By Gary Anderson
Posted on Sunday, June 13th, 2021
The most common structural member for sign mountings is a post. And perhaps the most common sign use is a 4-by-8-ft. overlaid plywood panel nailed to a couple of bare 4-by-4-in. pressure-treated posts. This always bothered me because the sign looked like it was attached to a couple of little sticks. The posts added nothing to the overall look and appeal of the sign.
To avoid that look, my first effort is to at least put a coordinating color coat on them. After that, I try to beef up the mass of the post so that it becomes a noticeable, structural part of the sign. This not only adds structural integrity, whether real or imagined by adding volume, but it always makes the sign more visible and, consequently, effective.
In our area the code restricts the square footage of the sign, but does not regulate the structure that holds it up. There is always a limit to how far you can go, but rarely will posts be over-scaled. The best thing to do is trust your eye—just like you do every day when producing other signage components.
Avoid solid posts
Experience has taught me that posts made of solid redwood or cedar will rot at the ground line. Pressure-treated pine has a tendency to warp, split and is somewhat hard to keep painted, although acrylic latex does perform well when applied to treated posts. Acrylics allow the water that the post picks up from the treating process to pass through the finish.
Since neither the natural wood or treated wood work well by themselves, I often combine the two to make one good post. This gives me control over the size, paint-ability, style and longevity.
There’s no need to start with a large post just to get a more massive look. You can build a box from cedar or PVC, trim it out, then attach it to a treated post. The treated post needs only to be large enough to properly support the sign. Redwood or cedar trim should stop short of ground contact to protect it from decay.
Take a look at the drawings showing how a basic 4-by-4-in. post can be built up to a 6-by-6 using cedar or redwood. The other drawings show how different post configurations are constructed and the placement flexibility of the structural interior treated pole.
Add a post top and maybe a finial
To finish out the top of the post and protect the end grain, apply a post top. I’ve learned that the platform supporting the finial or other element does not perform well if it’s made of one solid piece of wood—expansion and contraction frequently cause splitting. The best solution is a glued-up blank of smaller pieces of wood, HDU or overlaid plywood.
Typically, I build a post top starting with a platform of overlaid plywood, then pieces of HDU—it’s a great way to use up scrap material. There’s also an array of commercially available post tops made of wood, PVC or HDU, but many are small-scale. The large post tops I frequently use must be built in-house.
Mount the face
Suspending a sign panel between two posts may seem simple, but there is more to it than one may suspect. Expansion, wind load, structural integrity, ease of installation and aesthetics all must be taken into consideration. Installing a single-faced sign can be as simple as attaching a piece of wood or a steel bracket to the post and fastening the sign panel to that. But a double-faced sign presents more of a challenge, especially if the sign face is one solid panel.
It is amazing how many different post styles can be developed to fit a situation. There’s no limit to the detailing you can do to the box you build to cover the treated post that’s actually holding the sign panels. You can add trim, cut flutes in it, add finials of all kinds—you name it. Beautiful posts are much cheaper than stone when it comes to meeting a budget, yet you can get similar mass. When the design criteria dictate wood, color or style, creative post design can deliver the look.
You’ll find more examples of Gary’s post designs in Basic Sign Structures: Posts, Boxes and Fences.
You can build a 6-by-6-in. post by nailing 1-by-4 and 1-by-6 cedar boards to a treated 4-by-4. For larger posts, you’ll have to build a box to attach to the treated post separately.
If the post is over 6-by-6-in., it should be placed where it will best serve the structural integrity of the sign and the mounting system you’re using. Any combination of readily available dimensional lumber can be used to wrap the post. Posts don’t have to be square—for a rectangular post, use whatever combination of lumber you want.
I usually build a skeleton using pressure-treated 2-by-4-in. stock between the posts to hold large double-face HDU signs. The stock is screwed, bracketed or bolted together. With this system, faces of 1-in. HDU board can be used on each side.
The treated structure roughly follows the shape of the sign. It is bolted to the treated post inside the post structure. The sign face is fastened to the framework, using screws and silicone or the fastening system of your choice.
Another typical structure is a box built around the posts to create a monolith that holds the sign faces.
To mount a double-faced sign between posts I often use a heavy-duty galvanized steel angle bracket from Steel-Brite Supply. They make a variety of brackets in steel, aluminum and stainless. The bracket has a round hole on one side and a slot in the other, making adjustments much easier. I bolt the brackets to the top and bottom edges of the sign panel at the corners, then fasten the brackets to the posts. If the sign is large, leave the posts loose in the ground until the sign panel is attached to the posts.
To cover the top of the post box, use 3⁄4-in. overlaid plywood cut to fit tightly inside the box. Nail or screw through the dimensional cedar lumber into the center of the plywood. This will give you a firm platform to attach post tops to.
Gary Anderson’s shop, Bloomington Design, is in Bloomington, Indiana. Now retired, he has contributed to SignCraft for over 35 years, and authored two books: Signs, Graphics & Other Neat Stuff and More Signs, Graphics & Other Neat Stuff, both published by SignCraft.
