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SC’s first below-sea-level parking developed for upcoming East Bay hotel

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The 30 new parking spaces under The Saint Hotel on East Bay Street can be considered historic even though they're still being built.

That's because they're an architectural first: the most tightly packed, below-sea-level parking ever constructed here — or in the state of South Carolina, for that matter.

This tiny garage may even be the most expensive parking spaces built between New York and Miami, though no one definitely tracks this sort of thing.

The extraordinary effort to create them derived from a simple fact: Developer Mark Wyant concluded they were necessary to get city approval to construct his new 45-room hotel on the historic site. No parking, no hotel.

"I couldn't make the building any higher because of height limits," he said. "The only place we could take it was down."

Mark Wyant .jpg

Mark Wyant. Grace Beahm Alford/Staff

The exceptional cost, more than $75,000 per space, stems from two unique factors: A highly ambitious construction project to build a waterproof basement several feet below the peninsula's water table, as well as the state's first specialized mechanical stacking system capable of shuffling 27 cars around a tight space with only a few inches of clearance.

In other words, this isn't your routine city garage.

"This is on a whole other level. It's parking in a bathtub," said Jacob Lindsey, Charleston's planning director. "It is very elaborate and very costly."

Building that bathtub

The greatest challenge was constructing a suitable space below sea level, in soft, debris-filled sand just a few feet away from two narrow city streets and within a stone's throw of several delicate 19th-century buildings.

That job fell to William Snow and his son, William Snow, Jr., a professional engineer. Their Palmetto Gunite Construction Co. is used to difficult projects. For example, it bolstered the foundation of the Morris Island Lighthouse, which sits in the Atlantic Ocean.

“This was probably the most challenging underground site we’ve ever seen, and we’ve done a lot of work in Charleston for a long time,” Snow said. “We don’t have basements in Charleston for a reason. This hotel has a 10-foot basement in it.”

Conventional pilings were out of the question: The vibrations from their installation would damage nearby buildings. Simply excavating the site and drawing down the water table would cause nearby streets to collapse.

Their solution was to construct a secant pile with more than 270 interlocking micropiles, a technology developed in Italy after World War II to create foundations near delicate historic buildings. They also can be sunk within a foot of an existing building. "There's no vibration at all, and that's the big deal," Snow said.

A machine drilled into the sand and muck, through the groundwater, shooting out grout to make a concrete column with a steel center (the drill bit).

The company modified these drill bits because of all the debris on the property: This site is right on Charleston's historic walled city, a portion of which was uncovered not far from the parking basement.

"It was kind of a mess," Snow Sr. said of the site, which included several feet of palmetto logs, large ballast stones and assorted bricks from foundations of buildings long gone.

The piles not only had to create the garage volume, but since the site was so tight, they also had to form part of the hotel's foundation. About 242 micropiles went 30 feet down, far enough to reach a clay layer. About 32 others went 80 feet down into the marl to provide structural support for the building on top.

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Parking stack lot.jpg

Mark Wyant, owner of The Saint Hotel, details the state-of-the-art parking-stack system now under construction on East Bay Street Wednesday, Oct. 9, 2019, in Charleston. Grace Beahm Alford/Staff

Once the micropiles were in place, the pit was dug out and its rough-looking walls were reinforced with 8 inches of smoothed shotcrete. A heavy floor, tied into three 70-foot-long micropiles, was built with a few feet of rock and concrete to keep the tidally-influenced groundwater from pushing it upward.

Today, it looks like any other basement, but Snow knows better. He and his son recently presented the project to a conference of geotechnical engineers in Australia.

"When they dug the hole — my wife thinks I'm crazy — I got all excited because it wasn't leaking," he said. "Probably five people in the world realized what we were doing, but I was pretty fired up about it."

"Our best work is never seen."   

Filling that bathtub

The idea of using fancy machines to stack and store cars was conceived more than a century ago, but it's only been in recent decades that rising urban real estate prices, zoning codes and technology have converged to make them a viable business.

Max Wassef is president of Parkmatic Car Parking Systems, one of a few companies specializing in the contraptions.

Wyant said he turned to Parkmatic because of its expertise, but also because it uses South Korean manufacturing and Egyptian steel — sources that he felt were more immune from the ongoing trade war with China.

He ordered a semiautomated system that will park 27 cars three deep, three wide and three tall in a space about 25 feet wide, 60 feet deep and 21 feet tall. A smaller stacking system nearby will handle another three, for 30 total spaces.

Guests arriving by car will enter an open aisle in the middle of the hotel, a private passage between Cumberland and Faber streets. The valet will drive the vehicle onto a pad, then use either a keyfob or a special app to activate the machine. It might take as long as 90 seconds or so for the machine to shuffle a car from entry pad to a rear space.

The hotel will have an emergency generator, just in case, and Wyant said the machine also could even be operated very slowly by a hand crank, if it came to that. Retrieving a car by hand might take 20 minutes.

"It will shift cars like a Rubix cube," Wyant said. "The cars will be very close. You can't get out of the car."

The vehicles will snuggle up within inches, and because of the tightness of the site, the hotel's sewer lines also will weave through the garage space.

Other recent Charleston buildings have underground garages. Some have lifts and even dewatering systems, but nothing quite as tight as this. It's likely a sign of things to come, however.

The Saint isn't Wassef's only Charleston client. Parkmatic also is providing three carousel parking structures to a small new apartment project soon to be built at 84 Line St. Each carousel will be able to store about 10 cars in the same space as two conventional parking spaces.

"We’re really excited about Charleston right now," Wassef said.

The Saint's valet parking spaces won't necessarily be the most expensive to park in, though at about $35-$38 a night, plus tip, they'll rank up there.

But given approximate cost of $75,000 per space, aside from land costs, they certainly set some sort of state record — at least for now.

"I didn't have any idea of what I was getting into until I got into it," Wyant said. "I built enough three-story Hampton Inns years ago. That got kind of boring."

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Reach Robert Behre at 843-937-5771. Follow him on Twitter @RobertFBehre.

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