Step 1 remove old trim.
How to cut garage door trim.
Learn how to install our vinyl thermostop garage door trim.
Cut a piece of trim to that measurement.
Cut the first miter on the head moulding piece.
Step 2 cut your trim to size.
Measure the inside dimensions of the garage door jamb horizontally across the top and vertically along both sides.
Measure for the brick molding the trim that will face the street starting with the top piece.
Measure across the top of trim on the outside of the door from the outside corners of both pieces of vertical trim that you just nailed on.
How to trim a garage door opening 1.
Nail the head moulding piece to the door jamb with trim nails.
Make a mark before you cut another 45 degree miter with the power miter.
How to install trim around a garage door opening.
If you currently have trim around your garage door you will need to remove it before installing the new trim.
Then measure the length of the moulding from the inside point of the miter you just cut to the desired length.