All nine buildings at Manhattan’s Grant Houses will be undergoing a major overhaul of their brick exterior walls under a $12,997,717 contract recently awarded by the Board of the New York City Housing Authority (NYCHA).

The contact calls for installation of horizontal expansion joints between every floor of the buildings, which are 13 and 21-stories high. There currently are no expansion joints. Expansion joints allow brick walls to move freely with temperature changes limiting cracks and bulges, which can result in dangerous conditions.

About 20 percent -- some 154,000 square-feet -- of the brickwork will be replaced to install the expansion joints. All existing brickwork will be cleaned.

“This major renovation will leave these buildings looking new, but more importantly, it will enhance the integrity of the structures and increase the level of safety,” NYCHA Chairman Tino Hernandez said.

The contract was awarded to Dobco, Inc., and is expected to take 18 months to complete, once work begins.

Grant Houses, completed September 30, 1957 has 1,940 apartments housing an estimated 4,519 residents. The 15.05-acre complex is between West 123rd and West 125th Streets, Morningside Avenue and Broadway.