What depth plaster ring is required for 5/8" double drywall installation to ensure flushness?

For a 5/8" double drywall installation, the total thickness of the drywall is 1-1/4" because each layer of drywall is 5/8". To ensure that the plaster ring is flush with the finished surface of the drywall, it should match the combined thickness of the installed drywall.

A plaster ring that is 1-1/4" in depth will provide the necessary support and alignment, allowing the ring to sit evenly with the surface of the double-layered drywall. This alignment is crucial not only for aesthetics but also for proper installation of devices like switches and outlets, ensuring that they are securely mounted and functioning correctly.

Options that suggest a different depth, like 1", 2", and 3", will not provide the correct flush alignment with the surface of the double drywall installation and could lead to installation issues or a less polished final appearance.