More Product Guide
AeroBarrier has been in the building news quite a bit lately:
- GBA – Aeroseal rolls out air sealing technology for houses
- Fine Homebuilding – New technology improves airtightness
- Journal of Light Construction – A game-changer for airtight construction
How AeroBarrier Works
AeroBarrier is an innovative and sophisticated system for air sealing buildings. During installation, a proprietary synthetic acrylic is aerosolized while the home is under pressure developed by a blower door. As the air leaks through the building enclosure, the latex aerosol sticks and builds up on pretty much any crack up to about ½-inch.
AeroBarrier aerosol head fired up to seal leaks using positive pressure delivered by blower door. Photo courtesy of AeroBarrier.
In under 2 hours, a home can move from leaky to pretty much whatever level of air sealing you are prepared to pay for.
You do, of course, need to prep the building, air sealing pathways larger than ½-inch, but following the Energy Star Thermal Bypass Checklist heavy hitters is straightforward.
You can use AeroBarrier before cavity insulation is installed (essentially completing an exterior air barrier) or after drywall (essentially completing an interior air barrier); in either case requiring pretty limited protection of finished surfaces.
The real beauty to me of the AeroBarrier approach is that it is real-time performance-based. The blower door testing and results is built into the AeroBarrier process.
AeroBarrier in existing buildings
If an existing building is between occupants, there will be protection of more finished surfaces required—and the bigger thermal bypasses still need to be at least “rough” sealed—but that does not seem like that much of a jump from AeroBarrier post-drywall in new construction.
Paul Springer, manager of business development for AeroBarrier, connected me to Mitchell Spence of Redfish Builders, the leading AeroBarrier partner doing existing homes. Springer stated that about 10% of the AeroBarrier partners nationwide work on existing buildings but they do this completely on their own. Springer also noted: “We do have a new grant from the DOE in which we are going to be applying AeroBarrier in finished spaces (non-occupied) to understand the benefits.”
“About 10% of our air sealing business currently is AeroBarrier in existing homes,” says Spence. “The key for us managing the liability of damage to contents is our partnership with a painting company. They know how to rigorously and efficiently seal everything from clothing to furniture to floor coverings and we know how to seal the building.”
Spence feels the other key to his AeroBarrier work is his background in high performance building at Redfish. It’s his knowledge of the building process and business partnerships with trade contractors and other builders that means AeroBarrier work on new production homes, new custom homes, existing homes, and multi-family projects.
Spence has tuned his air sealing of existing buildings with AeroBarrier. “I pretty routinely suit up with respiratory protection to first target my Retrotec fogger at suspected leaky areas and then relocate the AeroBarrier spray heads to target those leaks. I also use “first sweep” during AeroBarrier air sealing, brushing off aerosol that is going after surface leaks encouraging aerosol sealing a bit deeper into existing building assemblies.” Spence also noted that quite a bit of the prep for holes and cracks larger than ½-inch gets addressed with closed-cell backer rod, which costs about $100 for a 500 foot roll off of Amazon.
The following images are various types of prep completed by Mitchell Spence’s painting contractor in occupied existing projects.
Spence is a big advocate of AeroBarrier for multi-family air sealing. “We can do unit-by-unit AeroBarrier work, not only sealing the building enclosure but between units. This has big indoor air quality and sound transmission benefits,” says Spence.
How AeroBarrier in existing buildings could be a game changer
Increasingly, as I do assessments and investigations of existing buildings, performance concerns of the building owners are rooted in air leakage, from comfort complaints to more serious moisture issues. And those same clients often have questions and concerns regarding spray foam as pretty much the only game in town for seriously improving the airtightness of existing buildings.
I think that AeroBarrier in existing buildings can give spray foam a real run for its money in many of the 100+ million existing dwelling units we have in the US. An aggressive and elastic yet largely benign acrylic aerosol (see AeroBarrier MSDS) could be just what our existing building stock needs to safely improve the toughest aspect of existing building performance: airtightness.
But how much does it cost?
