How to Size a Rough Opening Bifold Door

Bifold doors are a modern convenience. Riding on tracks from above, they span large openings, providing unobstructed access to the contents of the closet. Rough openings for bifold doors should allow enough space for hardware, drywall and jambs.

The Most Common

The majority of bifold doors are 80 inches tall. The width varies depending on available space, but openings typically graduate in 24-inch increments up to 72 inches or more.

Divided Panels

Individual panels are divided equally. For example: A 48-inch, or 4-O -- pronounced "four-oh," -- bifold typically consists of four 12-inch-wide panels.

Jambs or Drywall

The typical bifold door is finished with drywall only. But there's no reason why you can't add jambs if desired. If jambs are planned, the rough opening will be larger than a drywall-only opening, to allow for the jambs.

Drywall Opening

The required size of the finished opening for a 48-by-80-inch door is 48 by 82 inches. The rough opening should be 49 by 82 for a 48-by-80-inch door. This allows for 1/2-inch-thick drywall on both sides and at the top, 80 inches for the doors and hardware, and a 1-to- 1 1/2-inch space under the door. The space between the floor and the bottom of the door may vary depending on the type of flooring.

Opening With Jambs

The rough opening for a bifold with jambs is framed slightly wider, to allow additional space for a door jamb on three sides. The difference in height is insignificant, since it adds only 1/4 inch. Door jambs are 3/4 inch thick, for a total of 1 1/2 inches, including 1/4 inch of space around the perimeter for shimming. The rough opening for a 48-by-80-inch door with jambs would be 50-by-82 inches.

From Scratch

Drywall Opening

Figure the rough opening size by adding 2 inches to the height of the bifold, and 1 inch to the width.

Jamb Opening

Figure the rough opening size by adding 2 inches to the height, and 2 inches to the width.

One Size Fits Both

If you're not sure if you're installing drywall or jambs, it's fine to opt for the bigger jamb opening. The difference in size is not that big a deal, and it allows you the option to trim it out later with jambs or lumber of any type.