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Liquid Flashing Not Curing

Ryan_SLC | Posted in General Questions on

My liquid window flashing that cures in 6hrs isn’t curred 2 days later. Help ideas?

Hey all,

I used Benjamin Obdyke HydroFlash LA around four of my rough openings 2 days ago. I applied it perfectly from 20-30 mils. I applied it in great weather conditions. It’s still as liquied and tacky if out of the sausage while I was applying it. The tech sheet says it’s moisture cured. Salt Lake City where I am at is extremely dry right now, so I’ve misted the flashing pretty good but with no results. I cannot say if any area has cured more than any other area.

I’ve called Benjamin Obdyke and emailed, but they are closed until tomorrow. As I’m in Salt Lake, I’m running up against time to get my project finished asap for winter and today was a free weekend window setting day. If it’s a bad batch, I can’t even imagine the trouble I am in for getting it off. I think I’m looking at a total disaster clean up if this stuff doesn’t cure. I am hopeful someone has a great idea.

Has anyone experienced a non curing liquid flashing and have ideas to cure it? While wait to talk to them is obvious, the clock for working hours is falling to pieces against me and I just sank a weekend day for windows in–huge problem for me.

Thanks all

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  1. Expert Member
    Akos | | #1

    My guess is cold temperature. Put a space heater against one of the areas, if it cures properly the material is fine, it will just take much longer.

    P.S. Watch with big propane/kerosene space heaters against windows, if it gets too hot, the IGU can crack.

  2. Ryan_SLC | | #2

    Application temp range is 25-100 degrees on the spec sheet.

    Last two days have been 52, 54, and today is 60.

    I'll try the heater though. I'm desperate.

  3. Ryan_SLC | | #3

    Welp the heat actually made it more liquid.

    Unless they have a solution, i am completely in trouble. The goo is on framing, sheathing, and house wrap. The smell is still strong.

    I am defeated and my addition is ruined

  4. steve41 | | #4

    Sorry to hear this Ryan. If you have truly met all of the installation specs and the product is still liquid after 48 hours, then it's seems plausible that you have bad product.

    Hang in there - it's fixable. Maybe start a side project: test a little bit of the suspect product, scrape it off after it doesn't cure for a while and then try a similar product over it.... Prosoco fast flash, Zip liquid flash, etc. Basically start a plan B.

    I took a quick look - Zip liquid flashing has an min. installation tempurature of 35F.

    Good luck.

  5. Ryan_SLC | | #5

    How to remove an off gasing liquid goo though.

    Time and likelyhood i am destroying everything with intense water and soap scrubbing. 6 sausages is a ton of weight of product. Where will that end up?

    I did the whole rough 2x6s. That means off gasing will be interior too.
    It is on the sheathing 3 inches and under their house wrap.

    Oh my gosh i am hosed.

  6. Patrick_OSullivan | | #6

    Feels like a bit of a watched pot situation. Let it be for a bit.

    1. Ryan_SLC | | #7

      I dont know. I mean nothing to know untell i hear back tomorrow.

      I cant say if any parts are any better between the two days or heading towards cured. Even where i went too thin on the most interior of the sills touching is leaving finger prints.

      Thank you for the ideas and hope

      1. Patrick_OSullivan | | #8

        Fingerprints don't surprise me. If you touch it and it sticks to your finger instead of the surface (after sufficient time), then you have an issue.

  7. Ryan_SLC | | #9

    Uh oh. I have an issue based on that. I do have lift off

    1. Patrick_OSullivan | | #12

      Note that I said after a sufficient period of time. In your dry conditions and relatively low temperature, I'm not convinced it's been enough time.

      1. Ryan_SLC | | #18

        Totally get you now. Yes. Here's hoping.

  8. Expert Member
    Akos | | #10

    Sounds like you got an expired batch. Check the date code on the tube to see. If indeed expired, your are SOL, you'll have to clean it all off, wash it off mineral spirits and start again.

