Final answer:
The minimum unobstructed head room above the roughed frame access opening for the attic is 30 inches, which is a standard in residential construction for safe attic access.
Step-by-step explanation:
The minimum unobstructed head room above the roughed frame access opening for the attic is 30 inches. This standard ensures that individuals have enough space to safely access the attic without the risk of head injury. Although building codes can vary by region, 30 inches is typically the minimum requirement that must be met for residential construction to provide adequate head room for attic access.