Spence told me that for occupied homes AeroBarrier runs between $3 and $4.25 per square foot of building but it makes a big difference what type of building. “Large custom homes can be up to $7 per square foot including both prep and AeroBarrier process,” says Spence.
What do you think?
Peter Yost is GBA’s technical director. He is also the founder of a consulting company in Brattleboro, Vermont, called Building-Wright. He routinely consults on the design and construction of both new homes and retrofit projects. He has been building, researching, teaching, writing, and consulting on high-performance homes for more than twenty years, and he’s been recognized as NAHB Educator of the Year. Do you have a building science puzzle? Contact Pete here.
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41 Comments
I like the idea but I wonder it it's any less resilient with regards to daily thermal expansion and customary settling of the structure itself.
I think of it as an interior applied liquid WRB.
Hi John -
Big concern of mine too is the service life of AeroBarrier as an air sealing method. I do like the fact that the "sticky stuff" is acrylic, since in my testing of PSA tapes, acrylic adhesives fared the best with lots of different substrates and cold and wet as well as hot and dry.
There has been a lot of research on AeroBarrier and longitudinal testing by Dave Bohac at CEE in Minnesota and my understanding is that sustained performance has been good, at least for some years.
I also know that Steve Baczek and Jake Bruton have a couple or so of Jake's homes that have/will get the AeroBarrier system and Jake is going to be blower-door testing these homes over time.
Peter
I'm not sure about existing homes, but this makes zero sense for new construction. Just design the house properly, and pay attention to details while you build it and <1.5ACH is very easy. A 2500 square foot home would cost between $7500 and $10,600 using Aerobarrier. There's no way you'd spend close to that much using taping, etc. The only scenario this makes sense for is if you realised part way into construction that you forgot (or hadn't yet learned the importance of) air sealing details, or at blower door testing stage you found out some of your subs didn't do their jobs; a last resort to fix a big "whoopsie". Not as a primary means of air sealing. Planning on Aerobarrier from the start is like installing tires on rims without sealing the rims to the tires and using "fix-a-flat" when you inflate them.
The cost for existing homes is indeed daunting. Even spending the same amount of money on rooftop PV is likely to have a better net energy ROI.
Interesting Dana.
It did not occur to me to compare PV and air sealing based on ROI because a big part of air sealing existing homes to me is about thermal comfort, indoor air quality, durability, moisture management.
Peter
The cost in the article is for occupied homes, new construction is quite a bit cheaper (I just did this on my project).
I must say you're living in a bubble if you think that getting under 1.5 ACH50 is "very easy" for a huge number of builders in this country (who aren't reading GBA and have never used tape). The real potential for AeroBarrier is that market, not us GBA dorks! :D
These aeroseal people are like vultures, they trawl the internet and anytime someone mentions them or a concept close enough they show up to hawk their wares. And then the grandiose claims, then the arguing with anyone who disagrees with them, its like a messed up evolutionary offshoot of multi level marketing.
If anyone even asks about the toxicity or durability its likely they will show up and start spamming us. Though i hope this forewarning will keep them away.
All that said it would be far cheaper to hire a blower door tech, find all the leakage vectors you can, list or photograph them, seal them, repeat and seal more if necessary. I don't know what the going price for a blower door test and letting it run for 15 minutes is but i imagine its vastly cheaper.
If your walls and ceilings are made of mesh screens instead of solid matter then aeroseal may be your best option though it will have no R value, just air sealing value.
The testing has been done. VOC emissions and long term durability. Its as advertised.
If this sealing process is continued long enough, does it result in a 100% sealed building with no leakage whatsoever?
Depends on what you mean by 100%. Percentages of what starting point, and how many signficant digits of accuracy?
There is no absolute zero of air leakage the way there is with temperature. Even hermetically sealed enclosures for space grade microchips will pass some amount of helium, and are thus arguably not 100% sealed.
