A rare gut-renovated turn-of-the-century townhouse on tony East 64th Street has found a buyer within three weeks — and it’s an all-cash deal, Gimme Shelter has learned. 

The limestone residence at 165 E. 64th St., between Lexington and Third avenues, was asking $18.5 million. The buyer is an international financier who has agreed to pay close to the home’s asking price, a source said. 

The signed contract was first noted in Monday’s Olshan Market Luxury Report.

The seller, developer Titanium Property Group, bought the property for $6.5 million in 2024 and completely gutted it — including the facade, which transformed from a brownstone into a limestone townhouse. 

It turns out that the wrong side of the tracks on the Upper East Side may becoming the right side: If the house had been a block west, the renovation would not have been possible.

That’s because East 64th Street, from Fifth to Third avenues, is part of the Upper East Side Historic District.

It’s impossible to touch the facade of landmarked homes. But there are no such restrictions for similar homes east of Lexington, said the home’s listing broker, townhouse expert Charlie Attias, of Compass.

And these days, he added, Manhattan townhomes are more popular than ever.  

“Since COVID, there has been a drastic increase in townhouse demand. Everyone wants home offices because whole families — husbands, wives and kids, whether they are adult children or still students — are all working from home. People want more space and privacy,” Attias said, adding that it was no surprise the townhouse was snapped up within three weeks. 

And while the house was not built on the site of a teardown, it was essentially “brand new — from the foundation to the plumbing, electricity and windows, plus a new floor was added,” Attias said. 

“People don’t want old townhouses. We knew we had a winner. There was a lot of demand for the product,” he added. 

The 20-foot-wide limestone residence now has an elevator and an additional fifth floor with a roof deck, along with a home gym and a pet spa. 

At 7,000 square feet — with an additional 1,900 square feet of outdoor space — the glam residence comes with modern interiors, and features six bedrooms, six baths and two powder rooms. 

Design details include 10-foot-high ceilings, wide-plank white oak floors, solid white oak staircases, custom crown moldings, cove lighting and radiant floors indoors and out.

There’s also a finished basement and a roof deck with a summer kitchen. 

The home opens to a foyer that leads to a chef’s kitchen with 50 feet of custom cabinetry, a built-in coffee system, wine storage, and two sinks and dishwashers. Oversized window walls open to a landscaped garden with a snow-melting system and speakers. 

A grand parlor floor overlooking the garden through oversized windows is next, for more formal entertaining. This floor boasts a formal living room, a dining room and a wet bar with a wine fridge.

The next floor hosts a primary bedroom suite with a fireplace, a private terrace with a snow-melting system and a spa-like bath. An additional flex room on this floor can function as a home office, a gym, a dressing room or an additional bedroom.

Additional bedrooms are on the next two floors.

Finally, the rooftop features a summer kitchen and views of the neighboring townhouse gardens, while an excavated cellar level boasts stone floors, a pet spa-slash-dog wash station and a laundry room.