Why Does A Gate Sag?

Asian Contemporary Style Wooden GateBeing married to a (wood) gate builder has been quite an education! Because 360 Yardware deals with gate hardware every day, I thought it might be interesting to marry the two issues and discuss why a gate sags and what can be done to prevent your gate from sagging.

I must add a disclaimer that my husband the gate builder comes to gate building from furniture-making. Therefore, he is a crazy stickler for structure, function, and joinery. And it’s rubbed off on me, so I’m biased toward door-type gates (and, of course, really high quality gate hardware).

To have the best possible non-sagging gate 10 years in the future, here is the key: buy or build a well-constructed gate and have it installed by a skilled installer. In other words, the reason that gates sag is because the gate falters or because the installation wasn’t done well enough.

A Well-Constructed Wooden Gate

What is a well-constructed gate and how do you know you’re buying one? I’m going to describe two ends of the spectrum; there are endless variations within those bounds.

A well-built wood garden gate will have a furniture-quality joint: mortise and tenon, lap joint, etc. Think about your home’s front door: it’s built with nice tight joints and will last years and years, even being opened and closed many times a day.  A quality wooden gate should do the same, though it likely won’t last as long as a front door because a gate is subject to sun, rain, snow and wide temperature fluctuations. You won’t see any metal fasteners on a furniture-grade gate (screws or nails) because the joints do that work.

Well-built wooden gates are absolutely more expensive to buy; however, if you’ll get a 10-year life out of that gate versus a 3-year life out of a less costly gate, it might just be worth the expense (and the hassle of re-installing a gate every few years). And don’t discount the value that an architecturally complementary gate adds to your home and your curb appeal. I’ve seen so many million dollar homes with shoddily constructed gates that make me scratch my head and wonder why they would do such a thing to their beautiful house.

Driveway Gate with 10" Dark Bronze Thumb Latch & Dummy Handle

Now to the second category of wooden gates: the carpenter gate.  This is your typical picket or panel gate with a diagonal bracing piece across it. It’s usually constructed with 2×4’s as the frame. They are nailed or screwed together. A simple butt joint (two flat surfaces butted up against each other and screwed/nailed together) is generally not going to hold a gate together for the long haul. In the world of simply-built gates, the vast majority will have joints that won’t last. It all depends on your gate builder. An experienced gate builder can build a sturdy carpenter gate. But there’s little likelihood that this type of gate is going to last the way a high-quality gate will.

A Saggy Gate
A Saggy Gate

What About Anti-Sagging Kits? These can help hold a gate square if you’re seeing a shift in the joints.

Over time and with the gate opening and closing, the nailed or screwed joints will begin to loosen. This will cause the gate to “sag” or more accurately, lean to one side, away from the failing joint.

How to Install a Wooden Gate (Well)

A knowledgeable gate installer is a worthwhile investment. Here are some factors during the installation process that can help prevent gate sagging and give you a smoothly operating gate for years to come.

  1. Post Size: Though I don’t think anyone’s compiled this kind of data, I would venture a guess that using too small of a gate post is the major culprit in gate sagging. What makes a gate post too small? The size of the post should be related to the size and weight of the gate. Our recommendation is always a 6×6 post for standard-sized gates (~42″x70″). For driveway gates, especially those with integrated steel frames, we recommend steel posts. The key to post installation is that it be set deep enough in the ground and firmly set in concrete. If the post is not big enough to support the gate, it will start to pull in the direction of the gate. In addition, if the post isn’t set firmly in concrete, the post is going to wiggle loose bit by by in the ground. If there is one area of a gate installation that you’re going to “over-engineer” let it be the post. In areas where there’s a severe freeze over winter, trade professional have standard depths that they sink posts to.
  2. Hinge Choice: Choosing a hinge that will support the weight and style of your gate is crucial to a long-term installation. We’ve written a blog post about hinge choice that covers everything you need to know. An undersized hinge’s screw can slowly work loose from the post with the weight of the gate swinging back and forth. Heavy duty gate hinges are affordable and easy to install.