Monumental Church is an octagonally planned masonry structure with both the floors and roof framed in wood. The church was designed by Robert Mills and built in 1814 and is a meld of Roman, Greek and Egyptian motifs. The portico of the building features six Doric columns, and in its center, the tomb combines a sarcophagic base with a Roman-inspired urn.
Structurally, the work features an early use of slender cast iron columns, which support the balcony in the main sanctuary space; an innovative use of a shallow laminated wood dome, with central raised lantern, based on the principles of French architect/engineer Philibert De L’Orme; and an intricate assembly of wood elements to create the spiral staircases up to the balcony level. Silman performed a structural analysis of the building, and also developed repair designs of the existing historic systems in order to strengthen the termite-damaged sanctuary floor.