    This has happened to me once with some old stock I grabbed at a random hardware store, was not fun.

    1. Patrick_OSullivan | | #13

      Genuinely surprised if this is the case. My experience with these products is when they "go bad" they cure in the packaging, not enter some state of purgatory where they never cure.

      1. Expert Member
        Akos | | #15

        I don't know much about the STPU chemistry of HydroFlash, you are probably right since most PU stuff hardens solid over time. The stuff that did not cure in my case when expired was silicone (I think it was acetoxy cure).

        1. Ryan_SLC | | #19

          Is mineral spirits the likely solution if I'm hosed?

          Where I put it on everything, I just fearing what that will do to the sheathing, framing, wrb....

          I can't even fathom how long that would take and how unlikely it would be to get it all off.

  9. Ryan_SLC | | #11

    BO only sells from one place. Cant guess their stamp code but will post it later

  10. kyle_r | | #14

    Try taking a spray bottle of water and misting a test section to see if it cures

    1. Ryan_SLC | | #16

      Hey Kyle. I tried misting all the window liquid flashed areas 3 times now because the spec sheet says it's moisture cured. Definitely didn't cause a noticeable change.

      I will say, I only did that today, so the misting didn't create the problem.

  11. Ryan_SLC | | #17

    If it's extra time, I'll let everyone know. Hopefully that's the case. However, best case this has set me back a lot of time. I don't even want to consider that my Prosoco Joint filler I put on the foundation sill cured as expected just a week ago in similar climate.

    However, I purchased the 6 sausages in two separate orders with not one area currently cured with tomorrow day 3. This makes me think they have a huge problem, or hopefully, my case just needs 12xs more time than stated to cure.

    Here is one unopened sausage from the most recent batch. I cannot guess a date code in this? Regardless, BO only sells their product through, so it seems unlikely they've got old stock.

    Worst case, uncured goo like this would have to 100% come off? I can't imagine how you could tape over or ZIP/Prosoco to encase it? The smell is quite strong

  12. freyr_design | | #20

    I know this sounds a bit ridiculous but before trying to remove you might try to tent the area and introduce humidity and heat, perhaps with a humidifier, or even just a pan of water in front of heater. I have no idea how the reaction occurs but if it is humidity based perhaps this would help. I would just not want to remove LF after application. That being said mineral spirits work well to remove, but as you said may damage other components. If it is still the same as first application, scrapping should be able to remove the majority.

    1. Ryan_SLC | | #21

      Thank you for the idea

      1. freyr_design | | #27

        I don’t know if you will get any useful information, but here is a paper discussing stpu. I would read thoroughly if I was in your boat. They actually have a couple of test samples discussing poor moisture curing.

        Good luck

        1. Ryan_SLC | | #29

          Thank you!

  13. Ryan_SLC | | #22

    Hey all,

    So to apply a liquid flashing, the point is to jam it in all the knocks and crannies of the framing and sheathing. For perspective, that top header is 2x with gaps between and I was pushing the LA into some pretty deep differences.

    What am i looking at for trouble with mineral spirits as the possible clean up process? Will mineral spirits damage the OSB or framing lumber? I assume if they come back with bad news, the house wrap is just done for with no way mineral spirits wouldn't destroy it or successfully take it off.

    Permanent smell just can't be accepted, so that's the major concern.

    1. Patrick_OSullivan | | #23

      If it came to that (and I don't think it will), I wouldn't even try to remove it. I'd be trying to cover it with something.

      Side note... the amount of blue splotches on adjacent materials and the ladder is why I think liquid flashing entire ROs is more trouble than it's worth and why I prefer tape.

      1. Ryan_SLC | | #24

        The covering it up part is fine. I'd waste all amounts of tape to cover it up and move on with life. It's the idea that whatever covers it up, would the smell penetrate through? If the answer is to just tape over it, I'd consider that great. Shoot, we will consider this best "belt and suspenders" window weather proofing in history. If I could confirm the smell would be contained, I would buy another roll of their 9" like I have now and go to freaking town on covering it up.

