Two Wingnuts Describe Their Backyard Tape Tests

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Two Wingnuts Describe Their Backyard Tape Tests

In tests performed by Peter Yost and Dave Gauthier, Huber’s Zip System tape outlasts Siga Wigluv and Tescon Vana

Posted on Apr 1 2016 by Martin Holladay
prime

Regular visitors to GBAGreenBuildingAdvisor.com probably know that I’m a big fan of backyard product tests. (In the past, I’ve reported on my tape tests, flexible flashing tests, and liquid-applied flashing tests.) So when I noticed that Peter Yost and Dave Gauthier would be giving a presentation titled “Sticky Business: Tape Testing, Round Two” at the BuildingEnergy 16 conference in Boston, I showed up early to make sure I got a good seat.

Peter Yost is GBA’s technical director, while Dave Gauthier is a sales representative for Atlas EPSExpanded polystyrene. Type of rigid foam insulation that, unlike extruded polystyrene (XPS), does not contain ozone-depleting HCFCs. EPS frequently has a high recycled content. Its vapor permeability is higher and its R-value lower than XPS insulation. EPS insulation is classified by type: Type I is lowest in density and strength and Type X is highest.. The two backyard scientists conducted a series of tests in Yost’s shed (christened the “Wingnut Test Facility”); from my perspective, their light-hearted approach brings just the right amount of irreverence to these research efforts.

At the conference in Boston, Yost began by providing “context and caveats.” He pointed out that this was “pro bono work” — the two friends have no funding for their research, so expenses come out of their pockets.

“Our sample size is two,” Yost said. In other words, each test included only two samples of each tested product, which is “not statistically significant.” He noted, “Our tests are limited. We are not here to recommend a tape. We are not here to say, ‘This is the product to use.’”

A partial list of the ASTM test protocols that tape manufacturers can choose from.

Lab testing vs. job-site testing

In theory, the American Society for Testing and Materials (ASTM) should, by now, have developed some testing protocols for tapes used by residential and commercial builders. They have — sort of — but the standardized tests aren't very relevant.

Yost explained that tape manufacturers can choose from “a panoply of ASTM tests. It’s like a buffet. So what do they do? Pick the test that they do best at.”

Yost had some fun comparing the laboratory procedures that ASTM specifies for tape testing to typical job-site conditions. “What are the specified lab test conditions?” Yost asked. “Every test uses a stainless-steel substrate. That’s acid-washed, polished stainless steel. The substrate has to be perfectly clean. Before the tape is applied, the substrate has to be maintained at a temperature of 70 degrees for 24 hours under conditions of controlled RH. Does that sound like a typical job site? Of course not. Job-site conditions are cold, wet, and dirty.”

The Wingnut researchers have been testing tapes for several years

At his presentation in Boston, Yost summarized the results of a first few rounds of tape testing that he and Gauthier performed in 2013 and 2014. (For more information on these early rounds of tape testing, see “Shocking Truth About Tapes Emerges from Wingnut Test Facility” and “Testing Pressure-Sensitive Tapes: Rounds Two and Three.”)

Describing these earlier (2013-2014) tests, Yost said, “We were winging it. But our tests were better than those devised by ASTM. … We tested four categories of tapes: modified bitumen tapes, butyl tapes, acrylic tapes, and silicone tapes.” The acrylic tapes performed so much better than the other tapes that Yost and Gauthier have decided to focus most of their future testing to acrylic tapes like Siga Wigluv, Tescon Vana, and Zip System tape. “When it's really cold, modified bitumen tapes sometimes can’t hold their own weight,” Yost said, “and the butyl tapes we tested don’t like low temperatures or tougher substrates. So we've narrowed our focus to only acrylic tapes.”

The latest round of testing performed by the Wingnuts included Huber Zip System tape, Pro Clima Tescon Vana tape, Siga Wigluv tape, IPG housewrap tape, and Pella butyl tape. (Yost described the IPG housewrap tape as “the red stuff.”)

Yost noted, “We were going to include 3M 8067 tape — the All Weather Flashing Tape — in the testing, but I went to three lumberyards and nobody stocked it.”

