Replies

1. GBA Editor
   Martin Holladay | Aug 08, 2014 04:30am | #1

   Reuven,
   Q. "How many builders, retrofit contractors are using AirKrete?"

   A. Not many.

   Q. "What's the catch?"

   A. Limited distribution and availability. High price. Reports that the cured material shrinks and is crumbly. Widespread skepticism concerning the company's R-value claims.

   If you enter "AirKrete" into the GBA search box, you'll get a lot of results. You might want to read:

   AirKrete and moisture

   Does anyone here have direct experience with AirKrete Insulation?

   In an earlier response to a reader's query about AirKrete, I wrote:

   Here is a link to the Environmental Building News article for interested GBA readers: “What About Air Krete?”.

   In that article, author Tristan Roberts notes, "The most striking claim currently being made by Air Krete is that it offers an insulation value of R-6 per inch. That’s pretty high—much higher than the R-3 to R-4 values that we expect from most other building insulation materials.... The only trouble is that Air Krete has used an unorthodox testing method to demonstrate the R-6 result and may even be in violation of Federal Trade Commission rules for how insulation sold to consumers must be tested. Those rules require testing according to one of several ASTM standards, the most commonly used being ASTM C 518-04, “Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus.” Yet Air Krete, whose website trumpets “NEW High R Value of 6.0 per inch makes airkrete insulation the top competitor in insulations,” (sic) has published two test results to back that (dated Oct. 2013, June 2013), with neither one citing any ASTM method.

   "Both tests, by Dynalene Laboratory Services in Pennsylvania, use the “transient line source heat methodology” to show an R-value of 18 for a 3-inch Air Krete sample. The tests were done with a temperature probe designed for testing thermal conductivity of soils and minerals, according to Christopher. Also known as the “heated needle” technique, the probe creates a burst of heat and then measures the rate of transmission of that heat with an adjacent probe. Christopher says that the method is compliant with ASTM standards for testing conductivity of soil and rock, and the company making the probe is working on ASTM approval for insulation, something “we expect momentarily,” he said. ...

   "John Straube, Ph.D., P.Eng., of Building Science Consulting in Waterloo, Ontario, echoed those concerns. Reviewing Air Krete’s older R-value test results showing R-3.7, he told EBN, “That is pretty good, but believable, as it is right on the curve of density-versus-R-value for a wide range of products.” R-6 is hard to believe, says Straube."

2. 
   hudson_valley_gregg | Jul 16, 2017 12:16am | #2

   I talked to the sales rep last week. He said R value of 3.9 / in. No mention of R6.

3. 
   user-7028399 | Jul 16, 2023 03:49pm | #3

   It's sold as 3.9, we just did 3" of it.