Molded Plastic Posts There are a number of choices for mailbox posts today. The most popular choice these days is molded plastic. Plastic has endless design possibilities, using flowing shapes, interesting colors and unique designs with integrated features such as newspaper holders. Some are even made to look like a real painted cedar mailbox post, but for a fraction of the price and without the durability problems. As a whole, plastic mailbox posts are extremely durable and will outlast any wood or metal post.
Metal Posts Metal posts are usually available in galvanized steel or recycled aluminum. Both are durable and strong, but the better choice is aluminum. Because recycled aluminum doesn't rust like steel, the finish will last and look good longer. However, recycled aluminum posts can be more expensive. With recycled aluminum mailbox posts you can also add matching aluminum address plaques that will enhance and change the look.
Wood Posts A wooden mailbox post is the traditional choice, especially for a do-it-yourself person looking to save money. The cheapest and simplest post is a simple 4 x 4 or 6 x 6 post of any wood variety. A one inch thick piece of pine, plywood or cedar wood base is attached to the top of the post and the mailbox is screwed onto it. The base should be sized to fit into the recess under the mailbox. On some mailboxes, you will need to leave some space at the door end of the base to prevent rubbing. Be sure to test the operation of the door before making the box installation final.
If you want a more interesting look, you can buy a fancy post with a horizontal arm, plant hangers, complex supports and other ornaments. These are available in redwood, cedar and various untreated and pressure-treated woods. There are many advantages and disadvantages to any type of wood post.
Cedar and redwood are both very insect resistant, but are quite expensive and will eventually rot if buried. They also require an underground preservative applied right at ground level.
Untreated woods such as Douglas fir and pine can be used for mailbox posts but require preservatives both above and below-grade. They have the shortest lifespan of any post, regardless of the preservative used since they have no inherent resistance to insects or rot.
Pressure-treated wood has high resistance to rot and insects due to the infusion of a powerful preservative and will last longer underground than any other wood product. However, pressure-treated wood should be treated with a protectant above ground to prevent cracking, twisting and splitting.
In the end just make sure you adhere to the rules and guide lines of your post office.You dont want to spend all that time and money to find out from your mailman you are not up to code with you installation.