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Did my contractor install open cell when he said he’d do closed cell?

1910duplex | Posted in Energy Efficiency and Durability on

So we finally pulled the trigger and hired a company to do two inches of closed cell foam at attic decking and one inch along eaves. It smells slightly like mildew 24 hours later. It seems softer than I was expecting, especially where it looks ‘bubbly’ … I asked for Lapolla Foam-Lok 2000-4g. Pictures below. I can even poke a finger in. (Last picture shows that) Did I actually get closed cell foam?? Also, what should I do about the several spots where the foam is pulling away from the rafters? Not counting the bubbly edges, it seems I have 3 inches left in the 2 by 6 rafter bays. Will the R-23 mineral wool batts still work compressed in that space? If not, should I get R-15 instead? (Is that enough to be safe as thermal protection in a space used for storage)? We will be putting half-inch drywall on the vertical walls/eaves, where the foam nearly fills all the space) Should I cut away the bubbly edges? Should I do any caulking between chimney and rockwool? They had said they would but then didn’t bring any.

Thanks for all your help.

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  1. Expert Member
    BILL WICHERS | | #1

    Closed cell spray foam is usually pretty hard, but it does vary a little bit by the density of the particular product you had installed. My normal test is to try to snap off a piece -- close cell should break with a SNAP and leave a clean, fractured edge. If it tears and leaves a ragged edge then I'd suspect open cell was installed.

    If you only have 3" of space left and you want to fill it with mineral wool, use the "sound" product (goes by various names from different manufacturers, but is sold for sound suppression and fire blocking instead of insulation) intended for 2x4 cavities. The "sound" product for 2x4 cavities is 3" deep and would be a perfect fit in the space you have, no compressing needed.

    You'll want to trim the foam flush to the rafter edges prior to installing drywall.

    Give it a few days WITH AIR CIRCULATION to let the smell go away. I usually recommend applying the spray foam on a Friday, then leaving town over the weekend. Normally when you return after 2-3 days the smell will be mostly gone.


  2. 1910duplex | | #2

    yeah, it does not break with a snap. And I can poke a finger in, which seems like a sign it's open cell.

    Since I did not want open cell, and I am concerned about moisture in the plywood from radiating heat cycles, do I need install a smart vapor barrier like MemBrain over the rockwool?

    1. Expert Member
      Dana Dorsett | | #3

      >" I need install a smart vapor barrier like MemBrain over the rockwool?"

      Even if they had installed closed cell foam, a smart vapor retarder would still be a good idea.

  3. 1910duplex | | #4

    Dana, do you agree this doesn't look/sound like closed cell?
    Do you agree I now need to go with the thinner rockwool (I had bought the R23 on your recommendation, it's on order).
    Or would it be best to get the rest of the rafters filled with open cell if they will do it since they gave me the wrong product?
    What should I do to remedy the places where the foam is pulling away from the rafters?

  4. MattJF | | #5

    Where are you located? If it is cold out, it is likely that the surface being sprayed was too cold, which can result in poor adhesion and potentially poor foam formation. Most of the foams require a substrate temp above 50F or so.

    How much of the foam is pulled away like that. A couple spot would not be unheard of, but I high percent would be a problem.

    Was the installer approved/trained by Lapolla?

  5. 1910duplex | | #6

    I am in 4A, the work was done Tuesday in late morning; it was in the 50s at that time. The company says they are certified by RESNET (Residential Energy Services Network)... had lots of good reviews on Angies List/Consumer Checkbook.
    I haven't looked carefully in every spot of the attic, but I have only seen three places so far. My question is do I need to put caulking in that gap to airseal?
    I have emailed Lapolla with the pictures below to ask if this looks like 2000 4G to them. (Especially the picture where you can see I can dent the foam with a finger)

    1. Expert Member
      Dana Dorsett | | #10

      The shrinkage cracks & separation from the framing in those pictures is a show-stopper. It was either the wrong mix, wrong temp (of either the foam or the substrate or both), the wood had too high a moisture content, or all of the above. Those pictures rate among the crappiest installations of closed cell foam I've seen in recent years.

      Let's see what Lapolla has to say before calling the lawyers.

  6. Expert Member
    Akos | | #7

    You can cut out a cube of the foam and weight it on a baking scale. For 2LB closed cell SPF, a 6"x6"x3" block should be around 0.12lb (2OZ). Open cell would be around 1/2 to 1/3 of that.

    To me it just looks like a bad install on too cold sheathing or the mix was off. Maybe there was even some dew on the rafters when it was sprayed, thus the adhesion problem.

    All the closed cell I've have worked with were pretty solid. You would have to punch it pretty hard to create a dent.

