How to Build a Wood Gate That Doesn’t Sag

There’s surprisingly little good instruction anywhere on how to build a wood gate properly — it’s not well covered in books, and it’s arguably the single biggest weak point in the fence-building trade. Sagging gates with hardware that no longer closes properly are, by a wide margin, the most common flaw seen in wood fences.

Every wood gate needs a diagonal brace, and braces work by compression — meaning the direction they run matters enormously. The correct orientation runs from the swing side of the gate down to the hinge side. It’s common to see braces installed the right idea but backwards, which defeats the entire purpose: a brace running the wrong direction does nothing to stop the gate from racking and sagging over time.

Sizing matters just as much as bracing direction. A gate built with the right bracing but oversized for its hardware and posts can end up too heavy to operate properly, even with everything else done correctly.

Hardware choice matters too — many common gate brackets don’t perform well over time, and some react chemically with modern ACQ-rated pressure-treated lumber, accelerating corrosion at exactly the point carrying the most load.

When a gate isn’t hung directly off a wall, a headpiece connecting the hinge post to an adjacent post is often necessary — without it, the cumulative weight of the gate slowly bends the hinge post itself, which throws off the hardware alignment and causes the gate to rub or bind against the ground or the latch post.