What should be done with scrap foam?“Open-cell spray foam is mostly comprised of air and is completely safe to take to a landfill,” said Clark, whose post includes a link to Spray Foam Energy Solutions, a California company. “It will crush down to almost nothing when driven over with tractors commonly used to compact the waste stored there. Contrary to common belief, there is very little decomposition going on in the landfill except for food waste as a few minutes with Google will attest.”And that’s the problem, said Riversong.“Plastics last virtually forever in landfills and elsewhere in the environment, including the great Atlantic and Pacific garbage patches, where they do break down in size, becoming smaller and more dangerous to the biosphere,” Riversong added. “Green materials compost back into their natural constituents and become food for new life.“And you’re completely wrong about pieces of cured foam acting as an air barrier,” he continued. “It is an air barrier only when foamed in place or placed as a tightly-fitted and sealed rigid board.”The potential for environmental and human damage from petrochemicals and chemical additives is troubling to some posters.GBA advisor Michael Chandler, for instance, wrote, “The fire retardants in spray foam and board foam are a bio-accumulative neuro-toxin, so disposing of waste foam in a landfill is not doing the planet any favors.”Like John Brooks, who wrote that he is moving away from foam, Chandler is looking for alternatives to spray foam and rigid polystyrene board in the houses he builds. “I’m not there yet,” he said, “but moving in that direction.”Chandler attributes his change in thinking to some conversations he and his wife had with Arlene Bloom at the Build Well conference last year. “She and Theo Colburn really got me thinking about the unintended consequences of some of the chemicals we use in our pursuit of improved energy efficiency,” Chandler said.Riversong added, “Of course we would not find ourselves so often surprised by the unintended consequences of our choices if we used the Precautionary Principle, which requires that any new thing be proven safe (and necessary) before introduction into the marketplace and environment, rather than waiting until someone discovers it to be unsafe. On that basis, it would be reasonable to assume that all 80,000 petrochemicals we’ve created, that never before existed on earth, are unsafe until proven otherwise.” First, will it work?GBA senior editor Martin Holladay doubts much will be gained by Halkias’ plan. First, exposed foam is a fire hazard, Holladay said, and used in this way it won’t offer much in the way of insulation: “Unlike undisturbed foam that is sprayed in place, broken pieces of cured foam provide no resistance to air flow,” he wrote. “I doubt whether they provide much R-value, since air can easily pass through the broken pieces of foam.” UPDATED 1/19/11 with comments from Peter YostOpen-cell polyurethane foam expands dramatically as soon as it hits its target, rapidly filling wall cavities and typically mushrooming beyond the stud line. After it’s firmed up, installers trim away the excess so drywall or other wall finishes can be put up.The installer who sprayed open-cell foam into the exterior walls of Peter Halkias’ house has packed up his truck and hit the road, leaving him with “bags and bags” of excess foam. Halkias knew up front that disposal would be his problem. Now he wonders what to do with it, and whether it can be broken up into finer chunks and spread over the fiberglass batt insulation already in his attic.“Are there any code violations involved in doing this?” he asks in a Q&A post. “The only thing I can think of is an issue of flammability. The attic is fully vented and any light fixtures located in the ceiling joist bays are rated IC and airtight. I am trying to kill two birds with one stone: Get rid of the waste and add some insulation R-value to my attic ceiling.”The replies to Halkias’ post, the subject of this week’s Q&A Spotlight, touch not only on the merits of his plan but also the knotty disposal issue in general. And like a concurrent thread elsewhere on the site, it’s an opening to discuss the potential downsides to spray-foam insulation. RELATED ARTICLES GREEN PRODUCT GUIDE Sprayed InsulationHowever, Bill Clark disputed Holladay’s advice. According to Clark, many spray foams are approved for use in attics without any fire coating. As to the insulation value of the offcuts, Clark said, “Excess cut-off spray foam insulation will generally NOT allow air to pass through it, and even if it does, all traditionally used insulation products except spray foam allow air to move through them.”John Klingel wondered whether the pieces of excess foam could be pitched into the hopper with cellulose and blown in over the fiberglass batts. “I would guess that the foam being shredded and mixed with the cellulose would at least postpone its getting to the landfill,” Klingel wrote, “and in the meantime it could be doing some good. No?”Actually, no, said Katie, who identifies herself as a spray foam contractor. Katie backed up Holladay’s analysis. “We wouldn’t recommend shredding up open-cell waste and putting