One of the most important parts of framing walls is getting the rough openings right. Items that determine what the height of One of the most important parts of framing walls is getting the rough openings right. Items that determine what the height of your opening will be are floor finishes and the use of underlayment. Door widths will stay constant with the size of a standard door.

In new construction most doors are hung after the floors are installed. This allows flooring contractors (tile, hardwood, vinyl, laminate) to lay their flooring products without making tricky cuts around door jambs. It also makes for a neat and clean door installation. Exceptions to this are carpeted floors. Doors are hung before the carpeting is laid. When doors are hung in carpeted areas, its a good idea to shim them up 1/2", putting a shim under each jamb leg. This eliminates the need to cut the doors down after the carpet is installed.

For a 6' 8" high door (80 inches) I like to frame my rough opening height at 82 3/4". This allows room for all the situations mentioned above. If your header material is a double 2x12, holding it to the top plate will give you that height.

Rough openings for door widths are pretty much standard. The rough opening width is 2 inches wider than the door itself. this allows room for the door jambs which are usually 3/4" thick. This gives you approximately 1/2" of play and shim room when installing a prehung door. For a 36" door (3' 0") the rough opening width would be 38". Here are the most common door sizes and their rough openings.

Door Size Rough Opening Size

2' 0" x 6'8" -26" x 82 3/4"
2' 2" x 6'8" -28" x 82 3/4"
2' 4" x 6'8" -30" x 82 3/4"
2' 6" x 6'8" -32" x 82 3/4"
2' 8" x 6'8" -34" x 82 3/4"
2' 10"x 6'8" -36" x 82 3/4"
3' 0" x 6'8" -38" x 82 3/4"

To figure the rough opening for double doors or french doors, take the door size times 2 and add 2". The most common sizes for exterior doors are the 2'8" and the 3'0" doors. The 2'8" is usually used for the back door and the access door from the garage. That size door for exterior use is being used less these days because of the size of appliances and furniture. Exterior doors with sidelights and sliding patio doors rough openings vary from manufacturer to manufacturer. These should be verified and gotten from the supplier.

Getting the rough openings right the first time keeps the sawzall in its carrying case and having to change the opening after the walls are drywalled and painted.

Mike Merisko (c) 2006

www.sawkerfs.com