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.