it in your attic (or anywhere, really), for all the reasons discussed: fire hazard, no air barrier, no insulation value,” Katie wrote. “Plus, dust particulate would be an issue. We once tried putting open-cell waste in our fiberglass blowing hopper to shred it up and blow it in an open space just to see what would happen and if it could be done. The hopper reduced the insulation to fine pellets and there was a ton of dust. Hardly worth the time or effort to ‘recycle’ the foam when the only thing you’ll gain is a fire waiting to happen.” Whose responsibility is it?Halkias wrote the contractor stipulated in his contract that he would bag the waste and clean up the site, but would not be responsible for disposal. “This being my first spray foam experience, I did not realize the waste that would be generated,” he said.Whether the contractor was upfront about it or not, leaving waste materials behind for the homeowner to deal with seems an odd exception in the building trades. Offcuts from framing lumber, drywall scraps, plumbing and wiring odds and ends and all the other debris from construction is usually taken away by the sub, or at least pitched into an on-site Dumpster by the general contractor.“I think that any spray foam contractor who doesn’t take responsibility for job waste is irresponsible,” wrote Holladay. “One way of shaming this contractor is to name the company and the city. Any company that claims to be environmentally responsible should have a waste disposal plan,” he added. “If a contractor’s routine work generates waste, then disposing of that waste in a responsible manner should be part of the contractor’s routine services — in my opinion.”“Every construction or remodeling contract should end: ‘The site will be left broom clean,’ ” said Robert Riversong.But maybe the practice is common in some areas. John Brooks said the practice of charging to haul away foam waste is common in North Texas, according to the contractors he’s spoken with. “The amount of waste with an open-cell job can be LARGE,” he said. “Not only is there a FEE … there is a high volume of foam filling up the landfill.” Spray Foam Insulation: Open and Closed Cell Does Spray Foam Insulation Out-Gas Poisonous Fumes? Open-Cell Foam Beats Closed-Cell FoamRigid Foam Insulation Industry “still in its infancy”Some spray foam installers may be pushing spray-foam as the greenest thing since LEED, but you won’t find Katie among them.“As a spray foam contractor, we are not in the habit of buying into the ‘Foam is Green’ marketing ploy and do not sell it as such,” she wrote. “We install open- and closed-cell spray foam for its high insulation value and air barrier qualities (when applicable) to people who can afford the upgrade. Period. We are honest with people who are considering foam: it’s expensive, it’s combustible, it’s plastic, and the initial off-gassing (although more dangerous to installers than building owners) during install may be a nuisance to sensitive people.”Still, she added, spray foam has some tremendous advantages.“The spray foam industry is still in its infancy, and there’s a long way to go until it becomes a respected and viable industry, like cellulose and fiberglass have,” Katie added. “Yes, there’s a lot of waste with open-cell, no matter how good an installer you are. (Waste is different than overspray, by the way.) Yes, the product can’t be reused and takes up a lot of space in landfills. But what insulation is truly green? None that we can think of.”Our expert’s opinionHere’s what GBA technical director Peter Yost had to say:Insulation value in attic: I agree with Martin and Katie; there is no net gain to be accomplished with this effort.Responsibility: Dealing with the overspray and cut-off waste definitely is the responsibility of the installation contractor and, as Riversong stated, easily covered by the standard “broom clean” contract language. And a really good reason for this is that if the contractor has to deal with the waste, what better way to ensure that the contractor has incentive to minimize this waste?Cutting versus “roller-shaving:” Big difference between these two in terms of dust creation when removing the overspray. The dust from roller-shaving the excess can be substantial and pervasive, making for a nuisance to most of us, and a health issue for sensitive individuals. When we used open-spray foam to insulate exterior walls in our own basement, the excess was roller-shaved. While the contractor left the basement broom clean, an acrid dust covered just about everything and proved to be a real problem for our daughter with asthma. After a full day of HEPA-vacuuming every exposed surface we were fine, but cutting at least most of the excess would have created a lot less dust.Spray foam insulation contractor certification: In Canada, this is required. The U.S. needs mandatory spray foam insulation contractor certification to separate the wheat from the chaff.Flame retardants: While open-cell spray foams have a good profile in terms of global warming potential they typically contain brominated flame retardants as Chandler pointed out. Selecting the most benign and highest performing insulation remains a real challenge.