RICHMOND — Mr. Jefferson’s Capitol has a leak, but don’t lay the problem at his feet, even if the puddles form precisely there.

Sometimes when it rains hard in Richmond, water trickles into the Capitol through a leaky skylight high above a statue of the former president and Virginia governor.

The rain winds up on the floor — not in flood quantities, but enough to require mop-ups around the bronze likeness of the guy who designed the place.

“Call it the ghost of Sally Hemings if you want to,” said Bob Brink, a former state delegate who serves on the Capitol Square Preservation Council. “Seriously, they’ve had problems with that skylight since it was built.”

The original part of the Capitol that Jefferson designed in 1785 manages to keep the elements at bay, thanks in part to two major renovations that took place a century apart. But there’s a stubborn leak in the underground addition tacked on 222 years later.

The source is the skylight, part of a $104.5 million makeover completed with great fanfare in 2007. The historic structure was not only renovated but expanded with a 27,000-square-foot addition. The new part was built underground, an architectural and engineering feat that created space for meeting rooms, a visitors center and a cafe without messing with the exterior sight lines of Jefferson’s “Temple on the Hill.”

One small feature of that great undertaking was the skylight, which allows natural light to filter down into the addition tucked under the Capitol’s south lawn. The sunlight shines into an atrium between the cafe and a curving staircase leading up to the historic part of the building where the House of Delegates and Senate meet.

Smack in the middle of the atrium stands the bronze likeness of Jefferson, billed on his pedestal as “architect of liberty.” He holds drawings for the columned Capitol, which was inspired by the Maison Carree, a 1st-century Roman temple in Nimes, France.

The skylight was “a wonderful idea architecturally because it makes this less like a cave,” Brink said. “There was no other way to let natural light into this space.”

Yet as many a homeowner knows, skylights can leak. This one is a particular challenge because it was installed not on a rooftop, but in the ground, in the middle of a stone plaza where tourists have been free to walk and even roll across it on Segway tours of Capitol Square.

The skylight sits just off the Capitol’s south portico where, every four years, a new governor is sworn in. Glass blocks form a circle around the state seal, made out of metal. Every couple of years, the state applies a sealant around the glass blocks and caulks around the surrounding stonework. The fixes work for a while. Until they don’t. Then out come the mops until the whole thing can be sealed and caulked all over again.

Workers sealed and caulked again last month. This time they also replaced some glass blocks that had cracked and did some caulking on the nearby Capitol steps as well.

But the state is looking for a more permanent fix now. Last week, the Department of General Services asked engineers to investigate whether there’s a more lasting repair. If not, the state will consider getting rid of the skylight, department spokeswoman Dena Potter said.

“Okay, tell us what will fix this permanently,” Potter said of what the engineers were told. “We’ve had the whole water penetration issue for years.”

Potter expects the department to have a plan by early 2021, so any repair or replacement can be completed before the next governor is inaugurated in January 2022.

While the engineers look into the matter, the state has decided to fence off the skylight to halt foot and Segway traffic.

It’s not clear why the leak has been so tricky to fix, though there’s general agreement that the skylight was an ambitious feature in an already complicated project.

“Architects have great ideas,” Del. Mark D. Sickles (D-Fairfax) said wryly as he ate lunch in the cafe.

“It’s a very sophisticated ceiling, so you’re bound to have problems with constructability,” Sickles said. “The engineers — speaking as a person who works for a construction company — the engineers oftentimes say, ‘You can build this,’ but they don’t build it. They have to give it to a construction company to build. So I would be very hesitant to throw blame around.”

George C. Skarmeas, who led the 2007 expansion and is one of the nation’s leading historic preservation architects, said he could not comment on the issue.

“I have not been on site for several years now and I am not in a position to make any statements remotely without having the benefit of an on-site visit and assessment and a full understanding of what the issues are, where, etc.; nor what the corrective action is that the State implements to address the issue and what it performs and why,” the Philadelphia-based Skarmeas wrote in an email.

Brink thinks the problem is a combination of factors, including the presence of the heavy state seal at the center of the blocks.

“I’m certain there are all kinds of physics things that come into play,” he said. “You have that metal piece there that absorbs the sun. I imagine you have expansion and contraction.”

He stopped to note that he’s not an engineer, just an interested, longtime observer.

“I’m on my second decade speculating about the skylight,” Brink said