A sagging wooden gate is a nuisance at best, and can, at some point, become impossible to open. The problem must be pretty common, because someone has already packaged and marketed a repair kit for exactly that purpose. It’s called a gate repair kit or turnbuckle kit, and it consists of a cable with corner mounting brackets and a turnbuckle. The nice thing about a turnbuckle kit is that it can be tightened or loosened to raise or lower the gate.
The kit contains:
Two metal corner brackets with mounting nails
Two lengths of wire cable with galvanized metal U-bolts, which are used to attach one end of each cable to one of the corner brackets and then the other end of each cable to the turnbuckle
A galvanized metal turnbuckle
Here’s how it works:
Attach a metal bracket to the upper corner of the gate (on the hinge side).
Mount another bracket diagonally at the lower corner of the gate on the latch side.
Attach cables to each corner bracket and then to the two ends of a turnbuckle.
As you tighten the turnbuckle, the latch side of the gate rises. As you loosen the turnbuckle, the latch side of the gate drops.
This system won’t work if the upper bracket isn’t placed on the hinge side of the gate.