    I would try to seal up the gaps with canned foam. A drinking straw usually fits over the one on the cans and it can get into pretty tight spaces.

  7. walta100 | | #8

    Did the contractor give you a written contract with the words “closed cell”?

    It seems unlikely the manufacture will offer an opinion from photos. I think you would have better luck asking for a sample of their open and closed cell products and you can draw your own conclusions.


  8. 1910duplex | | #9

    Yes, we signed a contract with the words closed cell. I really want to get to the bottom of this so I can figure out what to do now since it's not really possible to remove the foam that has been applied. We have only paid half of the price so far.

  9. MattJF | | #11

    Do you have some photos of the larger area? In the eaves and tight areas where it is difficult to get normal to the wall when spraying, the foam is more challenging to put down correctly.

    Do the larger open areas look the same?

    I would contact lapolla and ask them to analyze a sample. I would also have the installer come back to review. Is the company owner the one who sprayed or did he send a separate crew?

    Don't do anything yet, you are going to want to have access to this foam for any corrective actions or tests that are needed. Continue with ventilation, fans in the windows for a few days.

  10. 1910duplex | | #12

    It is a pretty big company. I have met the estimator/sales person; this was a separate crew.
    The pictures where you see the separation from the rafter or the crack in the foam are not in the eaves. They are on the main part of the roof, in a very easily accessible area (full standing height).
    Can link more pictures later.

    Mostly the foam is flush against rafters, but tends to have big bubbles more often at the edges of rafters, and looks denser/tighter in the middle of the bay (the rafter bays are generally about 20-22 inches wide). But even where I have pressed in the middle of the bay, it is pretty yielding (and that's where the finger dent is from)

    I have contacted the salesman/estimator asking him if this really was 2000 4G, given the easily dentable/tearable quality, and offered to schedule a visit for him to come look.

    We have had the windows open for about 12 hours, but will start running a fan.

    The rockwool is on order and won't be coming in for weeks, so no worries there... and if I have to change it to R15 rather than R23, as @Zephyr suggested, that will delay shipment further.

    1. Expert Member
      BILL WICHERS | | #13

      The “sound” stuff I mentioned is NOT the regular R15 stuff. The “sound” stuff is the same material, but a little thinner, so about R12.8. The advantage for you is it’s already cut to 3” deep, so it will be a good fit in your 3” space. Normal R15 mineral wool is 3.5” deep.

      A better option would be to have the spray foam contractor fill the rest of the bays with open cell foam. If they’ll do that to “make it right” after installing the wrong foam by mistake, I’d do that. Have them trim the spray foam flush with the bottom of the rafters (which would be standard practice if this was a wall or a ceiling in a finished space), and install MemBrain over it as Dana suggests before you put your drywall up.

      BTW, a pneumatic staple gun for regular staple gun stapes (not the usual construction staples) is a HUGE labor saver for putting up vapor retarders like MemBrain.


  11. walta100 | | #14

    I asked the question about the contract because if they had a planed to sell closed and spray open the contract would have been vague. If the contract is clear the contractor is more likely to be honest and make things right.

    I am not sure it is a valid test but logically if you submerged a sample of closed cell foam in water for a few hours it should float and open cell should not.

    You may find this document interesting.


  12. 1910duplex | | #15

    Hi all, you are the best! I have a good news update -- after another eight hours of curing, it is definitely appearing more like closed cell foam. The denser areas are very hard in most of the attic, and even in the eave where it is squishier, it's not so soft that a finger sinks in and leaves a mark. The bubbly areas are more yielding, but do 'snap' when you break a bit off. The bit I left in water did float. So definitely was closed cell.

    They shaved the foam along eave walls so drywall can be installed there; it feels like styrofoam there, pretty yielding. (second to last and third to last pictures)

    The smell was stronger when I returned after eight hours, even though windows were open all day, but now seems to have dissipated. (I opened a window on the other side of attic and put fans in both sets of windows; leaving windows open today JIC).

    The company is going to send a superintendent out to check out the install. I know to ask to remediate the places where it is not adhering to rafters and the places where it cracked, but do I need them to do anything about a 'belly button' type effect (photo number 10 in new set below).

    For those who wanted to see more pictures, including more big picture ones, a new link is below. The bare wood you see is the party wall to the other half the duplex; she insulated at roof decking, though just with fiberglass batts.

    After all this is done, we will be putting up R-15 rock-wool batts in rafters and drywall on the eave walls where there is no more space for insulation. Do not plan to hang drywall everywhere.

  13. Expert Member
    BILL WICHERS | | #16

    The lumpy “belly button” effect is pretty typical for spray foam. You won’t normally have a flat/smooth surface on untrimmed foam. This is nothing to worry about.


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