From an energy and ventilation point of view the ~50 cfm/50 after 135 minutes shown in the graph is tight enough to be considered "as good as 100%" from a practical point of view. At that level of tightness energy and moisture impacts are WAY down "in the noise" of other building factors in a house.
Ron,
If they could get below 0.05 ACH @ 50 pascals, it would be the tightest house in the world
https://zeroenergyproject.org/2014/08/10/the-worlds-most-air-tight-home-0-05-ach50-pascals/
A house I designed, built by Emerald Builders in Bowdoinham, Maine, shell tested at 0.12 ACH50. That's with no sprayed foam, just double-stud walls with cellulose and meticulous taping using Pro Clima products. I have a hard time seeing where Aerobarrier makes sense.
Michael,
The only way I can see it making sense is if it completely displaces other methods of air-sealing and becomes the accepted industry norm. For that to happen the price would have to come down substantially - and I don't know if that's possible.
I think they want to preserve their margins.
It might make sense for homeowners who don’t have time to become green building gurus and whose builders aren’t conscientious about green building techniques. It can make up for a lot of stupid. I’m sure you didn’t just accidentally build a house that air-tight.
You make it sound like installing pro clima products is a walk in the park - or that the pro clima system is cost effective. Its expensive, its incredibly labor intensive to install and hard to ensure performance after sheetrock is installed. Everyone drinking the 475 koolaid needs to pump the brakes and accept that fact there are alternatives to the products and concepts 475 sells / markets and promotes. Aero barrier offers a cost effective approach to achieving low ACH performance without ensuring that every trade on a job site will follow through with their promise to put tape on any hole they create. There is room in the market for more than the 475 membrane and tape system for high performance homes. And yes, even room for spray applied foam. The more options available, the better for the performance of our buildings.
JohnP123, I think I've tried every method out there at this point (except Aerobarrier) and I am not loyal to 475 or Pro Clima. But they have a good system that I've spec'd and or used myself many times and it's not that hard to do. Certainly less than spending $10K on Aerobarrier. But it does require some education. I don't expect subs to learn or care about building airtight; that's the GC's job. The tightest house I've done with spray foam was 1.7 ACH50. I thought it was good at the time, but it's not really.
“[Deleted]”
Reality check on cost: I just did AeroBarrier on a small home here in Seattle (new construction, before insulation) and it was about $1.40/ square foot of floor area. Obviously this varies based on a lot of factors including what dealer you're using, but it's one data point.
ICF houses are typically in the 0.25 ACH range without a lot of extra work. All walls ICF and roof using advanced wood framing techniques.
So I want to leave a little perspective on my recent Aerobarrier experience. It was on a major remodel (down to studs) of existing home. I used it to supplement my own exterior air barrier. I put forth a pretty good effort with caulk, foam, and taping sheathing, but could still only get to 3ACH50. There were some limitations in a remodel situation regardless that would not exist with good planning in new construction, and I am sure I could do better next time if I kept doing this kind of thing.
I negotiated 2.19 per SF in Bay Area for a 2000 sf home, though they knew I was doing my own air sealing ahead of time, and my situation was closer to new construction for them. They got me to 0.22ACH50. Of course, I had to take a couple of days off work since my GC wouldn't airseal beyond taping the sheathing. So you could say I paid for it one way or another. I worked with Western Aerobarrier and they were great, but I also had a great conversation with SDI insulation which is Bay Area based.
Certainly, where I live it was not "cost effective" to use Aerobarrier when I was already at 3ACH50. I hope this will become cheaper as it is scaled up. I think there are a lot of situations where it is difficult, for a variety of reasons, for a homeowner to get a tight house and this is one solution, albeit at a high cost.
When my house was being Aerosealed, it seemed like 0.2ACH50 was the asymptote for my house and that no matter how much longer we continued, it would not get any tighter. Later I found one large hole that had been missed during my own air sealing, around 1.5" sq, and the Aerobarrier hadn't filled it in at all. So maybe the theoretical max of house is less than 0.2, but there seems to be a limit to what it can do.
Asaf
Thanks Asaf, that's interesting to hear.
