However it is quite rare for anyone to want to do this.
Should openig be same size as garage door.
Much more often homeowners seek to increase the garage door size to match vehicles that don t easily fit through the existing opening.
For instance if the width of the garage door is 8ft the rough opening should be 8ft 3 inches wide.
Entry doors are usually 36 inches wide.
While a door width of 36 inches is oversized for an interior door it s the standard size for front doors the standard height remains the same however.
The width of the rough opening should be 3 inches greater than the width of the garage door you are purchasing.
This way the door will have a nice tight seal once the weatherseal or door stop molding is applied.
While technically the door could overlap the opening as much as the space will allow the design on the outside of the door disappearing behind the jamb will tend to distract from the overall outside appearance.
Doors that are 10 feet wide by 8 feet tall are single car garage doors.
Single garage door openers generally do fine with smaller openers while double doors may need a little more horsepower.
If it s 9ft the opening must be 9ft 3 inches and so on.
Doors larger than this are considered double car garage doors.
Measure the width and height of your garage door with a tape measure so you know what you have.
From a structural standpoint it is fairly easy to reduce the size of the opening in a garage thus creating the need for a smaller garage door.
The size of the finished opening should be the exact same size as the sectional garage door or down to 1 smaller on each side and or the top.