The front edge of a box installed in a combustible wall must be flush with the finished surface. What is the proper term for this alignment?

• A. Flush
• B. Recessed 1/8 in
• C. Protruding 1/8 in
• D. Set back 1/4 in

Answer: (A)

Flush means the front edge sits exactly in line with the finished wall surface. That exact alignment is why it’s the correct term here: the box is neither recessed back from the wall nor protruding beyond it, but aligned with the face of the wall. This ensures a clean, even finish for trim and wall coverings, and it helps maintain proper clearance and firestop conditions in a combustible wall. If the edge were recessed, it would sit back from the surface, leaving a gap for the cover plate to sit away from the wall. If it protruded, it would stick out past the finished surface, creating a snag hazard and a poor finish. A set back by a specific amount is a form of recessed placement, not flush.