Baltimore-based Williams Scotsman Inc. said yesterday it has signed an agreement to acquire Honolulu-based Hawaii Modular Space and its sister company, Alaska Modular Space.

Williams Scotsman said it will pay $42.5 million for the companies, and make additional payments totaling $3 million if the companies achieve certain financial targets.

Hawaii Modular operates three branch locations across the state, while Alaska Modular manages operations based in Anchorage. The assets being purchased include 1,300 mobile offices, storage containers, classrooms and custom modular buildings.

"With one of the fastest growing economies in the United States, Hawai'i offers an attractive venue for the expansion of Williams Scotsman's market presence and business model." Williams Scotsman said in a news release.

"Hawaii Modular's customer base, products and services, and overall market position represent a well developed operation with sustainable competitive advantage," the company said.