Tapes vs Liquid Applied Compatibility Test

Kevin Spellman provides results of in-situ compatibility testing between tapes and liquid applied membranes.


https://www.greenbuildingadvisor.com/question/backyard-building-science


I have a foundation, but haven’t started into the next phase of my build. I had many questions about compatibility and suitability of products used for flashing, taping, etc. Nobody had all the answers, so I made this backyard test wall. It’s not particularly scientific, but it was informative for me, and it might be helpful to the odd person stumbling across it. It’s a 2×4 frame with cheap OSB sheathing applied, and a mock window opening. I wanted to know who stuck to who or what and how. Everything was applied as directed, allowed to cure, tapes were pressure applied as directed, etc.

My observations:

–FortiFlash flashing material is not very useful–doesn’t stick well to anything, and the liquid applied flashings don’t stick to it


–the Prosoco joint and seam filler/fast flash are interesting products. They are much tougher than I thought, stick tenaciously, and will have a part in my water and air sealing plan.


–A bead of Joint and Seam filler behind an aluminum nailing fin against OSB is immovable. Three large men were unable to budge it. Impressive. Same goes if you use it against FastFlash–amazing adhesive(and I would assume air and water tight)


–ExtoSeal Encors makes a great sill seal. It’s not going to come off. It’s thick, and would easily seal any penetrations. It’s an acrylic/butyl combo. Almost gooey in hot sun. Beats the pants off Fortiflash


–Tescon Vana and Siga Fentrim are the stickiest tapes I have ever used. It takes a herculean effort to strip them off after 24 hours. Zip tape is not far behind. Siga Wigluv is not nearly as impressive.


–Tescon Vana , Siga Fentrim and Zip tape stick very well to cured Fast Flash and Joint and Seam filler. Some say these tapes are not compatible with the fluid applied products, but they sure stuck well in my test. Long term? No idea. I am a backyard scientist with short term insights.


–Lexel does not stick to fluid applied products, nor to the tapes particularly well.


–If you have to use FastFlash over tapes for some reason, it doesn’t work well unless the tape has the felt coating like Tescon Vana or Siga Fentrim. Otherwise, it peels right off things like Zip Tape(zip says wipe with acetone first if you want it to stick), Extoseal Encors, SIga Wigluv, or the WRB, Siga Majvest.


–Siga Majvest doesn’t have near the adhesive power of any of the Siga Tapes, but does stick reasonably well. It is an adhered WRB. I wanted to test Solitex Adhero, but I could not procure a sample.

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