Replace the threshold of an exterior door when it shows signs of rot or deterioration. Rotten wooden casings and the riser may need to be replaced as well.
Step 15: Set and fasten the new riser If you are replacing the old riser with a new one, set the new riser in place. Drive 8-penny galvanized finishing nails into the new riser, fastening it into place. Drive finishing nails into the new riser.
