If the blueprint does not specify the rough opening for an exterior door, what is the standard practice for framing the width?

Framing an exterior door rough opening 2 inches oversize is standard practice because it allows for proper installation and adjustments. The additional space accommodates the door frame and provides room for shimming, which is crucial to ensure the door is plumb and level once installed. This oversizing compensates for variations in wall thickness, door frame dimensions, and any potential alignment issues that might arise during the installation process.

When framing a door opening, the expected width typically includes the width of the door slab and the thickness of the jambs on both sides. Therefore, adding a bit of excess space (2 inches total) facilitates easier handling, installation, and ensures that seals around the door are effective, ultimately contributing to energy efficiency and security.

Other framing measurements may not allow sufficient space for these considerations, which can lead to difficulties during installation or result in an improperly fitted door that may not function correctly over time.