Realty Development Assoc., a firm that builds modular homes throughout Southeastern Massachusetts and Cape Cod, celebrated its 20th anniversary with a ceremony at its Sagamore office last week.

Company President and founder Don Shulman, a Marstons Mills resident, was recognized by the Massachusetts House of Representatives and Senate, Bourne’s Selectmen’s office and the Cape Cod Canal Region Chamber of Commerce.

Shulman received a citation from the Massachusetts House of Representatives commending the company for its 20 years in business. The company also received a letter and a citation from Massachusetts Senate President Therese Murray.

Last year, the firm opened a second model home/office in Norton to complement its headquarters in Sagamore. RDA also recently announced that it will be developing a 25-lot modular subdivision, The Trails of Plymouth, off Route 3.

The 20-person firm hosts ongoing open houses and seminars on modular construction.

Realty Development Assoc. works exclusively with its factory partner, Westchester Modular Homes, the Wingdale, N.Y. plant that physically constructs the parts to the buildings and then ships them to the site.