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GPG OUTBRIEF 30
Automated Building Envelope Sealing
If you missed our latest webinar on a Green Proving Ground (GPG) assessment of automated building envelope sealing, a recording of the webinar and presentation slides are now available.
Many thanks to the presenters and participants for their thoughtful questions, some of which are answered below:
Q: If the aerosol product seals up to 1/2 inch diameter, how does it avoid sealing weep holes in the building enclosure for drainage?
A: Cover all the openings you don't want to be sealed. If there is a pressure difference between the exterior and interior, the sealant will migrate to the hole. Weep holes will need to be sealed from the outside. The vendor reports that in their experience with brick masonry, the product has sealed the first layer of leakage inside the space without sealing the weep hole to the exterior.
Q: Is there any build-up of the material on surfaces that would later need to be treated (i.e., painted) or cleaned up?
A: The sealant will only adhere to horizontal services such as flooring and countertops. Vertical surfaces should not be affected unless there is a penetration/hole the sealant is sealing. The sealant is emitted as a “fine” mist in small particle sizes (3 microns) for easy cleanup.
Q: What is the warranty? Are there any concerns related to cleaning chemicals that may affect the sealant?
A: 15-year warranty. Vendor estimates a 50-year lifespan. The sealant is predominantly acrylic polymer (typical construction acrylic-based caulk). Natural cleaning agents diluted with water are fine for cleanup. Refrain from using abrasive scrubbers. The residue can be removed with a paper towel or cloth.
Q. Has this product been used on a historical brick building (typical wall make-up from exterior to interior: exterior brick, air gap, interior brick, wood furring, and plaster)? If so, what were the results?
A: Yes, the technology has been used in historical preservation projects with brick exposure on the interior. The project met air leakage reduction goals by treating the exposed interior brick wall, without using spray foam or other sealants.
Q: What impact is there on fire safety and the spread of fire?
A: The Aerobarrier technology evaluated meets the National Fire Protection Association (NFPA) 285 standard: Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Wall Assemblies Containing Combustible Components.
Q: Can you seal one room/zone at a time, or does it have to be the whole building?
A: You can seal separate spaces, but you will have to build an enclosure if you are sealing zone-by-zone or floor-by-floor. From a cost-savings perspective, a whole-building approach may have a better return on investment.
Q: What are the largest volumes that can be practically sealed this way?
A: The technology can scale as needed by adding sealing stations.
Q: Was there a simulation performed for a hot, humid climate? Something like 2A (Austin, San Antonio, or Houston).
A: We have modeled savings across climate zones, and we've seen that the highest savings are in cooler climates with higher heating loads.
Q: Can you use this technique in an occupied building? Would we have to move tenants out of the space?
A: It can be applied to occupied buildings, but it requires additional prep work to move furniture and cover all horizontal surfaces. It will, therefore, be more expensive: $1.75/sq ft vs. $0.90-$1/sq ft for new construction. Space can be re-entered within 30 minutes of sealing.
Q: How long did the sealing take? Does it take multiple sealing efforts to seal a large building?
A: 2 hours and 10 minutes. Sealing is completed with one pass and results are verified at completion.
Q: For an existing building, would you want to do an air barrier test early on to confirm major holes or leaks so those could be accounted for in the design?
A: Yes. Air leakage testing via a blower door test is mandated for residential buildings. We also recommend this for commercial buildings. GSA’s P100 has required blower door testing (ASTM E779) since 2010. Conducting a hygrothermal analysis is recommended to anticipate and mitigate any inadvertent changes in the dew point within the enclosure assembly.
Q: Is there any additional research on this technology?
Q: Are you recommending air sealing with this method for ductwork as well as for the building envelope?
A: GPG is currently evaluating the in-duct solution, and results will be ready within 2 years.
Q: Is the automated air sealing technology that was evaluated commercially available?
A: Yes. The automated air sealing technology we evaluated was provided by Aeroseal. For more information, contact the manufacturer directly: mike.lyon@aeroseal.com
Reference to any specific commercial product, process, or service does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
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The Center for Emerging Building Technologies’ three programs — Green Proving Ground (GPG), Pilot to Portfolio (P2P), and Applied Innovation Learning Lab (AILL) — enable GSA to make sound investment decisions in next-generation building technologies based on their real-world performance.
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