The ceilings in the original house had an interesting cove detail that the homeowners wanted to duplicate in their new addition.
To provide a solid attachment point for the prefabricated arches, the author installed rows of blocking between the wall and ceiling framing. The blocking is centered 12 inches from the wall/ceiling intersection, and also provides good backing for drywall.
To bring the 5/8-inch ceiling drywall, 1/2-inch wall drywall, and 1/4-inch flexible drywall that would be used to form the cove into the same plane, 1/4-inch plywood furring strips needed to be attached to the blocking.
The arches were fastened to the furring strips 16 inches on-center. A narrow crown stapler and dabs of construction adhesive were used to make the attachment.
Workers sprayed both sides of each panel with a mister. Allowing the wet panels to sit for a few minutes before installation increased their flexibility even more, making it easier to form the flexible drywall to the 12-inch radius of the cove.
When forming the panels, crewmembers worked slowly and avoided pushing hard on the center of the panel, which would break the paper face and buckle the drywall.
Once the panels conformed to the cove, they were screwed in place with regular drywall fasteners on 5-inch centers.