How to Replace a Rotted Threshold Over Concrete
- 1). Remove the screws from the old threshold with a screw gun. Slide a pry bar underneath the threshold and gently lift up while working your way along the entire edge. Pull the old threshold out of the door opening once you have pried it up.
- 2). Measure the length of the old threshold with a tape measure. Measure and mark the length of the old threshold onto the replacement with a pencil.
- 3). Place the replacement threshold with the bottom side flat on the table of the miter saw. Slide the threshold over so that the outside edge of the blade lines up with the edge of the pencil mark. Pull the saw down in an even motion while squeezing the trigger to cut the threshold to length.
- 4). Slide the replacement threshold into place in the door opening between the side door jambs. Drill through the threshold into the concrete with a masonry bit approximately every 8 to 10 inches. Drill to a depth in the concrete that matches the length of the anchors.
- 5). Remove the threshold and slide the plastic anchors into the holes in the concrete. Apply a bead of window and door caulk along the base of the door opening between the side jambs using a caulk gun. Slide the replacement threshold back into place.
- 6). Drive masonry screws through the holes in the threshold into the anchors in the concrete until the screws are slightly below the surface of the threshold.
Source...