        But I couldn't allow any amount of that smell to exist after. It's pretty strong. So that is my major concern for clean up right now. Just planning ahead if it's bad news.

        To be fair, I did ask if the pros always using painters tape was just to impress home owners or if it served a purpose. When I heard here it serves no purpose and the point is to put it on, I might have been pretty carefree in just getting it on. Below the ladder is my central air unit. So this wall is extremely difficult to work on. Those splotches are my gloved fingers clinging to a flat surface as I tried not to die :D

        Attached second picture where I didn't use my sausage gun after losing the nut. I just cut the sausage and dabbed. That was a disaster of my own making, but still it turned out fine.

        Yes. It was a mess for sure. The ladder did have it on because my sausage gun got messy and I had no place to put it on. I successfully did not get any on me though in a tshirt.

        I say the mess would be worth it...if it freaking sets up...

        1. Ryan_SLC | | #30

          If anyone is questioning that middle band of wrap...I stupidly went from right to left without noticing the corners are not the same height. So the extra layer was correcting that moment where I swore at myself for not thinking that out :D

  14. Ryan_SLC | | #25

    Want you all to know I'm super appreciative of the help and ideas.

    I will say, I have Tyvek on the other wall as you can see and I ripped off the GC's Everbilt wrap. Of those three, the BO flat wrap seems to be the best stuff. Cut easy but was the most substantial. Laid really flat. Their tape is my favorite out of the 3M, Zip, and Siga that I also used.

    I'm not throwing BO under the bus, but I'm not exactly in a good spot with this LA.

    1. Expert Member
      Michael Maines | | #26

      Have you heard from them yet this morning? I would call them every half hour until you get hold of someone in the technical department. I'm sure you're not the first one to deal with this issue.

      1. Ryan_SLC | | #28

        They emailed back asking about temps of the product and application temps.

        Both were in their stated range. Waiting to hear back next.

        1. andy_ | | #33

          I haven't used that specific product, but in my experience sometimes applications that are closer to the outer edges of the stated range to apply just take a little longer to cure. Add in the fact that there seems to be a lot of this stuff applied and that you live there, and well...this might not have been even noticed by most of us on a job site where we'd only be coming back to it today. Take a deep breath (away from the product and any potential off gassing) and check back in with OB tech support for a solution or a reality check on cure time for your conditions.

          1. Ryan_SLC | | #34

            You and others who have said give it time might be right. I'm not discounting that at all. It's definitely what I want as I selected the product as it appears great.

            That darn 4-6hr cure time on the sheet, good to apply when went wet...but no mention of days to cure in dry has me worried.

            In the end, I'll be happy for it to dry and a asterick is added to the install sheet for that once ever Ryan_SLC problem of super dry climate issue :D

  15. steve41 | | #31

    Just throwing out ideas:

    If your concern is smell/off-gassing, perhaps make a sample board- coat it with your non-curing product, wait a bit, then coat over it with another product and see what the results are for curing and smell.

    Maybe make a few the samples using the same product in varying, and more controlled, temp/humidity conditions.

    Maybe make samples and do some test clean-up with various approaches.

    The product manufacturer may be super responsive and have recommendations or they may be slow to respond and not have much to offer. I'd be doing a little experimenting in parallel.

    1. Ryan_SLC | | #32

      Not a terrible idea at all.

  16. Ryan_SLC | | #35

    K. Benjamin Obdyke has been pretty responsive.

    It's a wait suggestion. My area is 15% humidity and they want 60% for cure time. The exponential increase from 6hrs to days with not a single area curing has me concerned, but I'm also not wishing ill will on my project and otherwise their house wrap and tape have behaved better than others.

    I'll keep misting and keep positive hope alive.

  17. steve41 | | #36

    Just curious- any curing yet? It's been ~2 days since your original post, so 4 days total since you applied the liquid flashing.