Is that 0.2ACH50 measured during the Aeroseal process with windows and ducts taped?
Thanks,
Cory
Cory,
That is an important clarification you made. This is the airtightness during the air sealing process so windows door and ducts taped. This is also pre-dense packed cellulose and drywall in my case. So not the “true” number yet and provided by the AeroBarrier technology. In a few months I’ll report here the final Ach50 from blower door when house is complete. As the ducting has been well sealed, It may give me some insight also as to how leaky these Integrity windows are.
Thanks Asaf,
It will certainly be interesting to compare the numbers from different stages of the build. Best of luck with your build.
Cory
Thanks much for sharing this Asaf.
Though we could not get this set up in time for this blog, I am very much hoping to get our home AeroBarrier-ed. I am at about 4 ACH50 after a 12-year, room-by-room deep energy retrofit (https://www.greenbuildingadvisor.com/green-homes/deep-energy-makeover-one-step-at-a-time) and I don't really feel that I can get to many or most of the remaining thermal bypasses.
I very much want to see the existing, occupied, AeroBarrier up front and personal, and to track by IR and fogging exactly where and how the air leaks get addressed by AB.
Hearing your experience is really helpful.
Peter
I'm a curious consumer interested in green building with low knowledge of how all of this works. What strikes me about the AeroBarrier methodology is the potential to increase the air tightness of existing homes.
The following scenario runs through my head. What if states implemented programs that required increased air sealing on homes when they sell? The AeroBarrier method could be used when the home is empty between people moving out and the next folk moving in. That would reduce the cost of having to seal furniture and and all the other items in a house that's being lived in. Perhaps states could offer a rebate for the work. Here in Oregon I could see Energy Trust of Oregon getting involved to help facilitate the program. I can envision power companies becoming involved too. If currently leaky houses are tighter then that is better for the long-term reduction of power that utilities have to produce.
Plenty of older houses sell every day that were built before air sealing technology advanced to the point where it is today.
Not regular construction, and not existing housing.:We did a MODULAR home. Our mostly finished 4-box 2-story started at 3.06ACH50, and ended at 1.08ACH50 170 minutes later. See attached Report. The curve indicates the constant buildup of sealant as the installation reached diminishing returns.
Ironically, there was a missing piece of drywall discovered behind our 2nd floor air handler, and our AB tech explained that patching that would get us well below 1ACH. Which also tells me we would have been well below 3ACH from the gitgo - which is code required in Maryland.
What we learned:
1. This confirmed what we've known for years: modular/prefab construction is inherently tighter because modules (boxes) are built inside out in a controlled environment.
2. Our 2-story on full basement and pulldown ladder to unfinished attic was pretty damned tight before AB, even before we patched a drywall hole in a mech. closet.
3. New-to-modular contractors that forget to foam-seal the marriage floors/walls/ceilings (where boxes come together) before closing in can definitely save their skins with AeroBarrier.
The concept sounds appealing, however I have some concern about aerosolizing all these particles throughout the entire house. Obvy if the particles stick to the walls of the leaky spots, they will stick pretty much everywhere else too.
My biggest concern though, is that of resilience. It stands to reason that the particles will build up only until the hole is sealed, but then no more. Thus, there will be "just enough" to fill the leaky spot, but maybe (probably?) not enough to last for the long haul (maybe a few years?) IMO... it's been too short a time for adequate "longevity" testing to have been performed, so we really have no way of knowing how long this air sealing option will last. Whereas we do know that if we liberally apply a flexible acrylic caulk, it will last many decades, barring any major movement of the building structure of course.
If Aerobarrier is confident that their system will last for the long haul, I'd like to see a commitment to this end. I.e., some sort of written guarantee that they will come out for free and pressure test the house again after a decade, and if the product has not stood the test of time, they will visually inspect various areas that were treated with the customer to verify if they have degraded or separated, and if so, they will give a pro-rated portion of the initial costs back to the customer. If they are confident enough in their product, this should not be an issue to implement., especially at current costs.
