A coal fire power generating facility decided to make design changes to lower emissions. The concrete stack was 200 feet tall and tapered in diameter from a base of 25 feet to 20 feet at the top. The entire stack was coated with semi-rigid protective membrane. The structural repair engineer designed carbon fiber laminates, installed externally, to reinforce the new openings and access equipment. The design of the concrete retrofit required modifications to the stacks, including 4 penetrations that ultimately compromise structural integrity. A carbon fiber repair to the stacks restores the structures’ designed architectural performance capability. The structural repair process made use of an existing access platform and exterior elevator which provides ingress from the ground to the platform.