Cyclists from Bike and Build, a cross-country bicycle trip that benefits affordable housing groups, nail down the roof of a Habitat for Humanity home Thursday at 203 N. Comfort Lane. Exactly 31 volunteers pedaled into Lawrence on a 4,300-mile journey from Providence, R.I., to San Francisco, stopping to help build affordable housing.

Mike Benson, of New Milford, Conn., nails down part of the roof of a Habitat for Humanity home Thursday at 203 N. Comfort Lane in North Lawrence. Benson is part of the Bike and Build trip from Providence, R.I., to San Francisco.

A group of bikers rolled into Lawrence on Thursday to help build a Habitat for Humanity home. They’re going coast to coast on two wheels as part of Bike and Build.

The home, in the Comfort Neighborhood in North Lawrence, is the latest project for the group. For 72 days, they’ll travel about 4,300 miles from Providence, R.I., to San Francisco.

And while it might be a long ride, those involved seem to enjoy it.

“I love biking and seeing new places,” said Harvard student Grace Hollowell, a 19-year-old from Ann Arbor, Mich.

The group feels as if they have the opportunity to leave their mark on each community they see.

“The hospitality has been amazing everywhere we’ve gone,” said Dustin Wall, a 24-year-old from North Bay, Ontario. His favorite part of the cross-country trip is “feeling that we’re making a difference and being a part of these various communities we stop at.”

The group of 31 started June 2 and should arrive in California on Aug. 12. And while they may be biking the entire way, that doesn’t mean they are necessarily professional cyclists.

Colin Hunt, a 22-year-old Mahopac, N.Y., native, used his bike to get around, but riding 103 miles from Missouri to Kansas was something new.

“It was an experience,” he said. “It’s definitely an accomplishment, something that feels good when you finally complete it.”

The riders are in one of seven groups biking and building homes around the country on different routes east to west, and the Providence to San Francisco group is enjoying the Midwest.

“I’ve never been to the Midwest,” Wall said. “And I’m loving it.”

The people they’ve meet have also made a difference in their experience.

“Everybody’s been really nice and helpful,” Hunt said. “They open up when you’re doing a cause like this.”

The cyclists have been staying in churches and YMCAs across the country. But while in Lawrence, they have complimentary lodging at Spring Hill Suites.

They will leave Lawrence at 6 a.m. Saturday to head to Manhattan, where they will stop on their way to their next build, which is in Colorado.