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Highlights from Joe Lstiburek’s 2012 Experts’ Session on Spray Foam

Building Science Experts Session Joe Lstiburek Spray Foam Insulation

Spray foam insulation evokes some interesting conversation among building science professionals, those in construction, environmentalists, and homeowners who have it in their homes. Many think it solves all problems, no matter how poorly it’s installed. Some think it’s helping to warm the planet and compromise the health of people and pets. In the middle are those who work with it regularly and see both the warts and the beauty of the product.

Spray foam insulation evokes some interesting conversation among building science professionals, those in construction, environmentalists, and homeowners who have it in their homes. Many think it solves all problems, no matter how poorly it’s installed. Some think it’s helping to warm the planet and compromise the health of people and pets. In the middle are those who work with it regularly and see both the warts and the beauty of the product.

Building Science Corporation is hosting its annual Experts’ Session, and the first day was all about spray foam insulation, with a collection of people who are mostly in the third camp mentioned above. Joe Lstiburek spoke first and then brought in several experts to give us high level information on this product – everything from the basics of open cell versus closed cell to the latest work on blowing agents.

The other invited speakers were:

A quick overview

Joe began by talking about the Perfect Wall. That led quickly to what he calls the 500-year wall, for 3 reasons: It represents 500 years of evolution; it lasts 500 years; and it takes clients 500 years to pay for it. He went through some of the details he presented in his Perfect Wall paper on the Building Science Corp. website, discussing where to use foam, which foam works, and how not to do stupid stuff.

Of course, he also took his jabs. He called out ASTM at Summer Camp this year. Yesterday, he said that ASTM stands for Another Stupid Test Method. He also continued the anti-WUFI campaign I first heard at the Passive House conference in Denver. In discussing how you decide what vapor permeability you want in your materials, he said, “You guess. I’ll trust your guess better than a WUFI analysis. WUFI should only be done with adult supervision.” (WUFI is a modeling tool for moisture and heat transport through building assemblies.)

Mac Sheldon of Demilec gave a great talk titled SPF Retrofit Problems & Solutions. He discussed how controls have improved to the point where spray foam going off-ratio, while still possible, is becoming rare. He did show some of the problems that occur, including a scary photo of a box truck with the roof blown off because someone put water in the wrong drum. That drum ended up across the street.

Installer errors are the most frequent problems, and there’s been a concerted effort in the industry to improve in that area. Sheldon discussed the new accreditations and certifications that SPFA offers, and Rick Duncan went into a bit more detail about them. If you’re in the business of installing spray foam, get over to the SPFA website now and start getting your workers certified.

One of the big issues in the past couple of years has been the blowing agents used in spray polyurethane foam, specifically HFC-245fa used in closed-cell SPF. This whole thing blew up when Alex Wilson of Environmental Building News wrote a paper in 2010 in which he concluded that closed-cell SPF and extruded polystyrene (XPS) had too much global warming potential (GWP). He made his paper look like science when it wasn’t and made so many assumptions that his results were not valid. I wrote a response to his paper in August 2010, Don’t Forget the Science in Building Science, but more people read his paper than mine, and sadly, too many people believed his.

Yes, Alex did have a point about the blowing agents, and he should have just said that he didn’t like them instead of trying to calculate bogus ‘paybacks.’ The good news for those who care about the GWP of materials is that the speakers from Honeywell announced their replacement for HFC-245fa, which they call Solstice Liquid Blowing Agent. It has a GWP of less than 5 (HFC-245fa is greater than 1000) and will be available starting in 2013.

The last speaker of the day was Paul Duffy of Icynene. He discussed some of the basics again and, as several other speakers had done, he hit the issue of safety pretty hard. “It’s going to be an obligatory part of SPF presentations from now on,” he said.

Duffy also gave the most jarring example of the day. To illustrate how much pressure the liquid is under when it comes out of the gun in a high-pressure SPF rig, he asked, “What do you think will happen if I aim a foam gun at my hand? It will inject foam under my skin and expand when it gets there.” And remember, low-density, open-cell spray foam expands to 100 times its original volume very quickly. Imagine the Michelin Man on steroids.

