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Community and Q&A

Exposed Wigluv tape

user-1135248 | Posted in Green Products and Materials on

The spec sheet for Siga Wigluv tape claims that it is “UV stable”. Does
this imply that it’s appropriate for little seal-up jobs on the exterior?
There are a couple of funky end-cap joints on my metal roof which could
let water in if windblown rain arrives horizontally, and I’m thinking
a slap of Wigluv over the slots would be an acceptable fix if it’s
likely to last more than a couple of years under sun exposure.

Or are any of these products too new to really know? Did any of the
Siga offerings make it into the “backyard tape test”?


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  1. DIYJester | | #1

    Have you tried peel and stick flashing?

  2. Expert Member

    Isn't your metal roof only a couple of years old? They should be detailed to last without leaks for decades. Relying on membrane fixes seems like the wrong approach.

  3. DIYJester | | #3

    I misread the original post, why do you need something exposed? The flashing should be done correctly to prevent this and beneath the flashing is usually peel and stick in areas where leaks are more likely to happen.

  4. user-1135248 | | #4

    Idealism lost out to contractor reality in this case, and the ridgeline
    joints over the shed-dormer split are a little hokey:

    The roofer did try to re-bend things a little better on his finish-up
    visit but it's still not great, so I just want a little better seal
    across the top of that small area. A strip of Wigluv is wide enough
    and flexible enough to do it, I'm figuring. A quick squirt of silver
    paint could help hide it and possibly even more UV-resistant.

    I'm pretty confident about the rest of the job, but specific details
    like this always have to be fabbed up on-site and that's where some
    weirdness can creep in. I've already added extra caps over the other
    ridgeline joints because they weren't originally overlapped enough.


  5. Expert Member

    It looks like the cap is held with stitch fasteners into a Z closure strip. I would undo a few and then bend up the lower cap in a triangular shape so it is overlapped by the upper bend your roofer attempted. Neither what I'm suggesting ,or what your roofer did is how that intersection should be flashed, but it's better than relying on a membrane.

  6. GBA Editor
    Martin Holladay | | #6

    1. The product you are looking for is called foil-faced butyl tape. There are several brands; here is a link to one product:

    2. Yes, Siga Wigluv was tested in my backyard tape test. Here is a link to one of my articles on the topic: Return to the Backyard Tape Test.

  7. mezay | | #7

    Regular Wigluv spec is good for 12 months UV stability. If you want "permanent" UV stability, I would use Wigluv Black.
    Full Disclosure: I am a SIGA employee based in Portland, Oregon.

  8. DIYJester | | #8

    Scott, find me somewhere I can find these products for less then 4x the competition and I'll buy it in a heart-beat.

  9. user-1135248 | | #9

    Well, the Q&D tape fix is done; details added to the end of the above
    referenced "rcap" page. I'll keep an eye on it and let y'all know how
    it holds up over time. A naked piece of Wigluv I've had over the joint
    of an outdoor light fixture for a year-plus now showed no signs of
    degradation so far, so I went ahead with this on the roof.

    Thanks for the product recommendations! If/when this fix degenerates
    and shreds itself I can try some of the others. On the Wigluv Black --
    its spec sheet still says "exposed to atmosphere for 12 months" in the
    same way as for the regular white stuff. What exactly does this mean?
    Any Wigluv installation is going to be exposed to atmosphere, unless
    you're using it to repair the space station. The "construction" text
    in the spec sheets for both is almost identical. Is there a real


  10. jackofalltrades777 | | #10


    4x the price? The hyperbole is unwarranted. SIGA tapes are a little more $$ than the competition but you get what you pay for. Maybe 30% more but no way are SIGA tapes 400% more than comparable tapes.

    Here's one right back at you:
    I guess you walk into the Mercedes Benz dealer and ask to pay for the car with what a Chevy Cavalier costs.

  11. jackofalltrades777 | | #11

    Typically SIGA tapes are covered with a cladding or finish. So on a wall it would be the siding or stucco finish. On a roof it would be the metal, asphalt or tile roof.

  12. user-1135248 | | #12

    And is there significant difference between said cladding in the
    "white" vs "black" variants? Hello, Scott Mizee, looking for what
    the supposed distinction really is.


  13. jackofalltrades777 | | #13

    Once the tape is covered with cladding it doesn't matter if you used the white vs black tape variants. The WigLuv is designed for temps up to 212F so once it's protected from the direct UV it will last the life of the building.

    What makes SIGA different than its competitors is that SIGA tapes are free from solvents, rubber, resins, VOCs, high boilers, plasticizers, chlorine and formaldehyde. The shelf-life is indefinite because there is nothing there to off-gas or break down. Other tapes have VOCs and other chemicals hence their 12-month shelf life and the product will off gas.

