UPDATED on September 7, 2017 with a new postscript.
In the fall of 2012, I tested the performance of 11 air-sealing tapes by attaching samples to six different substrates mounted on the exterior wall of my woodshed. A month later, I tried to remove the tape samples to determine which tapes were most tenacious. I reported my findings in the April/May 2013 issue of Fine Homebuilding. (The details of the test set-up can be found in that article, “Backyard Tape Test.”)
The tape samples have remained in place for almost a year. Rather than dismantling the components and throwing them away, I recently decided to see which tapes have held up best over the last 10 months.
Here’s the good news: several of the tested tapes are still remarkably tenacious. In fact, a few tapes even seem to have gotten more tenacious as time has passed.
Peeling back the tapes
After trimming the flapping edges of all of the tape samples that hadn’t blown away in the wind, I repeated the tenacity tests that I originally performed in October 2012.
As I wrote in the original article, “I peeled back about 3 inches of each tape to judge its tenacity. Some samples were so tightly attached that it was impossible to pull them back that far. The ratings given in my test report are based on my own judgment of tenacity. … I didn’t use any tools other than my eyes and my bare hands, so this backyard test makes no claims to scientific validity. I rated a tape highly if it was difficult to peel back. … While it seems logical to me to favor tenacious tapes over tapes that don’t hold very well, I’ll leave it to readers to judge whether my criterion was valid.”
The best-performing tapes — the ones that I rated excellent and describe as “still tenacious” — were very difficult to peel back. On some substrates — especially the foil-faced polyiso, the housewrap, and the polyethylene — the best tapes were so tenacious that the substrates were damaged by my attempts to remove the tape.
Which are the best tapes?
Three of the most impressive tapes were Siga Sicrall, Siga Wigluv, and 3M All Weather Flashing Tape. Siga Sicrall was the best-performing tape on XPS.
Siga Wigluv and 3M All Weather flashing tape clung tenaciously for 10 months to both plywood and OSB.
Which tapes were the most disappointing?
Just because a tape does well on one substrate doesn’t mean it will work well on another. For example, Zip System tape performed well on housewrap, but it fell off the XPS at some point during the last 10 months. So don’t use Zip System tape on XPS.
Dow Weathermate tape also fell off the XPS. Pro Clima Tescon No. 1 tape stayed in place on the XPS, but it was still disappointing; it came off very easily.
On plywood, Dow Weathermate and Venture 1585 CW-P2 did worse than all the other tested tapes. Venture 1585 CW-P2 was the worst performing of the tested tapes on housewrap.
A summary of the latest results
OSB. Two tapes performed very well on OSB: Siga Wigluv and 3M All Weather Flashing tape.
Plywood. Five tapes all did very well on plywood: 3M All Weather tape, Zip System, Siga Wigluv, Siga Sicrall, and Pro Clima Tescon No. 1.
Polyethylene. Four tapes performed very well on polyethylene: Polyken Shadowlastic, Siga Wigluv, Siga Sicrall, and Pro Clima Tescon No. 1.
XPS. This test taught me that XPS is one of the hardest substrates to tape; it’s even harder to tape than OSB. The best of the tested tapes on XPS was Siga Sicrall. (Note, however, that the manufacturer of Siga Sicrall recommends the tape for interior use only. The best-performing exterior-rated tape on XPS was Siga Wigluv.)
Foil-faced polyisocyanurate. Foil-faced polyiso is very easy to tape; almost any decent tape will work.
Housewrap. Most of the tested tapes performed well on housewrap.
Still getting stronger?
Some tapes that didn’t seem particularly tenacious after a month fared better after 10 months had passed. Tapes in this category include Pro Clima Tescon No. 1, 3M All Weather tape, and Zip System on OSB; Venture 1585 HT on housewrap; and Pro Clima Tescon No. 1 on polyethylene.
The apparent reason for this finding: the bond created by a high-quality acrylic adhesive is slow to develop. Tapes in this category may get more tenacious as time passes.
|Substrate||Tapes worth considering||Tapes to avoid|
|OSB||The four tested tapes were all still in place after 10 months. From the most tenacious to the least: Siga Wigluv, 3M All Weather tape, Zip System, and Pro Clima Tescon No. 1.||All four tested tapes were acceptable.|
|Plywood||Five tested tapes were still tenacious after 10 months: 3M All Weather Flashing tape; Zip System tape; Siga Wigluv; Siga Sicrall; and Pro Clima Tescon No. 1.||Two tested tapes were significantly worse than the others: Dow Weathermate and Venture 1585 CW-P2.|
|Polyethylene||Four tapes were most tenacious: Polyken Shadowlastic; Siga Wigluv; Siga Sicrall; and Pro Clima Tescon No. 1. The other two tested tapes — Venture 1585 HT/W and Dow Weathermate — were very good, but not quite as good as the four best tapes.||All of the tested tapes were acceptable.|
|XPS||Siga Sicrall was the winner; it held well after one year. Siga Wigluv and 3M All Weather Flashing tape still held, but were not as tenacious as Siga Sicrall.||Pro Clima Tescon No. 1 and Polyken Shadowlastic tape barely stayed on. Zip System tape and Dow Weathermate both fell off.|
|Foil-faced polyisocyanurate||Most tested tapes were still tenacious after 10 months: Siga Wigluv, Siga Sicrall, Pro Clima Tescon No. 1, Dow Weathermate, Polyken Shadowlastic, Nashua waterproofing repair tape, and Venture 1520 CW foil tape.||Venture 1585 CW-P2 was noticeably less tenacious than all the other tested tapes.|
|Housewrap||Four tested tapes were tenacious: 3M All Weather tape; Zip System; Siga Sicrall; and Venture 1585 HT.||Two tested tapes did not perform very well: Dow Weathermate (fair) and Venture 1585 CW-P2 (poor).|
A GBA reader named Tom Cross posted a comment on tape tenacity on one of the Q&A pages on September 7, 2017. (Caveat: Cross’s information has not been independently verified.)
Cross wrote, “I took two pieces of OSB and put both 3M 8067 and Zip tape on the seam and left it outside for a month. Both stuck well, with Zip tape being superior. The key is to roll the tapes very well to promote adhesion. Then I read the literature on 3M 8067 and found that 3M 90 contact adhesive is recommended to improve adhesion to marginal substrates. I repeated the test using 3M 90 under both tapes. Adhesion improved dramatically. Zip tape was again superior. I repeated the test over concrete and the Zip tape/3M 90 was the clear winner.
“I ended up using Zip sheathing rather than OSB/housewrap and Zip tape for the joints. But I did use the 3 ¾ inch Zip tape/3M 90 on the Zip sheathing/poured concrete wall joint with terrific results; no failure anywhere after two months of weather exposure.”
Martin Holladay’s previous blog: “Fukushima and Vermont Yankee.”