    1. Ryan_SLC | | #37

      I'm feeling like we're heading in the right direction, but still having lift off.

      Of course I lost my mil guage while handling all this stuff on a ladder. I have a new one from Amazon coming tomorrow and I'm going to re validate areas that have lift off.

      I'm pretty sure I'm well within 20-40 mils on all of it but a few areas that I accept are more.

      I'm misting like crazy and also soaking the framing bit.

      Once misted, it acts like you'd expect and the water makes it 100% slick. I'm focusing on keeping it wet instead of even checking right now.

      Later today, I'll approach it with dread to test.

  18. Ryan_SLC | | #38

    Day five update.

    The liquid flashing was as wet on Saturday as when I applied it Friday. I could move it as easily the next day as when it first left the sausage package. That seemed true on Sunday as well.

    Today, Tuesday or day 5, I think if I look back to were it was at Friday, the area has changed from completely wet to now extremely tacky boarding on still kinda wet when pushing hard.

    I don't feel like this is necessarily success, but I do think there has been a change. I don't know if that change should be expected to continue or not.

    I will say not one area is not extremely tacky, regardless of thickness. This might be normal, but it does feel boarding wet too.

    Thank you everyone. I'll keep misting and hope that is doing something.

    1. tim_william | | #39

      I've been following this thread, good luck! This is a horror story.

      1. Ryan_SLC | | #40

        Thank you. I know. I feel the same way when that non curing spray foam thread pops to the front page. Absolutely sick to think of that poor person.

        I think tomorrow will be the day. The second mil gauge comes in, it will be three days of misting..if there are areas clearly pictured within spec but not cured, with constant daily misting and days beyond cure time on the spec sheet....I don't know. Not good.

        I think I've actually been pretty patient given no mention of moisture curing means untouchable days later.

  19. Ryan_SLC | | #41

    Benjamin Obdyke said they had never heard of this before, which is a little upsetting because, welp, you have now.

    I contacted Prosoco on their FastFlash, both being STPU products. Prosoco responded very fast with technical information. For their STPU FastFlash, they would expect longer cure for less than 70 degree weather and my 15% humidity too. Prosoco did say they basically would not expect their STPU to never not cure. So that gives me hope that this is just the perfect storm of lack of normal cure. Hopefully that it didn't cure fast in itself isn't a problem for long term.

    Waiting on the mil gauge to come to even touch it today, but will update with lots of pics. I can't even bring myself to touch it yet.

    Thanks all

  20. steve41 | | #42

    Good luck Ryan. I'm curious about the mil gauge- is there a reason to suspect the thickness of the applied product has changed?... or are you just looking to verify thickness?

    1. Ryan_SLC | | #43

      I mil gauged a few times just to get an understanding of what 20-40 mils is and then went from there.

      I think it's fair if I have lift off from an area that is within spec....not my fault at that point.

      I do want to defend myself and not just say it's thickness I applied

  21. steve41 | | #44

    Ryan- did it cure?

  22. Uiloco | | #45

    Try increasing humidity around the flashing and cover it with plastic. Check the tech sheet for curing temperature info. Also, consider using a heat gun carefully.

  23. Ryan_SLC | | #46

    Hey all,

    Thank you for the help and thoughts through this all. What an ordeal and lots of writing and responses. I have contacted Benjamin Obdyke and Prosoco multiple times through it all...but mostly leaned on you all for help and support. Thank you!!!

    As of Saturday, 8 days, we have 100% cure on the Benjamin Obdyke HydroFlash LA. No point in mil gauging pictures, the entire product just didn't cure right no matter the thickness until day 8--in my conditions. I do take issue with that as non trade person. That set me back during crunch time against weather and the spec sheet proves no help or call out for this being a thing. For example, I have no idea if the long cure hurts the product or not. Does it? I can't say.

    I misspoke originally that I had done 4 window roughs. I had done three in the blue liquid flash.

