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One-Component Foam Kits Permeability

wt13 | Posted in General Questions on

Although at this point, I decided to go cut/cobble for my rim joist/joist cavities, I just wanted to put this out in case anyone has more insight/info/just wants to know/etc.

 I was looking at one-component foams as an alternative to two-component foam kits.  Specifically two brands – Vega Bond Insulation and Kraken.  They market what appears to be Great Stuff pro stuff to use like one would use two-component foams.  It is even applied with the typical foam gun one would use with pro foams – but with a small attachment that acts to “spray” the foam in a fanned pattern like two-component guns.

 One-component foams appear to have a mix of closed cell material (percentage in the 70s) and open cell (the rest), as compared to two-component foams which contain a greater percentage of closed cell (high 90 percent).

 So my concern was how effective these products would be for my purposes as far as perm rating.  Both advertise R-values, but say nothing about perm rating, which for me, being in zone 5, is an important question.  Both simply refer to their products as “closed cell.”

 Note – I realize that in the cut/cobble method, a one-component (“closed cell”) foam (usually Great Stuff) is used around the perimeter of the rigid foam.

 I emailed both vendors, and Vega Bond confirmed that their product is about 75% closed and 25% open, but could not confirm what the perm rating of the product is, and just recommended going about 4 inches when I spoke of being in zone 5.

 All Kraken could tell me was that their product is “closed cell,” not mentioning percentage, and that their product has an r-value of 5.66.  When I email back about how I was looking for information on the perm rating – not r-value, I received no further response.

 Just putting this info out.  I don’t know if anyone has any actual experience with these products – especially in cold climate use.  Another person made a recommendation of possibly using vapor barrier paint over the foam, but for me, at that point, it’s getting just as cumbersome as cut/cobble.

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  1. DCContrarian | | #1

    There is a product called "Foam Beak" which attaches to a can of spray foam and purportedly allows it to be sprayed in a layer like foam insulation. I have never used it but often wondered about it.

    At $13 I might give it a try.

  2. wt13 | | #2

    It's different from the Vega/Kraken attachment though. From their description, that product is only meant to widen the foam to 3 inches.

    If you look at the Kraken and/or Vega Bond stuff (it's also sold through Amazon), their attachment is much smaller. Close up pictures shows that their attachment has a really small hole with a "notch" that can be oriented to spray a vertical or horizontal fan. The coverage would end up being more akin to the how two-component foam guns spray and covers a wider area at once.

    I inquired with both, and how they do it is each can comes with a new tip attachment, and you can order additional attachments if you really need it. You can see the attachment in some pics.

  3. Expert Member
    BILL WICHERS | | #3

    I'm tempted to order a can of the Kraken procuct to try. I'm curious if it's just different colored Great Stuff, or if it's really a different product more similar to real two part spray foam. I was hoping someone would post in the other recent thread about this and have some real experience to share, but I don't think anyone did.


  4. wt13 | | #4

    Yeah, I ALMOST pulled the trigger because it was being described as "close cell" foam. I did more research and learned that one-component foams are limited in how much closed cell material can actually be in the chemistry - including Great Stuff. It appears to be a limitation of the type versus brand.

    So it appears the products (including Great Stuff) are described as closed cell because it's MOSTLY closed cell.

    So I called Vega Bond, and the person could at least answer what percentage was closed, but did not know what the PERM rating was. I called Kraken, and all they could say was what the r-value was per inch.

    In conversation, it seemed like NEITHER rep even knew what "perm rating" was. It was disappointing as I was hoping this would be a great/easy alternative to two-component kits.

    I tried to tell both how important perm rating was in cold climates. The Vega Bond guy seemed sympathetic and said he would push it up the chain. The Kraken guy couldn't care less.

    I don't know if @Martin Holladay will ever see this post and/or has any knowledge of such products. Or anyone with direct knowledge/experience with such products will chime in.

    I just don't know how the lower closed cell content affects the perm rating.

  5. mr_reference_Hugh | | #5

    I've written to these guys to ask if they can help.

  6. wt13 | | #6

    It looks like it's an "industry group?"

  7. mr_reference_Hugh | | #7

    I did write to but I have not heard back.

    DAP also offers a one component spray foam. Link here

    I called their technical support. They could only provide info that is available on the technical specification sheet. I had already looked and there was no mention of PERM rating. I asked the guy whether DAP tests their spray foam for PERM rating. He replied that if they do and it is not on the tech spec sheet, DAP does not release the information to the public.

    DAP is a pretty big company. I would rely on them more than smaller players on the market.

