Closed-Cell Spray Foam Failure
thirtywest
| Posted in General Questions on
Well, my spray foam failed. thanks for stopping by…
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What kind of substrate and how high a lift?
5/8 zip. accuvent. 8" 24'oc roof
Former spray foam contractor here, I think what was meant by “lift” is that in the proper application of closed cell foam, you make a pass between joists or studs that allows the foam to rise (lift) to only a few inches
If more is needed, you make another pass after it has fully cured
That really stinks. It made me think of something shared in Scott Gibson's Spray Foam Gone Wrong post: Spray foam that is applied in too thick a layer may crack as it cools and contracts. This defect can be repaired by slitting the foam to relieve internal stress and applying new foam on top. Definitely read that post, if you haven't, to see what your options might be.
Thanks all. I more just posted incase anyone was keeping score. I suspect that it was put on too thick. The sprayer did that section very quickly. Strange thing is it took 2 years to break like that. It must have had an immense amount of tension to break like that. The company is coming by tomorrow to take a look at it. Anyone have thoughts on whether it should be filled or the entire bay emptied? Here's one from the outside...
To be honest, I'd be hesitant to have them remove it and re do it. You said it's been a few years already? Does it have any smell or other indicate of a failed application? Personally I've read enough horror stories on this website that if you have no issues with it other than the crack, and thermal imaging does not show any major voids or other issues, I would just be scared that if they remove it all and re do it, the re-application might have bigger problems than the crack... like fishy smells that never go away...
While spray foam 'chemical failures' are horrific, considering how much spray foam is installed, I think they are pretty rare.
I think I would inspect the entire attic to see if there are any places that look somehow suspect, show them to the contractor and have them repair.
IT seems to me one would at least want to cut back the foam so you get good penetration with the new foam, and obviously make sure they are layering it properly.
This makes the most sense to me. I would certainly not just leave it and filling it with something like can foam seems prone to failure. I will be curious to see what the contractor suggest in terms on how much material removal to do. I also think that chemical mix failure is much more common in open cell, but perhaps that is more a factor of being able to perceive it.
Sorry, I lost track of this thread... The contractor has offered to tear out the entire job. The foam has cracked in two other spots. I haven't decided what to do as of yet. The insulation manufacturer has done a core test and said that everything is fine with the product. Typically they do not like to use Accuvent, as they prefer an unvented system that would adhere to the roof sheathing. The speculation is that the plastic accuvent is shrinking in the cold nights and splitting the foam. Any thoughts?
We always used foil-faced foamboard to create a vent space...
It pretty easy - you cut the foamboard a few inches bigger than the joist. You score one side & flip it over to create the vent space, tack it in place & spray onto it!
That probably would have been better....
If it's cracked in multiple places like you've said, I'm not sure what else to say about thoughts.
If you no longer vent, that's going to be an after the fact rip out of the current.
Since you are at only 8", you have 7" of something else. Can't be done in the bays without spray foam.
How in the world will tear out work since the product glues fairly well? Even my incidental particle splatter doesn't just flick off. You're not going to end up with perfectly clean bays is what I'm say.
Your house looks newer? The green community needs to advocate for no more framing that can't accommodate non special insulation (foam or Cathedral high density that isn't always available). If someone wants to do spray or exterior insulation? great. But make a building that can accommodate actual R values without this stuff.
If it's cracked now, rip it out. You can't expect it to stop cracking as time goes on.
The installer said the removal will be easy because of the accuvent. apparently it just comes out in huge sections. yes, depth is a problem with most attic applications. Its hard for a single home owner to advocate for themselves let alone an industry.
100% agree.
If we the non pros keep pointing out the failures, which even when looking can be difficult for the non experts to tease out...maybe it will push the actual pros to put some articles and action behind it.
From the long term, think of the future we've built with this garbage. Eventually roof sheathing will have to be replaced--because no one is building or maintaining their roof perfect. Then what happens to all the interior install cathedral ceiling spray foam? The experts created a standard for multiple options, but the reality is they created a one solution problem with spray foam. In the end, if my builder had been required to build with 2x12s for insulation fit alone, I would have been far better off. My 2x8 even fired on flat down with 2x4 still can't fit anything but foam. That's a ridiculous situation placed on the home owner.
Good luck. I'd read your follow up when you posted.
I'm not sure what to do as of yet. I was even thinking rock wool with interior foam. I'll do an update when the time comes.
Ryan_SLC,
The drawings you submitted for approval should have included an outline specification for each assembly, showing both how they were to be built structurally, and insulated to meet the required R-values. The failure to do that is on whoever designed your addition, not your builder or some un-named "experts". The role of building codes and inspectors is to set and enforce agreed upon standards, not to design, coordinate, or build your project.
I am not trying to place blame or claim any expertise. I only posted this out of interest in buildings in general. I retouched on it to see if there were any thoughts on the accuvent being the culprit. seems like if its a potential failure that people would like to know.
thirstywest,
No aspersions intended to your posts. I was replying to Ryan's complaint that no one protected him against using too shallow rafters, which limited his insulation options.
face same issues ....