My take

It was a great day packed with good information. In addition to what I mentioned above, the speakers also hit on the topics of ignition barriers, fires, lawsuits, and odors…briefly. I like spray foam, but I’m also wary of some of the drawbacks. As with most of our technology, though, it works well when used appropriately and poorly when it’s not. It’s still true that the process is more important than the product. We need to get a lot more people in building science and construction to really understand what that means, and Joe’s day-long symposium on spray foam was a great way to help with that.

And a tiny foreshadowing…

I got to meet the inventor of the Turbo-Thermo-Encabulator Max! I’ll be interviewing him today or tomorrow and will post a video of it as soon as I can.


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This Post Has 11 Comments

  1. Day 2 

    Day 2 
    head over to GBA and you can watch day 2 live 
    hurry up starts at 8:30 Eastern

  2. Thanks for being our insider.
    Thanks for being our insider. Do you have any notes from Joe’s portion where he talking about rim joists in which he describes using a large piece of backer rod? I was coming in at the end of that and did not catch the details. I think it was what to do if there was exterior foam and spraying the interior of the rim joist–to allow drying in at least one direction and avoiding the “foam sandwhich”. 
    Any notes that you would like to share from the barn?

  3. Don’t forget the science,
    Don’t forget the science, sure, but don’t forget the common sense either! Alex Wilson was fundamentally RIGHT, even if his “payback” charts were contrivances. 
    At ANY release-rate, if the initial amount of blowing agent has the GHG potential of decades of the energy use offset (at some presumed energy source), it doesn’t really matter if the daily or annual rate is net-favorable. 
    Since there ARE existing alternatives to XPS and spray polyurethane products high potential blowing agents for XPS and spray polyurethane. Even if it takes 2 centuries for the nasty stuff to get out, it IS going to get out, and it’s far more malign than using materials with very low GHG potential. 
    It’s good that lower impact blowing agents are soon to hit the market, but until it does I’m still advising the use of EPS & iso over XPS, and water blown 2lb foam like Icynene MD-R-200 over their HFC245fa blown MD-C-200, or Aloha Energy’s 1.8lb water-blown closed cell foam.  
    At any release rate the net impact of the low-impact blowing agents is still going to be dramatically lower than those 100x or more powerful. Net total is still net-total, whether it’s all released to the atmosphere in the first 200 minutes, or the first 200 years. Global warming is a centuries long issue, after all, and it’s the net total over the decades & centuries of both the materials and the energy use that counts, far more than some modest daily-rate comparison of simply not-insulating. Using lower impact goods to achieve the same energy reduction is always a net-win, and the century-long difference is significant. 
    And it doesn’t take careful measurements with well-vetted mathematical models on release rates to reach this conclusion. 

  4. Thanks for sharing Allison!
    Thanks for sharing Allison!  
    I don’t think I’ve ever seen anything but 5 star posts from Jamie Kaye. “I still find that if I do a blower door test and infrared scan of the home after spray foam, we find another 10-50% of air leakage that was missed. ”  
    I don’t know how foam guys don’t have blower doors as part of required rig equipment. I find this to be true for the cellulose guys too.  
    Just because the work “looks perfect” doesn’t mean it is. Such a shame to find a bunch of easily corrected issues after the rig is long gone.

  5. Ted wrote: 

    Ted wrote: 
    “I don’t know how foam guys don’t have blower doors as part of required rig equipment. I find this to be true for the cellulose guys too.” 
    You’re singin’ my song. It’s real simple. Any contractor who touts foam (or any product) as a means to a tight envelope needs to put money-where-mouth-is by including a blower door guarantee in their contract. End of story.

  6. Allison, 

    Do you know if there is any way to get a video copy of this presentation? It sounds like it was very constructive and would be a good teaching point for the industry and many of us who are involved in the manufacturing of and selling so spray foam.  

  7. As much as we should debate
    As much as we should debate about the pros,cons, and horrors of spray foam, we do need to keep in mind what it replaced … the “swiss cheese” wall assembly. I’d say that closed cell foam has made the most significant contribution to eliminating the jetstream as a method of building ventilation. When you weight the GWP of foam to the GWP of “buildings that breath”, foam suddenly looks pretty darn good. Maybe the real topic of conversation needs to be where to best use closed cell foam rather than if it’s a good idea in the first place.

