WCEC’s previous envelope sealing tests were successful at effectively sealing over 50% of the available leaks in 2 different homes. The only issue with using the previous sealant was that it retained its stickiness almost indefinitely. This made it much less likely to be used in a retrofit without larger, more involved preparation beforehand. To make this technology more attractive and convenient for contractors to use, WCEC is working with a liquid adhesive manufacturer to help craft a more suitable product. On February 14th, in Stockton California, WCEC tested the new adhesive in another rough-in home provided by Habitat for Humanity.    

How Effective Was this New Formula Adhesive?
Nelson Dichter, one of WCEC’s field engineers confirmed some positive findings, “During the sealing process, I often enter the house to move the injector,” Dichter said. “What I noticed most was that the new adhesive could be easily wiped off my hair and body. Yet in larger clumps where it sealed leaks, the sealant hardened nicely to create a strong seal. The previous sealant was more problematic when moving the injector nozzle because it always remained sticky, and was difficult to clean off of any surface, including me.” Dichter concluded, “This sealant shows great promise.”

“There was one drawback to the new sealant,” said WCEC’s engineer Curtis Harrington, “it took longer to form seals at leak points compared to the previous adhesive.” Harrington continued,“The new sealant definitely took longer to get the house sealed up and required much more of it to fully seal a house. For this test, since we did not have another cannister of the new sealant, we decided to finish up the house with the previous sealant.” Harrington concluded, “We are confident that this particular sealant will only require some minor adjustments to find that balance between tackiness and hardness, to get the best overall seal with the least amount of clean-up time.”

The Next Steps Towards Commercialization
To solve the issue of requiring more sealant to fully seal a house and to dramatically reduce the sealing time, WCEC has developed a new, multi-point injection system. This system uses pressurized nitrogen instead of an air compressor to push the sealant out of the 6 available injection nozzles. This also allows the system to not require as much electrical power since the largest power draw besides the blower door is the air compressor. WCEC will begin real world testing of this system next week in another house provided by Habitat For Humanity. A full write up including results from this promising new technology will be available in WCEC’s next quarterly newsletter.

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