How to Trim Around Beams

Use a measuring tape to determine the length of each wall section, moving up to the beam, around its sides, and back to the wall again. Write down each measurement after checking them at least twice.

Take an adjustable miter saw and cut sufficient wood trim pieces to match your measurements. Cut the pieces at a 45-degree angle, with the slope on the sides that face into a corner. Do the same for the sides of the pieces that cover a protruding corner, but cut the 45-degree angle in the opposite direction, sloping inward. Use a miter saw with different angle measurements if the beam corners are different than a standard 90-degree turn.

Place the cut pieces against the wall and fit them together around the beam before installing, to check the fit. Cut a new piece with the miter saw if the current piece does not fit correctly in the dry run.

Install a tube of adhesive for wood projects, such as Liquid Nails, into a tube spreader gun and squeeze the adhesive onto the back of the first trim piece. Place the trim piece on the wall and press it into place. Do the same as you work the remaining trim parts around the beam. Go back and drill a small hole in each piece for one or two finishing nails.

Place a finishing nail on the hold and hammer it into the wall. Use a nail punch to hammer the final blows without damaging the trim part.

Take the adhesive out of the spreader gun and replace it with a tube of white caulk. Seal up each part or gap in the trim pieces so the finished trim has no breaks. Make sure to seal the top of the trim as well where it joins with the wall and beam.

Let the caulk and adhesive dry. Paint the finished trim with a paintbrush and your choice of paint. Let the trim dry for a day.