It all started when...
The ASTM C90 standard changed from requiring 2.25 in/ft minimum equivalent web thickness to requiring 6.5 in2/ft2 normalized web area in standard concrete masonry units. What followed was a 6 year design genesis that has resulted in a full line of concrete masonry units that are a patented redesign of an A-shaped, open ended CMU. The design of the original ProBlock along with the logo, marketing literature, and even the website has matured along with the engineering behind it.
