Frame the rough opening to 3 inches wider than the garage door size you have selected.
How to frame out a garage door.
The most expensive option is laying several courses of blocks on top of frost footings and then resting the edges of the slab on the blocks.
To make the door header the top of the door frame cut two 2x4s to the same length as the width of the original opening and nail them securely together.
Measure the distance from the bottom plate of the wall to a point that is 1 1 2 inches higher that the garage door height.
How to frame a garage doors opening in this case 9ft wide by 8ft tall.
Frame the rough opening to a height that is 1 5 taller than the door that you have selected.
But this is also the most durable and long lasting option.
Header requirement 2 at minimum the header should be 12 wide with doubled 2 4 at opening and ceiling running the width of the door with a 2 4 in the center of the opening for the center bracket to attach to.
Cut four 2 x 4 trimmers to this length and nail two each to either side of the rough opening.
You will need to add 1 2 of plywood between the 2x4 s to get the right wall thickness of 3 1 2.
How to measure the finished width and height use of 2x4s for the sides and header.
Frame the rough opening for the garage door to 3 inches wider than the garage door you have selected.
Find a 1 2 inch or whatever you decided for the bottom gap piece of scrap and place it under the door near the post.
How to frame a garage door 1.
Cut the door header.
Also make the rough opening 1 5 taller than the garage door leave a headroom of 14 or 12 minimum install the header jambs and center pad of the frame using a 2 x 6 lumber for the header jambs and center pad leave at least 5 of space on the sides of the door.
If you are installing a 9 wide door the opening will be 9 3 wide.
This is the actual thickness of a 2x4.