    I left one large window rough open for the spray foam crew. The spray foam was finished on Friday. On the last window rough I'll be using Prosoco FastFlash--bought off amazon, shipped fast directly from Prosoco. After this, windows go in.

    At this point, I am bugged.
    It's not that I do not recommend Benjamin Obdyke. That's not it at all. It's my experience wasn't to spec for the HydroFlash LA and with no addendum that pointed me to help.

    However, I do feel Benjamin Obdyke's FlatWrap acted like more like Tyvek Commerical I had a sample of--so I am ranking their FlatWrap as superior to my Tyvek and Everbilt house wrap for my project. I did tear off the Everbilt from the General Contractor and used Tyvek House Wrap on two adjoining peaks when I ran out of the Odbyke FlatWrap. Flat wrap felt significant and laid flat.

    Additionally, Benjamin Obdyke's tape has applied and been a larger pain when I need to lift it vs Zip, 3m All Weather, and Siga Fintrem--all of which I used a roll of for this addition. It has a perm rating too. I rank their tape as superior against even the title weight holder Siga for stickiness.

    I do recommend Benjamin Obdyke's stuff. 100%. However, I do feel like Prosoco's Join Filler cured as stated when I applied it to the foundation/sill the week before I did the HydroFlash LA. So I will be switching to Prosoco FastFlash on the last window rough and feel better about it. I will final flash my windows with Benjamin Odbyke's HydroFlash UV+ tapes.

    Thank you so much all!

  24. Ryan_SLC | | #47


    Not to beat a dead horse. I applied the Prosoco FastFlash tonight to the fourth window rough opening in Utah. Same process, way higher humidity (good) but extremely colder weather (bad).

    I applied the Prosoco at 87% humidity (snowed last night) but in extremely cold 33 degree at 5 oclock at night with almost no day light.

    The Prosoco is nearly cured and is less than extreme tacky at all areas and thicknesses (I never claimed 100% mil spec at all areas). I do mean tacky, but not extreme like I experienced before. It currently is not lifting my skin until breaking my hand away from the surface. All at six hours later.

    Either there is an extreme difference in curing between the two products or the magnitude increase in higher humidity (good) overcame an extreme cold weather increase (bad) just one week later.

    On smell, I can't say if the Obdyke long cure was the cause or if Prosoco fast cure is the cause, but the Prosoco is significantly less smelly just hours later--at almost no chemical smell. If neither, the Prosoco smell is less--taking into account 1 rough opening vs the other three.

    Finally, neither took to filling deep vertical nail holes in the rough openings. I know seam/joint filler is a prosoco product, but neither Odbyke or Prosoco liquid flash went into a vertical nail hole and stayed. All four windows have nail holes that are lacking the liquid flash when I know I 100% covered the area before walking away. There is something about this liquid flash that doesn't always hold build up on a vertical area.

    There is a product difference or these products require a humidity range that just isn't called out as significantly as they should be on either.

    Thanks all

  25. stamant | | #48

    i am spit balling, but maybe the substrate was too dry. if you had wetted the sheathing and the lumber first, then the moisture would be available from the underside of the liquid membrane. as is, spritzing the surface would not get more moisture where it would do the most good, especially if the product exposed to air skins over.

    regarding the sag at nail holes, there may be a thicker applied compatible material that can be used -- maybe a polyurethane sealant from prosoco?

  26. Ryan_SLC | | #49

    FastFlash overnight cured 100%. Tacky now, but no area is wet, even obvious gubbers. Current temp in mid morning is 34, so I know it was unreasonably past temp per the Prosoco spec sheet.

  27. Ryan_SLC | | #50

    Welp. Applied last Benjamin Obdyke LA sausage on the exterior. The picture is 3 days after applying. It snowed during one of the 3 days with high humidity. It was within temp and thickness. While it snowed, days reached high 40s and nights were low 30s.

    Here's the outcomes. On my finger and on the slick side of their split release tape. Since it's on the split release side, you know there is no reason for me to have applied pressure, as it's not "stuck" yet. This lift off happened by just touching the back of the tape to the area.

