Posted on Wednesday, February 28th, 2018
The posts for this sign were installed using a post anchor system called Oz-Posts, which are galvanized steel post anchors that you drive into the ground— without digging a hole. They are 3-ft. long and taper to a point, and are available at many building materials stores. You drive them in with an electric jackhammer using a special fitting on it. Then you insert a post into the Oz-Post and screw or bolt through it to secure the post. They come in 4×4, 6×6, 8×8 and 10×10 post sizes, for round or square posts.
There are several advantages to this method over digging holes. First, since you drive the Oz-Post into the ground, you aren’t trying to backfill and pack dirt around the post, so they’re much more stable than a dug hole. They’re also removable— you can pry them right out of the ground and reposition the post. If they hit a rock on the way in, they usually deflect and you can continue driving them in.
I can drive an Oz-Post right into frozen ground, too. In Vermont, it’s not uncommon to have two feet of frozen dirt to dig through in midwinter. It’s like two feet of concrete.
To drive in the Oz-Posts, I use an electric jackhammer powered by a portable generator. Even in midwinter, I can install a sign with this system in 20 or 25 minutes. In frozen dirt, it can take four hours to dig two holes. The dirt comes out in chunks just like concrete.
I’ve been using them for five or six years with no problems. They save a lot of time and work great. The only time I don’t use them is if the sign has a large surface area and is in a high wind area, or if the posts are over 8 feet above grade.
I’ve often gone back to check the installation in the spring to see if the posts might be loose, but they’re always fine. I’ve had a couple in windy locations lean a bit over time, but I just pulled them out and reset them. It’s a very practical system.
Doug Bergstrom, Xtreme Grafix, St. Albans, Vermont