A concrete mixing truck boarded a barge last week for restoration work on the historic Matheson home in Islamorada.

The home adorns the 3-acre clearing at Lignumvitae Key Botanical State Park, an island off Indian Key Fill that’s accessible only by boat or kayak. The home serves as the park’s visitor center.

The volumetric mobile mixer, which weighs about the same as a humpback whale, navigated a narrow concrete and steel gangway to board the barge.

“It was definitely something different than just driving up and down the highway delivering concrete all day,” said Brian Conover, a spokesman for All Keys Concrete of Key Largo. “It was a unique experience.”

“[The Florida Department of Environmental Protection] is actively working on multiple restoration projects at Lignumvitae Key Botanical State Park,” DEP deputy press secretary Alexandra Kuchta said. “The first project is at the historic Matheson house, which was built in 1919. It is currently in the process of having its foundation repaired.”

The park’s main visitor landing is also undergoing structural repairs at its outermost “T” dock.

The projects began in April and are expected to be completed by late fall or early winter, according to Kuchta.

“Both are currently on schedule. We look forward to welcoming guests back to the park as soon as possible to enjoy these enhanced amenities,” she said.

The Matheson house is considered the showpiece for the offshore island. It was built as an island retreat by wealthy Miami chemist William J. Matheson, who specialized in commercial dyes.

The 5-acre cultural site includes not only the house, but a cistern, hurricane shelter and other amenities. It once featured landscaping by famed botanist David Fairchild. Today, Lignumvitae Key Botanical State Park is known for its preservation of lush subtropical growth.

“The virgin tropical hardwood hammock that thrives on this island was once common on most of Florida’s Upper Keys,” the Florida State Parks website says. “Most of these forests have been lost to development on other islands.”

Lignumvitae Key’s hardwood hammock supports 65 species of rare native trees and shrubs.

The contractor that was awarded the restoration contract from DEP is Shoreline Foundation, a Pembroke Pines company specializing in marine, heavy highway and deep foundation construction. Shoreline, in turn, subcontracted local companies for materials and work needed, including All Keys Concrete, R. Hendrick Construction and Pumping the Keys.

R. Hendrick Construction of Islamorada is repairing the spalling concrete on the historic house.

“What a project getting our workforce out to an island daily!” said R. Hendrick Construction office manager Paula Jo Vieceli. “Spalling repair is not the interesting part of this story, of course, but it’s the history and the local flavor. It is with a big thank you to Shoreline that we can say the restoration of the historic house has been completed by three Keys-based, family-owned and -operated small businesses.”

Conover is appreciative of Shoreline’s professionalism and expertise.

“It worked out perfectly. Shoreline knows what they’re doing,” he said.

Pump the Keys of Tavernier was used to pump concrete and supply 450 feet of hoses.

“Moving forward, we will wait for the concrete to cure, then go back to strip the forms and stucco texture the building as needed to match original finish and paint,” Vieceli said. “Again, not impossible but very nerve racking,”

Lignumvitae Key Botanical State Park will remain closed to the public until the repairs are complete.