    I now think I was being too friendly for no reason other than to be friendly online. In my specific project, this product simply failed. It did not come close to the spec sheet at 32xs the time to cure. Zero documentation on what to do and I have zero idea if the cure time does or does not hurt the product long term. The paper posted above suggests it does hurt the adhesion over time.

    Thank you all for the thoughts, ideas, and mental support as I processed if I had just destroyed my addition with this product. It sure meant a lot and I am grateful.


    1. tim_william | | #51

      Thanks for documenting all this. It's rare to get such great insight into the failure of one of these miracle products.

  28. Ryan_SLC | | #52

    Welp....the story does not end.

    I took the day off today to finalize my head flashing. Went well. I bought tons of Benjamin Obdyke UV+ tape, I really like it. It has a felt like surface before the acrylic tape like on Zip. There were times where the roll unrolls and catches the felt on the next layer and it will rip next layer felt, so I think this stuff has to always be laid flat instead of standing up on the spool. I also think you have to pick those felt junks out of the tape and not just accept small areas of the felt under the tape. Again, using 3m, Zip, and Siga I felt Benjamin Obdyke tape was the best...It stuck hard and is substantial in feel.

    But....that large rough opening I posted from Nover 16th and it's now the 27th... I put my arm against it, not fully bracing myself and it come off with liquid flash on it.

    I don't think the product is meant to stay goo. Sticky? yes. Prosoco says in their advertisement that they recently updated to decrease the stickiness. So this product is inherently sticky. I get it. It shouldn't be in a state of goo though.

    I believe in the concept of the product. I do. This will 100% be the only rough opening window install project in my life, but I can tell liquid flashing is better than tape. It was easy to work with. When I misted it, the product becomes slicker than water itself. It's an odd thing to happen, but it's true. But, I just am the 1 in ever case where it's simply not curing. Hope it cures under the tape, because that's where it lives for the next forever.

    With that, I've officially buried the liquid flashing under tape flashing and life will move on.

    Thanks all.

    Fin. :)

  29. Ryan_SLC | | #53

    Not done. Dang it. was great to work with on the actual purchase. They were able to refund the liquid flashing.

    Unfortunately, I've got significant smell from the liquid flashing that is still very present this far along. Leaving windows open isn't curing the smell away. It's not like noxious, but it isn't pleasant either. MSD sheet calls it mild. I would not call it "mild." It's persistently heavy in the air. It's not burning my lungs, but heavy in the air, that's "strong" in my book.

    With no amount of reason to believe this will work, I started taping the liquid flashing on the interior. My hope is that will be an additional burial level to also include the sheet rock. Perhaps I should have gone with Zip tape because it's not perm rated. I don't know.

    If this doesn't work, my next idea is to Prosoco FastFlash over the tape. The 4th window with the FastFlash is not releasing a smell at this point. Pictured with red.

    After installing the windows, I didn't want to try mineral spirits to remove on the interior because I'm not sure how much unseen damage I would be doing to the liquid flashing behind the window. Liquid flashing the entire rough opening even past the window does seems to be the gold standard, so I don't want to disrupt what's there.

    The idea of razor blading it off also came to mind, but I don't think that would be 100% effect anyways.

    Here's hoping the tape encapsulates the smell. Entire roll of tape to tape in interior.

  30. Ryan_SLC | | #54

    If anyone in the future comes across a similar issue, in my case, taping the interior HydroFlash LA with HydroFlash UV+ did in fact stop the smell. Smell that has been for weeks and weeks is now greatly decreased from one night of doing to returning to the room to finish up the window work. I might even do it to the Prosoco FastFlash just to encapsulate any smell, but that product is now basically smell-less.

    I also sealed my windows up. Prosoco Air Dam was awesome to work with on sealing the interior to the first inserted backer rod. Worked like a charm and was a super satisfying consistency in the sausage gun.

    Thanks for all the help

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