India, May 16 -- Eagle Materials Inc. (EXP), a maker of construction products, said on Friday that its subsidiary, American Gypsum Company, has finalized plans to expand and modernize its Duke, Oklahoma, gypsum wallboard plant. The total project investment is estimated to be $330 million.

Upon completion, the project will increase the plant's annual wallboard manufacturing capacity by 300 million square feet, or 25%, to around 1.5 billion square feet. With moderate additional investment in the future, this project will also enable a further 500 million square feet of capacity expansion, for a total of 2 billion square feet of manufacturing capacity.

The upgraded facility will boost operating efficiencies and reduce natural gas usage, resu...