Now that I've read it, and I still think it's bullshit. Even though they say (under FAQ section) it will protect your historic home forever.  Hell, that's better than the National register. 

I wouldn't consider this shit without having seen several installations in person, and talking to the owners.  Seems to me that a coating 10x as thick as paint is gonna obscure some historic detail. I dunno what the ASTM test results mean, but wouldn't be surprised if they don't mean anything in this case.

Another question is how long  this fine high quality product has been in use.  What does the BBB know about it, or about the Duboynes (or whoever they are)?

Stick with Sherbet Willies or Binty Moore.

Ralph