Wohlsen reported that $70 million, or 36 percent, of its total revenue in 2011 was generated from green building.

The top 100 list ranks both publicly held and privately held contractors based on construction contracting-specific revenue on projects registered or certified by third-party organizations following environmental, energy savings or sustainability standards.

Wohlsen saw a 25 percent increase in the number of construction projects in its four-state market of Pennsylvania, Delaware, Maryland and New Jersey.

“As a company, we are committed to the advancement, education and success of sustainable practices throughout the construction process,” Gary Langmuir, president and CEO, said in a statement.

Last year, Wohlsen purchased an adjacent property at Steel Way and the Manheim Pike that it renovated and expanded for use as an operations center.

The 18,300-square-foot green facility has open office workstations and a variety of conference rooms to create a more centralized space and improve workflow between departments.

The Keystone Chapter of Associated Builders and Contractors named the operations center Project of the Year.