Taping the seam between window flanges and OSB

Yost and Gauthier devised a test method focusing on tapes used to bridge the gap between OSB sheathingMaterial, usually plywood or oriented strand board (OSB), but sometimes wooden boards, installed on the exterior of wall studs, rafters, or roof trusses; siding or roofing installed on the sheathing—sometimes over strapping to create a rainscreen. and window flanges. The type of OSB used for the tests was Huber Advantech. The Wingnut researchers tested tape samples on two types of window flanges: aluminum flanges and vinylCommon term for polyvinyl chloride (PVC). In chemistry, vinyl refers to a carbon-and-hydrogen group (H2C=CH–) that attaches to another functional group, such as chlorine (vinyl chloride) or acetate (vinyl acetate). flanges. The sections of window flange material were donated by window manufacturers, assuring that the tested substrates accurately reflected actual window flanges.

The two Wingnut researchers included enough samples to test half the samples under dry conditions, and half the samples under damp conditions.

Because tapes also have to bridge cracks between sheathing panels, the two Wingnuts wanted to simulate stresses that might occur when tape is subjected to repeated “bellowing” (or “fluttering”) caused by pressure differences on opposite sides of the tape.

Slots were cut in the OSB substrate used in the testing.

The Wingnuts made a series of slots in strips of OSB. These slots not only simulated cracks that needed to be bridged; the slots facilitated the introduction of water (via a spray bottle) during the testing procedure.

The test rig included 2-inch wide samples of window flange material. Tape samples bridged the seam between the OSB substrate and the window flange. Each tape sample measured 2.25 inches by 6 inches.

A closeup photo showing how the metal rod was inserted under the tape for testing. The photo shows a mockup that Peter Yost and Dave Gautier brought to the BuildingEnergy 16 conference in Boston.

The Wingnuts inserted a thin metal rod under each piece of tape being tested. Yost explained, "We chose a 3/16-inch metal rod because it did not flex perceptibly with the loading, and presumably spread the load over the entire surface area of the adhered tape."

At the end of each protruding rod, strings were tied to connect the rod to a suspended weight (a plastic soda bottle filled with 2 pounds 5 ounces of sand). The weight of the sand in the bottles was chosen to simulate 1,200 pascals of pressure difference acting on the tape samples; that’s a large force, but it was chosen to accelerate failures. “This test emulates wind loading,” Yost noted.

“We discussed the protocol with four major tape manufacturers to see if they would shoot us down,” Yost said, “But the tape manufacturers all said that our protocol was pretty good. So we had adult supervision.”

The two rows of test samples. One row of samples was kept dry, while the other was regularly misted with water.

Yost and Gauthier created two rows of samples: one row was kept dry, the other was wet. To simulate job-site moisture, the researchers “spritzed the top and bottom of the samples” by “squirting five times.” More moisture was introduced at regular intervals.

Yost explained that “Pro Clima told us that we were supposed to use a primer with Tescon Vana on OSB.” That was the only tape that need primer on the substrate.

The Wingnuts went ahead and applied primer on the OSB before adhering the Vana tape, but they probably didn’t wait long enough for the primer to cure before the tape was applied. “Conditions weren’t good — the primer was too liquid,” Yost said. “We may have screwed that up.”

Some tapes failed very quickly

“We set up the assembly on November 15, 2015. We didn’t install the weights to load the tapes until the following weekend, November 22.”

Yost noted that the IPG housewrap tape “failed miserably.” The same comment could have been applied to the Pella butyl tape, since both the IPG tape and the Pella tape pulled off the OSB substrate within a half hour of being loaded.

Moving the test rig

After three weeks of testing, the two researchers realized that the conditions in the shed were too stable — there were few big swings in temperature or humidity — so they decided to move the test to an open-sided shed. The test rig was moved on December 11 to the more exposed location — a site which proved, as hoped, to have greater variations in temperature and RH.

The soda-bottle weights were removed when the test rig was moved. The Wingnut researchers decided to reduce the weight of each soda bottle from 2 pounds 5 ounces to 1 pound. Yost explained, “The 1 pound weights simulate around 450 Pascals — 6 times greater than the expected in-use force of 75 Pascals. We went with 6 times greater than 75 pascals to ‘accelerate’ the testing but still be reasonable loading.”

The temperature changes in the open-sided shed caused the aluminum and vinyl substrates to expand and contract, while increases in relative humidity caused the OSB to swell.

On various dates in December, all of the Tescon Vana tape samples and all of the Siga Wigluv tape samples (on vinyl flanges and aluminum flanges, both wet and dry) failed.

The Wigluv samples lasted a little longer than the Tescon Vana samples. (After the Siga Wigluv pulled off the vinyl flange, it continued to adhere to the OSB.)

Zip System tape lasted the longest

The only tape that performed better than the Siga Wigluv tape was the Zip System tape, which (as of the date of the Wingnuts’ presentation) still hadn’t failed. The Zip System tape is the last holdout — it never let go.

