DIY Mailbox Post

Introduction: DIY Mailbox Post

I decided to make a new mailbox post and replace our old box and post to add some curb appeal to the front of our home. This is a GREAT project for those new to woodworking and on a budget. I completed the entire project for under $100 and this includes the post, a new box and custom made decals to apply to the sides of the box with our last name and address. Another goal was to make the new mailbox match our newly painted front door!


For this Project you will need 1 = 8ft 4x4 material of your choice, for my post i chose cedar but you can commonly find treated pine 4x4 material at any big home center store.

A saw of some sort, I used a miter saw, and table saw in this construction as well as a plunge router for my choice of joinery in this build (mortise and tenon) But you could accomplish this with only a hand saw and a drill if necessary.

Wood Glue

And if you choose to add a new box you will also need one of those.

If you are replacing the mailbox itself, you will also need a piece of wood to attach the box to (whatever length and thickness will be required to fit underneath the mailbox mount area. Wood screws (various lengths)

Step 1: Draw Out Your Plans

You can choose to make a 3D model for this simple project (but for me i just drew it on graph paper) Get your measurements and cuts laid out to ensure a seamless workflow.

Step 2: Cut All Your Major Components

After making your plans and getting your measurements, begin to cut out all pieces for the main post construction. For this simple design, I only had 4 main pieces: the main post, the piece to support the box, the support piece (with the two 45 degree cuts) and the small piece of wood to actually attach the box to the post.

Step 3: Layout and Cut the Joinery

For my build, i chose to use mortise and tenon joints for added strength but the connections could simply be made with wood screws if you so choose. Using screws along with glue will make for a strong enough joint but make sure to use screws rated for outdoor use (such as deck screws)

Step 4: Assemble All the Parts & Components

Glue , screw and otherwise assemble all of the pieces. If you use glue, make sure to add clamps and allow glue to cure fully before putting the post in the ground. When mounting the smaller board that the box attaches to, make sure to open and close the mailbox door so you can be sure the door has enough clearance to open and close properly.

Step 5: Apply a Water Resistant Finish

If you are using an untreated material (as i did) You will need to apply some sort of water resistant finish to the post itself. I used a Spar Urethane, which has great water resistant properties and meant for use in the marine field for coating boats. This finish will give the wood several more years of durability with the abuse that any piece will take in being outdoors. Water and UV rays reek havoc on wood so anything that can give some protection will help your new project to last much longer.

Step 6: Remove the Old Post

With my post it was simply inset into a hole, but if you have a mailbox that has been set into concrete, you will have to dig out the concrete surrounding the base of of the post. If it is simply placed into the hole, you will need to merely wiggle the post back and forth and side to side until it is loose enough to lift from the hole.

Step 7: Install Your New Mailbox Post

First i made a small mark around each side of the post for 20 inches , which is required where i live. Then i set the new post back into the old hole, adding a little dirt, then a bit of water and all the while tamping the dirt around the post as i went. I continued this process over and over to cover a few inches at a time to make sure the post was well seated into the hole. Make sure to keep a level handy and check that the post remains level throughout the installation process.

Step 8: Install the New Mailbox Onto the Post

The installation of the new mailbox is overwhelmingly simple. I used 8 stainless steel screws to attach the box to the platform on top of the post. This process may vary depending on the mailbox you choose for your project.

Step 9: Enjoy Your New Mailbox and Post and Go Watch the Video for More Information

Now you ( and your neighbors ) can enjoy your new mailbox and post. If you want to see the full in depth build, you can go watch the video embedded here. If you have any questions please feel free to leave them in the comments on the video or send me a message or comment here on Instructables!


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    2 years ago on Step 8

    Upper part of post construction well done here. Popular design of running the post up behind back of mailbox is unnecessary, even stupid in most cases, it just makes the construction top heavy and susceptible to tilting.

    However the bottom as shown above does not protect from freeze-thaw/termite/rot/string trimmers. Look around your neighborhood: wooden posts are tilting and chewed up at ground level.

    The solution is first to wrap buried part of post with adhesive backed roof wet proofing wrap, plus sheet metal to extend 4" above grade, caulk the top of sheet metal against wood post, then paint or tar-coat sheet metal. Then oil the post and let it weather gray.

    Dimensions Wood Works
    Dimensions Wood Works

    Reply 1 year ago

    Each person’s mailbox post will assuredly be different based on region. I live in South Mississippi so i never have to worry about fault lines or the ground freezing/thawing. If you live somewhere snow is common i see many folks making their post from metal and able to swivel due to snow plows constantly hitting them while clearing roads in deep snow. My only concern is wood destroying insects 🐜 and for me, here, that mostly means termites and carpenter bees 🐝 That’s why I chose the Cedar for the construction as no common insects here will eat it. And it holds up well to water also.
    These projects are just my experiences in my area and all aspects won’t pertain to everyone but if i can help a few folks accomplish a simple task, i consider that Mission Accomplished.

    Thanks for checking it out.


    Reply 1 year ago

    200 miles +/- North of you, carpenter bees eat holes in my Western Cedar exposed lintels, set in brick over windows, and termites have eaten up a large pile of my Eastern Red Cedar (Juniper family) lumber, all heart wood. Nevertheless, I am using a 4 X 6 all heart Red Cedar post, wrapped in self-adhesive roll flashing and sheet metal up to 4" above grade for a new, heavy steel powder coated mailbox where the previous aluminum was run over by a driver who was texting or drunk. The next idiot will have serious front end damage.

    But I agree regional location is relevant. Also like the fact that your design does not have a post running up behind it like most stupid designs for sale. In my area, string trimmers eat away wood posts at grade, followed by rot and insects. These are frequently tilted and unstable after little time in the ground.

    Out in my previous home of arid Colorado, fence posts in the ground can last 50+ years, where I worked one summer on an historic ranch and replaced many ancient posts.