A sturdy mailbox post is more than just a place to hold your mail — it’s one of the first things people see when they pull up to your home. Building your own mailbox post from cedar gives you strength, beauty, and long-lasting durability. In this guide, we’ll walk through the steps to build a professional-looking cedar mailbox post with a few upgraded touches.
Why Choose Cedar Over Treated Wood?
When people buy a mailbox post, their first thought is often treated pine. While treated wood does resist rot, it doesn’t have the natural advantages of cedar:
- Natural Decay Resistance – Cedar naturally resists moisture and insects without harsh chemicals.
- Better Appearance – Its warm reddish tones and visible grain give it a much more attractive, finished look.
- Less Warping and Splitting – Cedar is more stable than treated pine, meaning fewer cracks and a longer lifespan.
- Takes Finish Well – Cedar absorbs stains, sealers, and urethanes evenly, enhancing its natural beauty.
Materials Needed
- 4×4 cedar post 8 feet long
- Cedar board (about 3/4 inch thick) for the mailbox mount
- #10 Stainless steel or coated exterior screws (3″)
- Lattice screws with finish matching the mailbox
- Copper naphthenate
- Matte or satin spar urethane
- Mailbox and mounting hardware (black or white lattice screws work well)
- Solar light cap (optional)
Tools Needed
- Circular saw
- Miter saw
- Router with long straight bit
- Drill/driver
- Countersink bit and plug cutter
- Measuring tape
- Speed square
- Orbital sander with 80 grit sandpaper
- Paintbrushes
Step 1: Cut and Prepare the Posts
Start with two 4×4 cedar posts that are 8 feet long.
From one post, cut a 54″ section to be used for the vertical beam.
From the other post, cut a 29″ section to be used for the horizontal beam and a section that’s 52″ to be used for the 45 degree support.
Step 2: Treat the Ground Section
Brush or dip the bottom 2 feet of the post in copper naphthenate. This gives extra protection against ground contact rot. Let it dry thoroughly before installation.
Step 3: Create the Mailbox Arm
Cut a notch in the post where the horizontal arm will fit. To do this:
- Make a series of kerf cuts with your circular saw to remove most of the wood.
- Clean out the notch with a chisel or router for a snug fit.
- Cut the cedar arm to length (usually 18–20″).
Chamfer the arm’s edges as well so it matches the style of the post.
Step 4: Assemble the Post
Fit the arm into the notch and secure it with exterior screws driven through the post into the arm. For a cleaner look, use a countersink bit and cedar plugs to cover screw heads. Add the mailbox mounting board on top of the arm.
Step 5: Finish and Seal
Apply spar urethane to all exposed wood above ground. A matte or satin finish keeps the natural cedar look while protecting it from UV and rain. Add a solar light cap on top of the post for a nice touch and better nighttime visibility.
Step 6: Install the Post
- Dig a hole about 24″ deep.
- Set the post in, ensuring it is level and plumb.
- Backfill with soil and tamp firmly (or use concrete if you prefer extra stability).
Finally, mount your mailbox to the cedar board using exterior screws.
Step 7: Enjoy the Finished Project!
You now have a handcrafted cedar mailbox post that looks sharp, lasts longer than treated pine, and reflects the pride you put into your home projects.