- 1). Inspect the existing trim to determine which sections are damaged and must be replaced. Measure and record the length of each piece of trim that will be replaced. Add 6 to 12 inches to your total to give yourself some margin for error when cutting the trim. Use this figure when purchasing the material for your replacement trim.
- 2). Place a block of wood next to the piece of trim you will be removing. Pry off the trim using the block as a leverage point for your pry bar.
- 3). Use a miter saw to cut sections of new trim to match the measurements of the damaged trim that was removed in the previous step. Cut the ends of the trim at a 45-degree angle if you are joining two pieces to form a square corner.
- 4). Attach the replacement trim to the home with finishing nails. Use a nail set and hammer to sink the head of the nail below the trim's surface. Fill in the gaps over the nail heads with wood putty. Remove any excess putty with a putty knife and let it dry. Use fine grain sandpaper to blend the putty in with the rest of the trim.
- 5). Apply the finish of your choice to the trim to protect it from the elements. You can also purchase pre-finished trim and skip this step. Allow the finish to dry overnight. Apply a bead of caulk around the edge of the trim to seal any gaps between the trim and the wall. Wet your finger and use it to smooth out the caulk.
Source...