Francis D. Lee, a Charleston architect and church member, was hired in 1852 to enlarge and remodel the building.
Inspired by architecture such as is seen in the Chapel of Henry VII at Westminster Abbey and St George's Chapel at Windsor Castle, Lee completed the project two years later in partnership with Edward C, Jones, a local architect with more experience then Lee.
Lee was only 26 years old at the time with only one statue on his resume, Jones was 28 years old but had been in construction since he was 15 years of age.
The project involved raising the entire roof of the building four feet, adding a Chancel, and constructing false flying buttresses to provide the proportions and looks of a Gothic building.
 In addition, the tower was raised and was built to include an office for the minister.
  The fan-vaulted ceiling, nave, and chancel closely resembled their English prototypes; the stained glass windows were considered among the finest in the country.
The church may have been the first building of Gothic architecture built in the United States.
The style is referred to as English Perpendicular Gothic Revival.

The large Chancel window was manufactured by the Henry E. Sharp glass works of Brooklyn, New York in 1854.
The two side windows in the Chancel are also by the same glass works and are mostly painted and etched glass.
The main window, created from painted glass, depicts both the old and new testaments, with Moses and Aaron flanking the Ark of the Covenant in the lower portion and the four Gospel writers arranged above them.
 
The Interior of the building was furnished with pews, pulpit, lectern, and communion rail, all carved from or capped with walnut.
 Gas lighting was also installed at this time.
 In recent times, a hand rail created by Philip Simons was added.
Francis D. Lee, a Charleston architect and church member, was hired in 1852 to enlarge and remodel the building. Inspired by architecture such as is seen in the Chapel of Henry VII at Westminster Abbey and St George's Chapel at Windsor Castle, Lee completed the project two years later in partnership with Edward C, Jones, a local architect with more experience then Lee. Lee was only 26 years old at the time with only one statue on his resume, Jones was 28 years old but had been in construction since he was 15 years of age. The project involved raising the entire roof of the building four feet, adding a Chancel, and constructing false flying buttresses to provide the proportions and looks of a Gothic building.  In addition, the tower was raised and was built to include an office for the minister.   The fan-vaulted ceiling, nave, and chancel closely resembled their English prototypes; the stained glass windows were considered among the finest in the country. The church may have been the first building of Gothic architecture built in the United States. The style is referred to as English Perpendicular Gothic Revival.
The large Chancel window was manufactured by the Henry E. Sharp glass works of Brooklyn, New York in 1854. The two side windows in the Chancel are also by the same glass works and are mostly painted and etched glass. The main window, created from painted glass, depicts both the old and new testaments, with Moses and Aaron flanking the Ark of the Covenant in the lower portion and the four Gospel writers arranged above them.  
The Interior of the building was furnished with pews, pulpit, lectern, and communion rail, all carved from or capped with walnut.  Gas lighting was also installed at this time.  In recent times, a hand rail created by Philip Simons was added.
Unitarian Church in Charleston