How are the graceful lines on a vaulted ceiling made? The recipe requires a few essential items, used by generations of plaster workers, including those who are currently renovating the Harvard Art Museums:

two steel braces

expanded metal lath

scratch coat

stucco

Cross two curved braces and join them with galvanized steel tie wire, creating a vaulted frame. Take the metal lath sheet (metal that has been pierced and pulled apart so that plaster can key into the holes) and fix it to the braces. Cover the metal lath with the scratch coat mixture. Apply stucco on top of the scratch coat for your desired effect.

When the Fogg Museum opened in 1927, the arcades that wrapped around the Calderwood Courtyard featured walls and vaulted ceilings that were covered with stucco, a technique that creates a rough, textured finish. Great care has been taken to restore the original appearance of these arcades so that when you visit the Harvard Art Museums in the fall of 2014, the arcades’ ceilings and walls will appear as they did more than 80 years ago.

Here are some recent photos of this impressive process.