My final concerns are that of product waste, and potential air contamination of adjacent properties. These "particles" will be released en-masse, so there will potentially be a huge waste associated with this method (possibly part of the reason for such a high cost), and, these particles will filter through the air leaks contaminating the surrounding air to some extent... can't be good to breath this stuff in. That being said, unfortunately, there are always plenty of nuisance and/or toxic dusts floating around construction sites. But do we need more?
I just got a quote of $2,850 to install this in a new custom home of 2,450 s.f. to meet .6 ACH50 in San Diego. It's a modern, wood-framed home with an average number of openings. That's $1.16 per s.f. which I think is a great deal compared to absolutely every other price I got on the entire house in these crazy times (May 2021). My contractor has never built an envelope that got tested so I think this is a good backup to all of the other air sealing that is planned. I can't afford to build it right now but thought I would report on the current pricing.
Too many loose ends in that product for me. I can't imagine loosing a new chemical indiscriminately throughout my house and having it stick to everything? Maybe I am old-fashioned but I had a cousin who was a Thalidomide baby in the 1950s. I read Tom's River (won the Pulitzer for non-fiction in 2014) about the chemical company Ciba-Geigy that caused so much cancer on the Tom's River in NJ and then morphed into Novartis, the 'healthcare company'. That company absolutely knew what was happening decades before they shut that operation down. Read the book.
I am not saying Aerobarrier is going to cause cancer. I am saying that the more modern chemicals we are exposed to the greater our risk. I think modern society is way to free with chemicals. Aerobarrier will be there from now on interacting with every chemical that is in the environment and I imagine somebody will say, it is inert. Well, everything reacts. Why not make the house design a little simpler and put some people to work with time tested sealers, tapes, and caulkings (as best you can) and live with a little less perfection and little more health.
I have a friend who wrote prescriptions for removing asbestos (another miracle product) from buildings. Made quite a bit of money for a few years. Then got so scared about his personal liability that he spent the money becoming a lawyer, so he could defend himself.
I guess this is a rant but I live by choice where the quality of air is very good (except for the occasional dirt storm...windy). Over 100,000 Americans die from air pollution every year and most people have no idea how unhealthy their personal air is and that there is any such thing as fairly clean air. Ciba-Geigy changed their name to Novartis and moved on with dollars in their pockets.
Sorry for the rant and maybe I am wrong. If my rant was inappropriate I won't do it again. But, this is supposed to be a green building forum.
SierraWayfarer, I share your wariness when it comes to new products that could have health or environmental implications and generally don't trust corporations to do the right thing. I have not used Aerobarrier yet but have been paying attention to articles and conversations about it. This information, from one of their franchisees' websites, gives me some confidence--from what I understand it's not particularly easy to get Greenguard Gold certified or for the product and its ingredients to be declared redlist-free:
› GreenGuard Gold certified
› No off-gassing
› Withstands 50-year durability tests with virtually no degradation or loss of seal
› Meets the strictest certification requirements for use in schools and hospitals
› Non-flammable
› Red List Free*
*AeroBarrier contains no ingredients or components from the ILFI Red List of building materials
(https://aerobarrierwest.com/what-is-aerobarrier/)
Michael,
I think the biggest problem is it is counterintuitive. Our experience tells us when you indiscriminately spray something into the air it covers every surface. It's hard to get your head around it only ending up where you want it.
Hi Malcolm,
You said, "It's hard to get your head around it only ending up where you want it." I looked through all five of the company's 'technical documents'. I didn't see it anything about it only plugging holes and not sticking to anything else. It won't take you long to look. Not much in them except the Safety Data Sheet. https://aerobarrierwest.com/technical-library/
In the technical documents most of them basically stated that it 'plugged up holes'. I have attached the material safety data sheet. At the very end it says:
---------------------------
For Industrial Use Only. Keep out of Reach of Children. The hazard information herein is offered solely for the consideration of the user, subject to their own investigation of compliance with applicable regulations, including the safe use of the product under every foreseeable condition.
