When Vanity Fair publisher Chris Mitchell and Condé Nast Traveler editor-in-chief Pilar Guzmán bought their dream getaway at 62 Dunemere Lane in East Hampton in 2013, they had no idea what they were getting into.

“We love old houses. But there wasn’t a right angle in the entire house. Every floor and doorway sloped. It didn’t have a foundation,” Mitchell says of the 1890s-built labor of love. The couple eventually added a foundation and carefully restored every aspect of the home, while also incorporating elements of modern Danish design. The work took nearly three years and expenditures “into the seven figures.” Still, Mitchell says it was worth saving a piece of Hamptons history from the wrecking ball.

“The only other bidder on the house [when we bought it] was a developer who was going to knock it down,” he says. Now, after their detailed overhaul — which saved all of the original doors and windows but added contemporary fixtures, bathrooms and closets — there is no chance of the home being razed, and they’ve decided to sell for $12.5 million.

In Sag Harbor, in an enclave of historic village homes, another buyer spotted a diamond in the rough in need of preservation. The interior-designer owner of 39 Suffolk St., a sailor’s home from the 1830s, poured generous amounts of cash into the property — saving every scrap of period detail possible, according to listing broker Rylan Jacka of Sotheby’s International Realty. The four-bedroom, four-bathroom house, with its original support beams, windows, wide-plank floors and a modern kitchen, is now on the market asking $4.9 million. A slice of history in the making.