Over the last few years I have been an Owner Project Manager for many construction projects that require wood trim to be installed and I am amazed at the number of people that call themselves carpenters that do not know how to install wood trim rapidly and concisely, so I am going to talk about trimming out doors in a large project and how time can be saved using a method that I was taught by my Father and a few other Craftsmen that I worked with.

After the pre-hung units are in place the first thing that you do is measure the header of the door on the inside of the frame then add one half inch to it that will give you the size of the casing from heal cut to heal cut when you are going to miter the casings. The heal cut is the short point of the miter. If the door is 36 inches wide inside of frame to inside of frame then the casing from heal cut to heal cut will be 36 and one half inches long.

On each leg of the casings you measure from inside of frame at the top to the floor then add 1 inch to the measurement from heal cut to floor. One item that you need to check on the frames is the inside and outside of the door frames to make sure they are same measurement.

Once you have all the measurements of the doors then you can go to the miter saw and set up to start cutting all the stock you need for trimming out the doors. The first thing you should check is to make sure the saw is cutting a forty five degree angle. Cut a piece if stock and check to make sure the angle is true.

Set up to cut one side of the miters of the top casing for the number of pieces of stock to do the job also cutting the corresponding side of the casing leg you need at one inch longer. The next step is to set a stop to cut the other miter of the top casing checking to make sure the saw is cutting true again before you start the last cut on the top casing also cut the corresponding leg at this time also.

After you have all the materials that you need cut for the door trim go to the first door and at the header you put a quarter of an inch mark up on the jamb for the reveal of the top casing. Then on the side jambs you put a quarter of an inch mark at the top crossing the first mark you have and then a few more on each side for the casing legs on both sides.

Install the header casing first on the marks with the heal of the casing lining up on the cross hairs on each side at the top. Tack that in place then take the casing for each leg and turn them over putting the miter on the bottom and marking the casing on the top of the top trim. Using a square and a hand saw you cut the mark off square. Glue the joint at the miters and nail in place along with the casing legs.

This is done on each door jamb it should take no more than a half hour to case out a door both sides. Installing the top casing and both legs on both sides of the door.