For a rough opening, how much extra width is added for a 36" exterior door?

To determine the correct additional width for a rough opening when installing a 36" exterior door, it's essential to understand how rough openings are constructed to accommodate the door frame and allow for proper installation and adjustment.

The standard practice for creating a rough opening is to add extra width to the actual door size to account for the door frame, shimming, and clearance for any adjustments. For a 36" door, adding 1" to the width of the door allows for sufficient space. This extra inch gives room for the door frame (which typically has a thickness) and ensures that the door can swing freely without binding or rubbing against the frame.

Therefore, the correct answer reflects the industry standard, which adds 1" to the door width for the rough opening, turning the total from the door size of 36" to 37" for the rough opening. This practice helps ensure that the installation is straightforward and that the door operates smoothly.

The other options suggest either too little or too much additional space, which wouldn’t accommodate the necessary factors such as shimming and frame thickness, leading to potential installation issues.