Foam removal
closetconservation
| Posted in General Questions on
Looks like I’m unfortunate enough to have been a victim of a bad attic install gone wrong. My roof was open-cell sprayed approximately 10 years ago.
Seems that part of the cathedral portion of the roof is deteriorating. As it turns out, the roof is about due for shingle replacement anyway (roof appx. 22 years old), but I am now in a situation where I cannot find anyone to remedy the situation. Plenty of companies willing to spray foam, no one has any idea how to remove.
Can’t get a roofing quote because local companies don’t know what to do.
Anyone have any advice? I’m in the Northeast USA (NY).
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Replies
You have to remove it mechanically. That typically means cutting out chunks, then sandblasting the remaining bits off of the wood (sounds odd, but it works). It's labor intensive and an all around nasty job to do. I would try calling some remediation companies that work with asbestos and mold, ask them -- those companies are usually used to selectively removing problematic materials from a structure.
Bill
Deteriorating, the foam the plywood the structure?
Looks like the plywood.
This pic from last it snowed couple months ago..
Some slight sagging.
Thanks Bill,
I'll see if I can try to contact a company like that. I was thinking though, if the sheathing is already compromised (as it's looking like it), and if the roofing company would be removing parts of sheating and replacing it with fresh plywood anyway. Would the remediation company still have to do all that work? I mean, I guess they would know better than I would, but I would think it would be easier to work from the outside in if the roof ends up having to be replaced.
Some remediation companies will do all of that, including the roof. Look for those "insurance repair" contractors, they often do multiple kinds of work like this.
BTW, Akos mentioned open cell being relatively soft, and he's right. You can use drywall knives to scrape that stuff off of framing. Just use a very wide knife. If the foam is chemically OK (i.e. it cured properly), then you don't really have a hazardous situation here, so you don't need to fully remove the old stuff (i.e. no need for sandblasting).
Bill
If the issue is only the roof deteriorating, you don't necessarily need to remove the foam.
The reason the roof deck is failing is moisture buildup, so you need to add a way to vent it. Replace the damged section, strap over the roof with 2x4s on flat to create a vent channel and install a new roof deck followed by new shingles.
Another way to vent moisture is instead of shingles is go for one of the tile roofs (slate, concrete, metal) and use a permeable underlayment under it.
If the rot is only near the ridge, you might be able to get away by adding a diffusion vent only:
https://buildingscience.com/documents/insights/bsi-088-venting-vapor
In either case you create a path for moisture to escape so the open cell foam bellow is fine.
Open cell is pretty soft, so if a large part of the roof deck needs to come out, there will be a lot of damage. In that case, mechanically removing the foam (low density stuff you can scoop it out by hand) is probably the easier. If you are not dealing with chemical issues with your foam, it doesn't need to be fully removed. You can re-insulate with batts and do either of the above venting options.
Just so I have a better understanding..... If a roofer starts removing shingles, then sees that sections of decking needs to come out, I'd be left with some interior parts of foam broken up, and other sections intact.
I should be anticipating using one of the methods to vent and and think about replacing broken sections with batts or something?
I read the linked article. Do you think it would be prudent to do both the "double-layer" of sheathing, PLUS the ridge vent?
I'm just thinking this plan through because so far, one roofer bailed after he came, another spray foam company bailed and an molde/asbestos remediation company claimed they don't do that kind of work. So, I'm thinking it'll take time to find someone. In the meantime, I don't want to go to long with this issue so I'm thinking do the double-sheathing method, then hopefully it'll buy some time till I can get the interior attic addressed.
I climbed into the attic to take a closer look and it looks like the original foam company sprayed all around the sky lights but didn't completely remove the pink insulation that was stuffed in that corner. I'm guessing in many spots that there are gaps where the foam is not directly in contact with the sheathing. Very tight in there and would be difficult to squeeze a body in their to remove foam if necessary.
"I should be anticipating using one of the methods to vent and and think about replacing broken sections with batts or something?"
Yes, you can fill any gaps with fluffy or canned spray foam.
"Do you think it would be prudent to do both the "double-layer" of sheathing, PLUS the ridge vent?"
Double layer with venting is the proper fix. Important part here is the underlayment over the original roof deck needs to be permeable (ie Gaf Deckarmor).
The diffusion vent is a band aid that doesn't need the double deck and can work if you have only problems near the ridge. Looking at the sagging roof, that is not likely the case for you.
"I'm thinking do the double-sheathing method, then hopefully it'll buy some time till I can get the interior attic addressed."
If you fix the roof above, there is no need to fix anything in the attic. Unvented attics with open cell spray foam needs to be conditioned though so if you don't have a dehumidifier or supply vent from your HVAC up there, that needs to be added in.
I'm a little confused about something...
When I look at some of the info at building science, their pictures don't show the "air channel" over the top layer of sheathing. I only see the insulation in between the lower & upper decks.
The info suggests that the venting is mostly for climates where it snows a LOT. I'm in climate zone 5, so I'm not sure if that means a LOT.
Also, a roofer I spoke with is also recommending gable vents in addition. But my understanding is that would be worse.
What does the foam look like on the back side that touches the OSB? I am going through the same thing but mine is a brand new construction home that was completed less than 2 years ago. The removal of foam can be accomplish from the attic side with your hands, putty knife, scrappers, crow bars etc but if the foam that touches the OSB is growing mold then you will have to replace all the osb on the roof. I have quotes from several companies that are willing to do the work from the attic side and I have one quote from a company that will replace shingles, osb, foam in sections then replace the entire assembly in sections pending weather. I have approximately 9000 sq foot of attic roof decking. I can tell you how I am going to do it, but in your instance it depends on "who is paying"?
"I have approximately 9000 sq foot of attic roof decking. I can tell you how I am going to do it, but in your instance it depends on "who is paying"?"
Me unfortunately. Appx 2700 sq ft. colonial style home with attached garage. I'm sure any quote is going to wipe me out & send me into shock.
From a glance, the foam looks ok, but I don't like that I can still smell it (slight "fishy" smell). And most unfortunately, the space over the garage has been finished so no way now to get to it from inside except to basically re-do the inside construction.
I think I'll climb around best I can again with a strong flashlight.
Where in NY are you located?
Orange county (mid-hudson valley) NY.
Something occurred to me. Over the winter, I had a ductless mini-split fail at the coil (developed small leaks). HVAC manufacturer insisted that it was unusual if installed correctly and at first didn't want to warranty it. Saying it may be caused by using aerosol sprays and such. Which I don't use.
Does anyone imagine that something like that could be caused by off-gassing?
There was a spate of issues with Fujitsu air handlers pin holing. There was apparently also an issue with some open cell spray foam installs corroding the coils, not sure what the mechanism was. The two are not related, so depending on what your issue is, the manufacturer could be right.