The Old Exchange & Provost Dungeon, also known as the Custom House, and The Exchange, is an historic building at East Bay and Broad Streets in Charleston, SC. Built in 1767-71, it has served a variety of civic institutional functions, including notably as a prisoner of war facility operated by British forces during the American Revolutionary War. The building was designated a National Historic Landmark in 1973. It is now a museum operated by the Daughters of the American Revolution.
The lime plaster had been restored in 2007 and finished with a lime wash, that was again refurbished in 2011. The frequent need to repaint was a problem for the museum as they are completely reliant on visitor fees and attendance drops whenever the building is scaffolded. A mineral silicate finish was selected to deliver an appearance akin to lime wash, but with durability to last decades. The previous lime wash color had also faded/changed to a yellow ocher color, that is was not historic so a non-fading solution was required.