing Flashing Tapes

Builders have a love/hate relationship Peel & Stick tapes.  We love that they solve problems, but they can frustrate the heck out of us when they do the dreaded “Stick & Peel”.  I can’t tell you how many times over the years that I’ve seen tapes used on the job that have peeled off the wall the day after installation.  If that’s your experience you’ll enjoy this Univeristy of Texas Construction Durability Lab study of tapes and flashings that are commonly used for weatherizing on the job.  They tested a bunch of different brands of tapes and used them on several common substrates including: OSB (both sides), Plywood, Huber Zip Sheathing (an enhanced OSB with a green WRB weather resistive barrier attached to the face), Exterior Gypsum, and Exterior Rigid Foam.  Before we get into the testing results let’s talk about the types of tapes.

There are three common categories that these tapes fall under.

  1.  Modified Asphalt based.  These have been on the market since the 1970’s.  This is the least cost tape in the test and the adhesive is tar-based.  Because it’s oil-based it can be prone to liquefaction with high temperatures (I’ve seen black oily runs onto metal window head flashing because of this), and you need to be careful with compatibility as the petroleum can eat through some caulks, sealants, and even some WRB’s.   This category has the least “tenacious stickiness” (would be a great band name) and really needs to be pinned-down in order to make it really hold fast to the building.  I’ve found that this tape really needs a primer in order to stick it to common building materials, and you’ll want to consider physically attaching the top of the tape to the building too.  I often use primer plus cap fasteners to attach this type of tape.  Examples of this type of tape are FortiFlash, Carlisle CCW 705, PolyWall AlumaFlash Plus and most of the common “Flashing Tapes” you see sold at the Home Center for window installs.

    Not unusual to see a peel & stick falling off a house.  No primer used here, and it looks like it fell off the OSB quickly after application.
  2. Butyl based.  This is a newer generation of adhesive that hit the market in the 1990’s.  This adhesive is much more compatible with other caulks/sealants and does well in high temperatures plus sticks at lower temps than Asphalt.  Butyl sticks to common building materials, but you’ll want to use a primer for the harder substrates like OSB or Plywood in order to ensure it stays adhered.  Common examples of Butyl Based flashing tapes include Dorkin Flashing Tape, DuPont Straightflash, and FortiFlash Butyl.  This is usually a more expensive tape and I find that it’s not usually stocked at Home Centers but you’ll find it at specialty lumber dealers and waterproofing supply houses.  Most flashing tapes that are Butyl based will tell you on the package that it’s Butyl.

3.  Acrylic based.  This is the newest generation of adhesive technology that’s been in the marketplace for roughly 10-15 years now.  As you’ll see in the video the tapes based on this adhesive did the best overall with stickiness.  Common examples are Huber Zip Tape, Delta Multi-Band Tape or Delta Fassade S Tape.

Test rack showing tapes in tension with a small weight attached to see how well they stick given stress. It’s no accident that most of these on the rack are acrylic based as the Asphaltic & Butyl based tapes have fallen off already.

This test has a full white paper coming out this Fall but here’s my general take-away after visiting the test facility. ( Look at this link to see if the paper has been added and see the results of other testing they have done. )

  • The top tapes in the test were Dorkin’s Delta Fassade S and Huber Zip tape.  Both of these tapes are acrylic based and when used with a substrate that’s made for acrylic tape (Huber Zip Sheathing) these tapes did extremely well.
  • They need to be applied under the right conditions and they need a J-Roller to really hold them fast but once they are applied well they are going to stay adhered a LONG time.
  • Both of these tapes were able to hold the weight without failure for the duration of the testing (roughly 30 days).  Many of the other tapes failed in minutes or hours.   The green WRB face on the Zip Sheathing is specifically designed as an ideal substrate for their acrylic based Zip Tape and that combo is really good!
  • I think another big take-away from this testing is that each of these three types of tapes have their place on the jobsite but a builder needs to know their deficiencies and how to use them properly.  For instance, Asphaltic peel & sticks can be very useful but they take careful prep/install to work properly.


Matt Risinger

Risinger & Co

Austin, TX