The eight story Apex Plaza, a mixed use building consisting of the headquarters of Apex Clean Energy as well as residential, and retail space, is the largest mass timber building on the East Coast. The cross-laminated timber (CLT) frame of this 265,000 sf building is sustainably harvested from fast growth timber and sequesters more than 2000 metric tons of CO2. The building's solar array produces more energy than Apex uses, achieving net-zero energy use for the company.