For 50 city volunteers, Martin Luther King, Jr. Day was spent constructing houses in 30-degree weather for two disadvantaged families.

Monday’s second annual “Building on the Dream” Habitat for Humanity ceremony was the inaugural event at the new Dixwell-Yale University Community Learning Center. Following an early-morning remembrance ceremony led by Dr. Bonita Grubs, executive director of the social services agency Christian Community Action, the volunteers spent three hours working on two Habitat houses in the Newhallville neighborhood and discussing King’s legacy.

“The event was meant to be symbolic in the sense that people should be volunteering all year round, every day, and should be thinking about community involvement in terms of Dr. King’s message and the vision he promoted,” said Jonathan Schmidt ’96 LAW ’03, chair of Habitat for Humanity’s development committee and coordinator of the event.

After the morning’s construction work, volunteers joined a discussion reflecting on King’s life as well as issues of homelessness and affordable housing.

Habitat for Humanity of Greater New Haven, which is celebrating its 20th anniversary this year, has built 48 houses in the city, concentrating its efforts in Newhallville and the city’s Hill area. Executive Director Bill Casey said the organization focuses its rehabilitation of abandoned or dilapidated houses to foster community development throughout larger neighborhoods.

“We’ve seen a spinoff, where the neighbors of our redeveloped homes start taking more pride in their houses and improve their properties on their own,” Casey said. “It’s hard to continue taking pride in your property if there’s an abandoned house right across the street.”

Schmidt said that Habitat’s rehabilitation of nine or 10 houses within a three-block radius in Newhallville has had its intended effect.

“By concentrating the redevelopment, you begin to not just change a family’s life or an abandoned structure, but you begin to change a neighborhood as well,” he said.

Recipients of Habitat for Humanity aid must meet three criteria, Casey said. Habitat homeowners earn between 30 and 60 percent of the national median income — between $20,000 and $40,000 annually for a family of four. Homeowners also have a demonstrated need for housing, living in substandard housing conditions or in very dangerous neighborhoods, and must be willing to formally partner with the organization, which requires a 400-hour commitment to building their house and an agreement to participate in Habitat fundraising efforts.

The cost of a Habitat-constructed house to a family is significantly lower than most market-rental prices around the city. Schmidt said mortgage and taxes for Habitat houses cost approximately $350 per month for most families, versus an average of $500 in monthly apartment rent.

“It’s very empowering,” Schmidt said. “These families are becoming average homeowners, paying a mortgage just like everyone else, and they’re able to get out of the cycle [of high housing costs] that keeps them from accruing savings and getting ahead.”

While Casey said recent rises in housing costs around New Haven and higher oil prices have not increased Habitat’s demand for home rehabilitation, he said the organization is facing a bigger problem, as acquiring property for redevelopment is becoming more expensive.

“We have to be careful of getting priced out of the market, as has happened to other Habitat chapters around the country,” he said.

Yale’s involvement with the New Haven chapter of Habitat for Humanity dates back more than a decade. Casey said Yale’s annual Habitat Bicycle Challenge, supervised and organized entirely by students, is the single biggest fundraiser of any Habitat chapter in the country.

Amy Wojnarwsky ’07, senior advisor to the Yale Hunger and Homelessness Action Project, said Yale students coordinated a related event at the Peabody Museum throughout the day, assisting children at the museum in creating housewarming art for the two families receiving the homes.