This lumber has been pressure treated for critical structural (CS) applications, such as posts for post frame buildings, decks, porches, pavilions, pergolas, and gazebos. Critical structural treatment significantly outperforms wood treated to ground contact end use. This timber can be completely buried in the ground or submerged in fresh water. AC2® brand treated wood products use MicroPro® technology, which is a revolutionary way to pressure treat wood for decks, fences, landscaping, and general construction uses.