Interlocking Threshold Installation:
1. The type of threshold will depend on exposure of the door to the elements. If the outside surface of the door is protected by an overhang and is not hit by rain, any interlocking threshold can be used. If the door is exposed to any rain, a water bar (waterproof) threshold should be used. This type of threshold has a channel toward the inside to prevent water infiltration.
2. Using the end of the threshold as a guide, mark the height on each side of the door (hinge & lock sides). Determine the location of the interlocking lip of the threshold between the jambs. If a surface Ell is used, the lip of the threshold should be flush with the interior face of the door. If the concealed hook is used, the threshold lip should be placed 5/16 toward the outside. This dimension will vary depending on the threshold used. All water bar thresholds have a peak toward the inside which forms the water barrier or bar. This peak should be in line with the interior face of the door. Mark the lip location on the door jamb.
3. Remove the door and place outside face up. Add 1/8 to the marks for the height of the threshold. Draw a line across the door. Measure the distance from the door stop to the mark on the door jamb and add 1/32. This is the depth of cut. Cut the rabbet following the line. If the rabbet measures more than 3/8 deep, (detail) the bottom must be trimmed to clear the inside peak of the threshold.
4. Seal the cuts with primer or other sealer.
5. Fit the threshold between the jambs. This requires cutting around the stops or notching both ends of the threshold. Small notches or Vs must be made on the lower outside leg of the threshold to allow water drainage. (detail - 3 v for 3 foot threshold)
6. Cut the hook to the width of the door and nail in place in the rabbet spacing the nails no more than 1 apart along the outside edge. (detail)
7. Hang the door.
8. Place the threshold on the sill, close the door from the outside and push the threshold back into the hook. Mark the location and open the door. Remove the threshold. If the optional pan is used, fit it between the jambs with the bent side toward the inside. Run a bead calking along the inside edge of the sill. Place the threshold over the pan and calking. Close the door as above and check the fit. Make any adjustments if needed and check again. Open the door and fasten the threshold with the screws provided. Calk the ends of the threshold.
9. Hook can be adjusted (opened, pulled down, etc.) as needed.
Same as above except rabbet is on the opposite side of the door ( interlocking lip is toward the outside ) and there is no need for drainage holes.