  8. Jamie K.:
    Jamie K.: Good points. On the SPFA certification page, you’ll see they also have one for spray foam inspectors.  
    John Z.: Sorry, I didn’t write anything down about those details and don’t recall enough to try to reconstruct it two days later. Notes from the barn? We just hung out and talked. 
    Dana D.: I agree. Alex had a valid point in criticizing the blowing agents, and I would have been fine with his article if he’d made it clear that his paybacks were contrivances, as you say. The thing about new blowing agents is that it’ll take a while before we know all the ‘side effects.’ Chemistry is a complex business. Plus, BSC is doing some very interesting research on R-value. Chris Schumacher has talked about it at Summer Camp the last couple of years, and I think the results are going to rock some people’s worlds. 
    ted k.: Yep. Insulation rigs should never be far from Blower Doors. 
    David B.: Yep. It’s like HVAC contractors and duct testers. 
    William C.: Yes, Green Building Advisor is going to make part of the sessions available to their GBA Pro members. See the bottom of my Day 2 post for a link to their site. 
    Tom B.: Agreed!

  9. Call me somewhat ignorant
    Call me somewhat ignorant about the topic of spray foam. I’m comfortable with that … it puts me in the majority. 
    I used spray foam extensively in my own home – a home that I designed and built just 3 1/2 years ago.  
    Blower door testing proved it’s energy efficiency when construction was completed. I have the framed certificate to prove that it – my own home – ranked among the most energy efficient homes in the central midwest. “Tightest home I’ve ever tested” was the comment made by my blower door guy.  
    More recently I’ve also had the opportunity to do some testing and forensic evaluation of of similarly “young” spray foamed structures.  
    When you’re doing forensic evaluation of a fairly young building, something has gone wrong. In these cases, wall sections which had been tight initially, were now leaking air causing water to condense and accumulate in portions of the assembly that are most vulnerable to decay.  
    Is that a failure of the foam or the piecemeal manner in which various air barrier components were joined together? The answer to both questions is Yes.  
    Our industry is slowly getting better at designing durable connections – connections that can actually be built – between various air barrier components. But in my limited experience, it turns out many of the foams – currently and recently in use – lack memory. Shrinkage of the wood framing, coupled with shrinkage of the foam, creates channels through which air funnels and fuels progressive decay.  
    To make an industry problem worse and very personal … as winter settles in I’m feeling the same thing happen in my own home.  

  10. Sitting through the sessions
    Sitting through the sessions was well worth the long flight and Dr. Joe’s hospitality is always better than expected. 
    I was not possessed with the gumption at the time to ask the questions that I think ought to be addressed. 
    There were many references during the day from multiple presenters to spray foam as both a sealant and an air barrier. 
    As a developer of sealants and air barriers and a tester of materials, assemblies and systems, I know sealants are subjected to a variety of tests, ASTM and otherwise, that define their properties as sealants. Elongation, contraction, durometer, adhesion, resistance to temperature, UV and other conditions are measured to determine suitability for various applications. 
    Spray foam is not a sealant, structural or otherwise. 
    Air Barriers are tested to perform at minimal industry standards to determine leakage rates at positive and negative pressures after the assembly has been subjected to a variety of conditions. Better air barriers are subjected to conditions that the structure will likely experience based on it’s geographic location. The Best Air Barriers are tested and perform up to structural failure after seismic, shrinkage and settling effects. 
    Considering we spent the following day at this conference listening to Professor John Straab elaborate on the dysfunction of the HVAC industry and the selection of efficient HVAC and DHW for low load structures, we know how important the air barrier’s long term performance will effect the health and durability of the building. 
    Spray foam is not a structural air barrier. 
    Whether or not spray foam is a suitable material as insulation for high performance structures is worth a dialogue, considering health, environmental and safety issues as well as long term durability, but to suggest it is a sealant or an air barrier should require some proof. 

  11. I just read Tom Schneider’s
    I just read Tom Schneider’s post and had to comment. We have been spraying a heavy density polyurethane based sealant since 2005 and have addressed many of the issues which you describe. We have just recently tested our sealant in the Home Performance/ HVAC industry and have been encouraged enough to start to move forward with additional work. We have a free E-Course ( ) which we point people to in order to have them understand how sealants work as that seems to be the real challenge. To your point in your post, a lot of people understand spray foam and R-Value but they are equating that to performing as a sealant. In my humble opinion, this is where the big technological breakthrough will have to come.

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