Dominique de Menil wanted the pine floors darker, and darker still.

Steve McConathy remembers the day she selected the finish from samples in the lobby of the not-yet-opened Menil Collection in 1987. She chose a black stain so deep it would give just a hint of the wood's grain underneath. If you've eyeballed an all-black drawing by Richard Serra, Brice Marden or Sol LeWitt up close, you get the idea.

"Mizz D," as McConathy calls her, was devastated on the day the museum opened, when the first visitors in stiletto heels put pock marks in the soft pine — a 100-pound woman in high heels puts more pressure per square inch on a floor than a 6,000-pound elephant. The pock marks are still there, and many more have been added since.

McConathy, one of very few people left on the museum's staff who were hand-picked by the founder, has worked at the Menil since its planning stages in 1982. A native Houstonian who grew up on the city's southeast side, he started as the project manager for Melton Electric, the electrical contractor for the construction of the campus' first Renzo Piano building.

He loved it there from the start, although the Menil aesthetic took some getting used to. The museum was different than anything else being built in Houston, as the city filled with bland, rectangular office buildings fueled by that era's oil boom. Contractors couldn't get those atrocities done fast enough. But Mizz D and Piano wanted quality, even down to the details of the control room.

Tall and ruggedly handsome, with big blue eyes and a near zen-like calm, McConathy must have appealed to Mizz D as well. She hired him away from Melton: One day he was in charge of the electrical contracting. The next he was in charge of all the contractors. He stayed on as the manager of facilities, and he's never felt the need to leave.

For 30 years, McConathy has kept every inch of the museum and its more recent buildings looking good as new. But he has watched the Duraseal quick-penetrating stain of the floors suffer a slower kind of trauma than the one caused by high heels — damage that even soft tennis shoes cause. In the museum's lobby, foot traffic has worn the stain so thin that in places the only black that remains is deep in the pine's grain. Last year alone, more than 260,000 people visited the campus.

So now the inevitable looms: Next year, McConathy will oversee the refinishing of the floors.

To accomplish that task, and also install a new "digitally addressable" fire detection system, the Menil will close its main building to the public for eight months in 2018, beginning Feb. 26.

The staff will continue to operate as usual from the upstairs offices, but some gallery walls will have to be dismantled and the collections shifted through the building during the sanding and finishing process. The leveling mechanisms under the wooden air-conditioning grills in the floor are also being upgraded.

The campus' other exhibition buildings will operate as usual, open to the public 11 a.m.-7 p.m. Wednesdays-Sundays. That includes the new Menil Drawing Institute, which opens Oct. 7; the Cy Twombly Gallery, Richmond Hall and the Byzantine Fresco Chapel. (The Rothko Chapel, though launched by the de Menil family and adjacent to the Menil Collection campus, belongs to a separate nonprofit and will also continue as usual.)

Menil Collection director Rebecca Rabinow saw to it that funds for the repairs and upgrades to the main building were included in the $115 million capital campaign and master plan that were underway when she arrived last year. She and McConathy scheduled the project for next year so that public programs such as lectures and films won't suffer; they can be presented in the new drawing institute.

Rabinow has planned a "full-on" display of the permanent collections, including works that have never been shown, when the main museum reopens in the fall of 2018. "That's the fun part — the curators going deep," she said.

Standing in the lobby last week, McConathy looked up and down the museum's 400-foot long hallway. To keep the color consistent on that long stretch, the sanding must all be done at once.

McConathy still stays in touch with Piano's office and consults with them on changes. He's spent a good while making sure the floors will look exactly the same as they did 30 years ago. "Everything I do in the building has to consider his architecture," he said.

That's the Menil way. And his.