---------------------------
Which basically says: 'we are NOT RESPONSIBLE for the chemical safety of this product'.
Who is responsible, the chemically ignorant and stupid 99.9% of the world?
SierraWayfarer,
I meant that as a possible explanation for why people may be reticent to adopt it, not to in any way diminish the validity of your concerns about its possible effects on health - which I know n0thing about.
Hi Michael,
GreenGuard Gold Certification from the UL site mostly says: GREENGUARD Gold Certified products must also comply with requirements of the state of California Department of Public Health (CDPH) Standard Method for the Testing and Evaluation of Volatile Organic Chemical Emissions from Indoor Sources Using Environmental Chambers,(also known as California Section 01350).
The word GREEN is very much becoming coopted. This is not a proven GREEN product. Not until it has a long history of safety. Shame on UL.
If you look in the material safety data sheet you see:
US. California Proposition 65This product contains chemical(s) known to the State of California to cause cancer and/or to cause birth defects or other reproductive harm.MethanolDevelopmental toxin. 03 2012Ethyl AcrylateCarcinogenic. 09 2011FormaldehydeCarcinogenic. 09 2011
The AeroBarrier data sheet says it is the user and not the company that is responsible for "the safe use of the product under every foreseeable condition". Fine lawyer talk...
I know I can't stop 'progress'. All I can do is to try to avoid being a victim of it...
As I understand it, California has a unique system wherein everything is considered "proven to cause cancer" unless it can be proven that it doesn't cause cancer, which can be nearly impossible to prove. I agree that "green" is a compromised word at this point, but Greenguard certification is generally respected, and Redlist-free is even more highly respected in the "green" design/build world. I'm not saying I'm 100% on board with the product, but chemical names and California cancer rules don't scare me much.
Unfortunately the prop 65 requirements (and companies being afraid of litigation) mean the label is basically meaningless -- your product could be completely inert cube with a milliliter of whiskey in the middle ("alcoholic beverages" are listed chemicals), or a pillow made from a lead-cadmium alloy stuffed with asbestos, and they'd both get a prop65 warning label. Obviously there's a spectrum of risk exposure, and I'm sure part of the point of the program is to incentivize companies to stop using any of the listed substances, but from a consumer standpoint when nearly everything ends up with one of these labels, it's nearly useless for assessing actual risk exposure and making informed purchasing decision.
Finally, I know this could save an awful lot of labor and since it is applied only to the 'air barrier' before the inside or outside is finished it won't have much contact with people's skin and it apparently doesn't off gas bad. Its probably safe. But it is that word probably and this is just one of many 1000s of unproven chemicals in our environment.
I guess I am over reacting to being a lab rat but we all are.
SierraWF,
I don't have a need for Aerobarrier in my finished home and if I was building a new home it is unlikely I would contract AB to do any air sealing. The last thing I want to do is schedule an additional contractor, just to spray rubberized dust particles. I can air seal, I can teach people how to air seal with other methods.
Another thought, I'm shocked at how many new homes are constructed with full Zip system sheathing and them insulated with closed cell spray foam. Aerobarrier is barely noticeable is this nightmare you portray.
Hi James,
Yeah, I wonder about all of the foam. I am glad that I don't think it will be necessary in my new home. I also wonder if I might be a bit of a Luddite.
You alluded to the 'Nightmare I portray'........ Definitely there are a lot of chemicals and perhaps more importantly chemical interactions that we don't understand the long term consequences of. I think most of it will be a benefit but as one is discovered as harmful we study it, fence it off, and provide what help we can to those who suffered.
Our knowledge base is growing.
I am little embarrassed that I displayed and continue to display my lack of understanding of 'a perhaps necessary inadvertant sort-of-accidental worldwide chemical experiment' with all of us as the 'lab rats'. I need to go read but there is so much to read, to understand. I just googled 'chemicals in our environment'. The second link led too: https://chemical-free-life.org/
Sadly, or perhaps its a good thing, I and most of us have a lot to learn.
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