Of course, the Tescon Vana tape might have performed better if the primer had been allowed to cure for a longer period of time before the tape was applied to the OSB. That said, the fact that Vana needs a primer would probably be considered a drawback for most builders.

Although the Wingnuts' testing protocol was imperfect, it was certainly valuable. “We feel more confident about the connection between our tests and the real world than the connection between ASTM tests and the real world,” said Yost.

Yost ended the presentation with an observation — ”Aluminum is tough to tape to” — and a piece of advice: ”You need to be using acrylic tapes.”

Why are these backyard tests necessary?

Builders need more data on tape tenacity and the longevity of tape bonds. We're just beginning to get some clues about which tapes work best.

There are a few — not nearly enough, but a few — full-time researchers looking into these questions. I'm pretty sure that John Straube has exposed some tape samples to the weather at a test location in Ontario, and Yost and Gauthier tipped their hats during their BuildingEnergy presentation to Professor David NiCastro at the University of Texas, who is testing a variety of materials by exposing them to the Texas sun.

In spite of these efforts, though, it's fair to say that, when it comes to tape research, our country's important institutions and authorities — including ASTM, tape manufacturers, universities, and government research labs — have, for the most part, let builders down. That's why many of us are taking time out of our busy days, and sometimes money out of our own pockets, to do backyard research: because almost no one else is doing it.

GBA salutes Peter Yost and Dave Gauthier. We look forward eagerly to future reports from the Wingnut Test Facility.

After this article was published, Peter Yost published a blog on the same topic: Our Real-World Flashing Tape Tests Find a Clear Winner.

Martin Holladay’s previous blog: “How to Insulate an Attic Floor.”

Click here to follow Martin Holladay on Twitter.


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Image Credits:

  1. Photo #1: Jerelyn Wilson
  2. Photo #2: Martin Holladay
  3. Images #3-#7: Peter Yost and Dave Gauthier

1.
Apr 1, 2016 11:40 AM ET

Wingnut hat
by Armando Cobo

Is hard to read this article after looking at Peter's picture... from the Red Mikey Mouse club? God Job!


2.
Apr 1, 2016 11:38 PM ET

Serious looks on their faces
by Lucy Foxworth

What gets me is that they all have such serious looks on their faces.

But still, the article is informative. I think it actually makes an argument for plywood over OSB. It's a far more tapeable substrate.


3.
Apr 2, 2016 3:32 AM ET

Response to Lucy Foxworth
by Martin Holladay

Lucy,
In many cases, including with Siga Wigluv, the tape samples failed on the vinyl and aluminum window flanges before they failed on the OSB. So when it comes to acrylic tape tenacity, the OSB substrate may not be the issue here.


4.
Apr 6, 2016 11:22 AM ET

Edited Apr 6, 2016 11:25 AM ET.

Orientation of forces?
by Derek Roff

Photo 7 indicates that the force of gravity is pulling parallel to the plane of the OSB, while photos 4, 5, and 6 seem to show gravity perpendicular to the OSB. OK, I just read the caption on photo 7. Was the orientation different only during the few seconds of spritzing with water? Was weight stressing the tape, during the spritzing?


5.
Apr 7, 2016 7:35 AM ET

Wingnut Hat
by Kohta Ueno

Hey Armando--the hat is one of these. I think it's a piece of Detroit Red Wings swag. http://hockeygods.com/system/gallery_images/1681/normal.jpg?1291329957


6.
Apr 7, 2016 8:29 AM ET

Orientation of forces?
by Peter Yost

Hi Derek -

We unload the 1-pound weights just before tipping up the OSB strips, then we spritz them front and back and then we lay the strips back down and reload the 1-pound weights.


7.
Apr 7, 2016 3:04 PM ET

Thank you, Peter
by Derek Roff

Thanks for helping me interpret what I was seeing in photo 7.


8.
Jun 13, 2016 2:12 PM ET

Product Availability
by Brian Knight

I can understand 3m 8067 not being available but surprised you found stockyards supplying European products. We order 3m tape and Tescon tapes online and are delivered very quickly.
If the primer had been allowed to develop its sticky tack, results would certainly have been different but agree messing with primer is a huge downside. I've found 8067 to be more sticky and flexible but less tolerant of long UV exposure. Based on my observations I would choose 8067 for everything except zip panel sheathing. Would love to see you add 8067 in the future to check my hunch.


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