One of downtown Charleston's smallest hotels is more than doubling in size.

The Restoration on King, a 16-suite luxury hotel at 75 Wentworth St., recently started construction on a project to expand into the adjacent building at 77 Wentworth and a new seven-story hotel to be built at 79 Wentworth.

The project is expected to cost more than $15 million, according to J.R. Anderson of Jeffrey R. Anderson Real Estate Inc., the Cincinnati-based firm that owns the hotel properties.

With the added space, the hotel will tack on 34 more rooms, a larger lobby and a two-level rooftop space with a swimming pool and an outdoor restaurant and bar.

It's expected to be completed by July 2014, Anderson said.

"We run an occupancy rate in the high 90 percent range, and many weeks we get more phone calls for reservations than we can satisfy," Anderson said. "We want to expand to further satisfy customers so they can all enjoy what we call the 'ROK' experience."

Anderson Real Estate acquired the Restoration on King boutique hotel in 2012 for $6 million, according to property records. Several months later, it bought 79 Wentworth to begin the hotel expansion.

The scope of the project grew this year when the company bought 77 Wentworth, a building that includes several condominiums and the former Yo Burrito restaurant on the first floor, for $3.5 million in a foreclosure auction in February.

Anderson Real Estate owns all of the condo units except for one, which is privately owned, according to the deed. Anderson said one two-bedroom condo will be used as a hotel suite.

The former Yo Burrito will be converted into the new lobby with a wine and coffee lounge, according to general manager Howard Letts. The former restaurant's outdoor patio will be redesigned with new landscaping and will reopen by the end of the summer, he added.

The meat of the project is at 79 Wentworth, where the new seven-story structure will rise. It will house six stories of rooms and the new main entrance and check-in desk, Letts said. The current check-in lobby will be converted into a boardroom.

"Its' going to be a very interesting small boutique hotel, and I think it will be a nice addition to the Charleston hotel market," Letts said.

Reach Abigail Darlington at 937-5906 and follow her on Twitter @A_Big_Gail