3 common mistakes made when installing u-channel sign posts
These signs look terrible. So, what happened here? I found three big mistakes when investigating the installation of these u-channel sign posts. There might have been a fourth mistake as well. I wasn’t there when they installed these posts, but they could’ve installed them crooked in the first place, but that is unlikely ..but that would be the fourth mistake. Here are the known mistakes…
Mistake #1 was that they weren’t installed deep enough into the ground. I pulled one out and found they were only about 24 inches deep. In our area, posts should be 36 inches deep to get below the frost line and avoid something called “frost heave”. The frost line is different in every area of the country. Do a google search for “frost line map” and you’ll find a map showing the depth of the frost line in your area. If you’ve ever squeezed a watermelon seed between your fingers and shot it across the room then you understand the principle behind “frost heave”. Even in warm climates I’d go 36″ deep and then go even deeper for cold climates to get at least 3 or 4 inches below that area’s frost line.
Mistake #2 was going with a 1.12 lb post. A lot of people use these for signs, but their intended purpose is to hold reflective delineators. I see them used for signs everywhere. I recommend a 2 lb post for parking signs. A 2 lb post is a post that if cut into a 1 foot long section would weigh 2lbs. So, with that in mind you’ll see that the 2 lb post uses almost twice the steel of a 1.12 lb u-channel post. When inspecting the posts pictured above, some were actually bent at the point where the post went into the ground.
Mistake #3 had nothing to do with how crooked these sign posts are. Mistake #3 was how they installed their signs. The posts make a “U” shape when viewed from above. In that “U” shape, the sign would go along the top of the “U” and not the bottom. When you bolt them against the bottom of the “U” shape they are less stable and can rock back and forth easier than if installed against the top of the “U” shape.
In conclusion, installing u-channel posts isn’t rocket science. It is super easy if you’re aware of just a few common mistakes. Once you’re aware of the mistakes you’ll see just how common they are.