While building a new garage it is better to check available sizes make a selection and create a rough opening according to manufacturer specifications.
Garage door rough opening dimensions.
Most vertical track systems with torsion springs or other hardware require 3 3 4 in.
Standard sizes standard garage doors in our area are 8 9 16 and 18 wide.
Install the header on top of the trimmers and nail.
Typically one big door for two car garage will cost less comparing to installing separate smaller doors for.
For instance if your rough opening is 16 feet wide and 7 feet high then your best bet for a garage door is a 16x7 door.
Step 1 measure the old door if you are replacing an existing door with one of the same size or the new door of choice if you are building a new garage.
If you are installing a 9 wide door the opening will be 9 3 wide.
For instance if the width of the garage door is 8ft the rough opening should be 8ft 3 inches wide.
The span above the door opening is framed with a long header that supports the wall area above the door and this header will need to be raised or rebuilt in order to increase the overall door size.
1 2 or 1 in one direction of the other will won t typically cause you to have to shop for a non standard garage.
Take the measurements of both the width and the height of the inside of the opening.
This post is intended for purposes of clarifying how garage door sizes work and opening preparation.
If it s 9ft the opening must be 9ft 3 inches and so on.
If there isn t enough room above the opening this can t be done without raising the roof of the garage.
Nail or screw 2 x 6 jambs to the framing on the top first and then the sides of the rough opening.
It should be obvious that you don t use twice the thickness for the height since you will not be putting anything on the floor but you have been reminded just in case this thought escaped you at the moment.
Cut the header from 2 x 12 lumber and to a length of the rough opening plus 6 inches.
The size of the door will be approximately the same as this sometimes called the rough opening next measure the sideroom or space available on the left and right sides of the opening.
The width of the rough opening should be 3 inches greater than the width of the garage door you are purchasing.
The rough opening is equal to the size of the door but you need to figure back head and side room before choosing and installing the new garage door.
Width of rough opening.
The height of the rough opening would be the height of the garage door plus the thickness of whatever you are putting underneath the header in addition to the thickness of the mortar etc.
The rough opening is essentially the size of the finished garage door.
After installing the jambs your garage door opening should now be the same size as the garage door.
Frame the rough opening to 3 inches wider than the garage door size you have selected.
On each side although some systems can require up to 5 1 2 in.