    Plus the SIGA tapes are vapor permeable. WigLuv has a Perm rate of >1.7

  14. DIYJester | | #14

    Peter, 30%? Please show me where I can get Siga tape for $20 a roll. I find other various construction tapes for $11-$25 a roll. I found Siga for $59.

  15. jackofalltrades777 | | #15


    If you are looking for high-performance building tapes that sell for $11 a roll then I had you figured out back in post #10. You can't even buy duct tape for $11 and you want to seal up a home with a tape that costs $11 per roll?

    If you are a builder (which I hope not) then your version of "builder grade" is below the current poor standard of "builder grade".

    Let me guess. You buy your windows at Lowe's and grab the Jeld-Wen windows for $200 a pop because why pay $350 a window when you can get a Jeld-Wen off the shelf for $200.

    We are NOT even on the same page and the same level of logic and scientific approach. If you think that $11 a roll building tapes are the best simply because they are the cheapest, then good luck to you and your builds. I hope you let your home buyers know that you installed the cheapest windows and used the cheapest priced products you can find. I am sure they will be thrilled to hear your business model and approach to quality products.

  16. DIYJester | | #16

    Peter, please show some factual evidence you have to support your comments. Until then all I can politely say is GFY.

    I hope you're not a contractor screwing working people out of their money. Let me guess you buy the Jeld wen windows and tell your client it's the best thing since sliced bread and charge them $600 for the spray foam job you did to seal the rough out.

  17. jackofalltrades777 | | #17


    It's quite apparent that you are not comprehending the discussion at hand. Your last post made absolutely no sense since you are attacking yourself in that post. My point is that QUALITY products should be used in high-performance builds and quality products cost more. That is a fact of life. If you think $11 building tape is the same quality as SIGA tapes, you don't know what you are talking about.

    I used Jeld Wen windows as a reference because the ones at Lowes/HD are basically meant for a garage or dog house, not for a high-performance home. They are inexpensive but you get what you pay for. That was my point all along. You get what you pay for. You compared SIGA tapes to $11 building tapes you found at HD. Just because it's "building tape" doesn't mean it's the best quality and not all tapes are created equal, especially ones that cost $11 per roll. Apparently that point went over your head so I will leave it at that.

  18. GBA Editor
    Martin Holladay | | #18

    Peter and Michael,
    It's perfectly OK to say that you prefer $11 tape to $59 tape. It's also perfectly OK to say that Siga Wigluv is a high-quality tape that is worth every penny of its retail price.

    However, it's not OK to insult people who post comments on this web site. Personal attacks will not be tolerated. We're here to discuss building science issues, products, and construction methods. Nobody is interested in attacks on other people's character. Besides, it's rude.

  19. DIYJester | | #19

    Did you actually read my posts? I never questioned the quality of the tape at any point, just it's cost.

  20. STEPHEN SHEEHY | | #20

    For whatever it's worth, I paid about $1.00 per square foot for 3M 8067 flashing tape (2" wide x 75 foot roll for 12.50 per roll) and about $2.70 per square foot for Wigluv 100 (3.9" wide x 82 foot roll for 69.15). I used a lot of both and would use them again.

  21. Expert Member
    MALCOLM TAYLOR | | #21

    Did you find 2" an adequate width for sealing? If so the Wigluv becomes even more expensive than the square foot comparison suggests.

  22. DIYJester | | #22

    Malcolm, do you mean 2" on both sides of the seam or 2" total.

    Stephen, how long ago did you do all the taping? I'm interested in long term performance due to the possibility of shrinkage of the xps and loosing my air seal.

  23. STEPHEN SHEEHY | | #23

    Malcolm and Michael:
    We used the 2" 3M tape for sealing the sheathing (advantech) joints as well as house wrap seams, as well as a bunch of other stuff like RamBoard we used for protecting the poished concrete floors.
    We used various widths of Wigluv to flash windows and doors. We used other Siga tape to seam Majpell membrane. In a few cases, both tapes ended up exposed to the elements for several months. Both stay stuck tenaciously. We used lot more 3M than Siga, but for the most critical window and door flashing, the Siga tape seemed most appropriate. In addition, using the Siga tapes for seaming the Siga membrane to avoid any possible compatibility issues.

    As far as I'm concerned, both products are great.

    You can get Wigluv in several widths, including 60mm, which is a little more than 2".

  24. Expert Member
    MALCOLM TAYLOR | | #24

    Thanks Stephen, That's great to know.

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