How to Join Baseboard to Wood Trim

Measure the distance between the edge of the wall and the wood trim of the door jamb. Use a measuring tape to get a good measurement. If the measurement is off, you will either have to cut the board again to trim away extra length or deal with unsightly gaps. Write the measurement down on a piece of paper.

Measure the baseboard and transfer the measurements from the wall to the top of the baseboard with a pencil. Indicate which side of the baseboard will butt directly against the wood trim of the door.

Place the baseboard flat on the table of the miter saw. Line up the baseboard so it is ready to be cut. On the side that will be directly against the wood trim of the doorway, cut the baseboard at a 90-degree angle. A simple flat cut will be all that is needed for this side of the baseboard because the baseboard will end directly at the wood trim. Make the cut for the other side of the baseboard by setting the miter saw at a 45-degree angle and cutting it in the appropriate direction for the corner you are working on.

Set the cut baseboard molding into place next to the wall. Check the baseboard to see if it fits in the area. Make adjustments if the baseboard is too short or long.

Nail the baseboard into place with a pneumatic nail gun. You can also use a hammer and finish nails and then set the nails below the surface of the baseboard with a nail set.

Fill the nail holes in the baseboard with wood putty. Allow the putty to dry and then paint or stain the baseboard to match the wood trim of the door jam. Once finished, the baseboard should look like it connects seamlessly with the wood trim.