In this video. This Old House landscape contractor Roger Cook fixes a sagging fence gate and also replaces a missing picket.
1. Unscrew the gates from the fence posts and remove the old hinges.
2. Set the gate across two sawhorses.
3. Steal a picket from an inconspicuous area of the fence and use it to replace broken gate picket.
4. Hold the hinges against the 2x4 gate rail and drill 3/16-inch-diameter pilot holes for lag screws.
5. Fasten the hinge to the gate rail with lag screws. Repeat to install hinges on the second gate.
6. Remove the broken picket from the gate and attach a replacement picket using 1 5/8-inch deck screws.
7. Stand the gate in the fence opening and on top of a 2x4; slip a wedge underneath the gate to raise it to the proper height.
8. Leave a ½-inch space between the gate and fence post.
9. Drill pilot holes into the fence post.
10. Fasten the hinge to the fence post with lag screws.
11. Install the second gate, leaving a 1-inch space between the two gates.
12. Drill pilot holes in the second fence post.
13. Fasten the hinge to the post with lag screws.
14. Remove the wedge and 2x4 blocking from underneath the gates.