By Claire McNeill | Globe Correspondent August 06, 2014

Sally Snowman still wears her colonial bonnet, but now it is topped with a hard hat.

The lighthouse keeper’s routine has changed with this summer’s renovation on Little Brewster Island, a rocky outer harbor island about 8 miles from Boston. Instead of regaling visitors with tales of Boston Light, the country’s first and oldest continually staffed light station, she dodges piles of cedar shingles and bakes snickerdoodles for contractors camping out on the 3-acre island, which shrinks to just 1.5 acres at high tide.

Scaffolding has swallowed the 89-foot lighthouse tower, rebuilt in 1783 after the British blew up the 1716 rubblestone tower in the Revolutionary War. Centuries of use and exposure to the elements took their toll on Boston Light and the surrounding buildings, spurring a Coast Guard-funded facelift that will total about $2 million by the time renovations conclude next year.

All the work leads up to the lighthouse’s tricentennial celebration in 2016.

“It existed before our country was established,” said Snowman, Boston Light’s 70th keeper and the first woman to hold the job. “We precede the US government. . . . It’s a way of life that doesn’t exist anymore, but we’re doing it in 2014.”

This summer, workers are refreshing the mortar that binds the granite blocks of the lighthouse and resealing it while the island is closed to visitors. Outlying buildings, such as the keeper’s house and the fog signal building, are getting new windows, fresh white paint, cedar shingles, and updated siding.

These long-overdue renovations, underway from May to late September with more to come, are more extensive than other updates in the last few decades.

“It’s something for the city of Boston and for this local area, it’s for the state of Massachusetts, it’s for New England, it’s for the maritime community, and it’s for the Coast Guard, so we really think of it as an investment we had to make,” Commander Marc Knowlton of the US Coast Guard said.

When it was built three hundred years ago, the lighthouse with its welcoming candlelit beacon was meant to keep ships from crashing on the outer harbor islands, as they often did.

“If you want to symbolize hope or safety or protection, people use that icon of a lighthouse, and in particular, they use Boston Light,” Knowlton said. “And to us, it symbolizes our history, our trade, in the Coast Guard.”

In 1989, Senator Edward M. Kennedy extolled Boston Light’s historic value, leading Congress to order that the lighthouse be permanently staffed and made available for public enjoyment. Already a National Historic Landmark, Boston Light became part of the National Park Service’s Boston Harbor Island Recreation Area in 1996.

On a clear night, the lighthouse’s automated crystal beacon cuts 27 miles through the darkness out to sea. Its 1859 Fresnel lens, imported from France, is at the top of 76 iron spiral stairs and holds 336 prisms.

Knowlton compares the lighthouse’s enduring importance and gesture of invitation to the Statue of Liberty. For those in the Coast Guard, he said, it is like seeing history.

“Once you go out there and you start to think about what Boston Light is and what it means to this area, you can’t help but fall in love with it,” he said.

Snowman, who got her job in 2003 when the Coast Guard opened the position to civilians, wants to preserve the lost art of lighthouse-keeping. She splits her time between Weymouth and the island, where she stays Monday through Thursday — though that often slides into continuous weeks in the flurry of the summer months.

She loves the solitude, but summons her energy for the 3,000 annual visitors who come bearing questions about the lighthouse and her life on the rocky outcropping.

Snowman felt the pull of Boston Light when she was a young girl, the harbor as her backyard, declaring she would be married on the island one day. In 1994, she was. Now, she lives in her keeper’s house, built in 1884, with white paint and green trim, in the briny harbor air. Her husband, who works as an assistant keeper, is often by her side.

She loves the caw of the gulls, the thrum of the boat engines, the squeals of the line as lobstermen reel in their pots. She is not used to all these workers on the island, or to the drone of early morning construction. But she enjoys a slower life, awestruck tourists, and quiet nights. She knows she will be back to her routine soon — with a fresh coat of paint.