    My conclusion is that the fact we cannot get our hand on the PERM rating tells us what we want to know. It is not a reliable vapour retarder/barrier.

    Not sure if have a different opinion.

    I think I would spring for the 2 component spray foam. DAP has one large kit that is sealed in one canister that looks like a propane tank. It looks like a one component kit from the outside.

    Hope this was helpful.

  8. wt13 | | #8

    I have already started my cut/cobble project anyway, since I don't trust using such a product in that way at this point - especially due to the lack of even manufacturer/vendor information.

    For me, it was either this or cut/cobble - two-component is too cumbersome and expensive to me. I just wanted to put this information out because from Amazon reviews, etc., it seems like there are likely some users using these products in cold-climate areas and just relying on it being CALLED close-cell.

    I don't have the answer myself - because THEY don't have the answer, but it's use as an easy replacement for TRUE close cell (two component) in cold climates is suspect.

    I did notice, however, that the description has changed slightly on Vega's website:

    Vegabond Puplecoate Spray foam insulation for heat and sound for anywhere you need it. Provides a unique, continuous thermal insulation application without junctures, seams and gaps. An innovative alternative to traditional building insulation methods such as polystyrene heat insulation boards, glass wool and rock wool. Single-component product used with an applicator.

    Though note that XPS and EPS are both "polystyrene heat insulation boards" so it's a little vague from that perspective. But they don't say it's an alternative to two-component foam and the inference is there because of the reference to glass/rock wool that it's permeable.

    The bottom line, though, is I don't think anyone has actually tested the vapor/moisture permeance of using such a product standalone - or maybe I just haven't been able to find it. It's not like my Google-fu is finely honed.

  9. Expert Member
    BILL WICHERS | | #9

    I did actually go ahead and order some of this "big can" one part spray foam to try. I couldn't order the Vegabond stuff, so I got two cans of the "Kraken Bond Fastcoat " instead, which appears to be pretty much the same thing, just a different brand. Yesterday I finally got around to my small insulate/airseal project so I thought I'd update this thread.

    The nozzles that come with the cans won't fit on a regular canned foam gun. I taped the right nozzle on one of my guns (which worked OK, but wasn't perfect), but I will order one of Kraken's guns next time that has a little "fitting" on the end for the nozzles that are included with the can of foam. The can comes with two nozzles, one for "ceilings", the other for surfaces. I used the surface nozzle that is a vertical fan type of spray. I applied the foam in an attic a little above 50F (which is what I was waiting for -- a day of slightly warmer weather).

    My results were OK, and it was an irregular surface so not ideal anyway. The foam cures softer than two part spray foam, and feels more spongy, similar to Great Stuff. It expands rather slowly, so it looks really thin at first but puffs up over maybe 5-10 minutes. I didn't get a particular even layer of foam, but this was my first try with this stuff, so I'd put that down more to crummy technique on my part and not any fault with the product.

    I think this is a good product for small jobs, and by "small job" I mean large air sealing jobs, or very small areas of insulating. I would NOT try to use this stuff for a larger area where you're actually trying to use spray foam as the primary insulating material. I would use this in very small areas under maybe 10 square feet or so as primary insulation (think that last stud bay you missed on the big project), or large air sealing jobs where you have to cover some area and not just a small gap. In my case, I was at the peak of a catherdral ceiling area with an attic on one side and a vented catherdral ceiling on the other (and I'm taking the pics from the catwalk I built in the attic side). I was sealing the ends of batts under some vent chutes I installed since there were air leaks in this area due to poorly placed batts and possibly some holes in the drywall. There is a faux beam under the peak inside, so it's not really possible to fix any bad mudwork to seal the drywall from below.

    I found the product worked fairly well, and I made two passes to get what is shown. The first pass left some voids, which I tried to fill in with the second pass. The biggest issue was getting an even layer of foam down, which would probably be easier with more practice -- especially if you were working in a more accessible area than I was.


  10. wt13 | | #10

    Thanks for the info. I also tried asking Kraken, but at least the rep I spoke to didn't even appear to know what "perm" was, so being in zone 5 I decided to pass and went cut and cobble.

    From what I have read, all one-part foams have a max of about 75ish % to 25ish% closed cell to open cell (as opposed to two-part foams that run in the high 90s for closed cell content.

    I couldn't find any definitive answer on either what the perm rating of such foams are, or how the ratio affected vapor permeance since open cell is pretty high.

    Since I was looking in to using it instead of two-part foam instead cut/cobble in the joist cavities, I didn't want to take a chance of vapor being able to penetrate down to the rim joist and eventually rotting.

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