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Installing a Post Mailbox

If you live outside of an urban area, you may need to have your mailbox on a post at the side of the road. And you’re usually the one responsible for setting it up and maintaining it. Or you may have to replace one after someone accidentally runs it over.

Before starting, though, it’s important to know what you’re doing. There are requirements from the postal service. And of course, you want to be sure to install a post that will hold up over time!

Postal Service Requirements

Since we’re in the US, and most of our readers are as well, we’ll concentrate on the rules here. We suspect they’re similar in most places, but be sure to check with your national postal service to get the details!

According to the United States Postal Service (USPS), your mailbox should be positioned at a height between 41″ – 45″ from the road surface to the bottom of the mailbox or point of mail entry. The front edge of your mailbox should be 6-8″ from the curb. If you do not have a raised curb, place it 6-8″ from the edge of the road.

Also, the mailbox itself has to be approved by the postmaster. They’re usually sold with that certification stamped onto them. And in case you didn’t know: your mailbox is for US mail only. No one else is supposed to use it for the newspaper, flyers, or anything else.

Digging Yourself A Hole

Once you have checked the legal requirements, it’s time to start digging the hole for your mailbox post.

Before you start digging, make sure to contact an expert to locate your utilities. Your township is the best resource for this. This will help you avoid hitting water pipes, power cables, or other important utilities. 

Putting The Post In Place

You’ll need a 4×4 post made of treated wood that measures about 60 inches long. We discourage metal posts; in case of a car accident, a wooden post will snap, while a metal one could make the accident even worse.

Use a post-hole digger to dig a hole around 20-24 inches deep. Do not dig deeper than 24 inches. Add approximately 4 to 6 inches of gravel to the hole.

Next, insert the mailbox post into the hole. Prop it up with temporary support beams on all sides, extending around the outside of the hole. Make sure these are secure and will not shift as you pour concrete into the hole. Measure the height of the mailbox above the ground to ensure it’s around 42 inches. Use a level to ensure the mailbox post is straight. (There are a lot of great apps for that, so you can use your cell phone as a level!)

Once your post is in place and level, it’s time to secure it. Pour concrete powder into the hole, leaving 4 to 5 inches of space at the top. Keeping the mailbox post level, mix water into the concrete according to package instructions until it reaches a thick consistency. Cover the concrete with dirt and pack it down firmly.

Attaching The Box

After securing your post, attach your mailbox according to manufacturer instructions. Leave the support posts in place for 2-3 days so that the cement has time to harden.

As simple as that, you’ve got a new post mailbox installed! It’s a relatively simple task, and mixing the cement is probably the toughest part. 

Don’t forget to be kind to your letter carrier – make sure they always have a clear path to your mailbox whether it’s by the street or mounted on your house.