Skip to Content

DIY Mailbox Tutorial

Sharing is caring!

The first thing you see when looking for a house is the mailbox; therefore, I decided to update it by creating a DIY mailbox to increase the curb appeal.

I chose the same type of wood as our other outdoor structures (trellis, lanterns, obelisk, wooden shutters, and flower box).

If you have been following my blog, then you know I am obsessed with solar lights, so I had to add one to this DIY modern mailbox.


DIY Wooden Mailbox with solar light mounted in a flowerbed

DIY Mailbox


This post contains affiliate links. In other words, if you purchase from one of these links, I will make a small commission, but rest assured, you will not pay more for any products.  

How to Build a DIY Mailbox

The first thing I had to do was to find out the requirements for the mailbox height and the best placement from the road. You can find the US Post Office requirements on their website.

4 by 4 wood posts and metal mailbox on sawhorses

DIY Wooden Mailbox supplies

Mailbox Building Supplies

4x4x8 pressure treated 2 each

1x6x8 pressure treated 6 each

2x8x20 inches pressure treated

Concrete two 40 lb bag

5-inch screws, 2 each

4-inch deck screws (4 each)

2-inch galvanized finish nails

1-inch stainless steel screws (4 each)

Mailbox 7x8x20


Miter saw

Skill saw

Impact driver and driver tips

Nail gun

Post hole digger



Speed square 

Measuring tape

Speed Horses


DIY Mailbox Posts


Measuring lumbar for mailbox posts

Measure and mark posts


For the posts, we used pressure-treated 4x4s. 

We cut the 4x4x8s into the following lengths 65, 54, and 12 inches.

To provide a stable area to attach the short boards on the back post, we screwed the 4x4x12″ to the 4x4x65″ together, aligning the tops.


Short side boards attached to the back post

Short boards on the back post

Building the Mailbox Sides

Next, cut fourteen 1x6x25 inch and four 1x6x7 inch pressure-treated boards.

Then, attach the 1x6x7″ boards to the upper portion of the back post with 2-inch galvanized finish nails.

You will want to use a speed square to keep the sideboard square to posts.  

Next, place the posts parallel to each other, keeping them 25 inches apart (outside measurement).

Then attach the side boards to the front and back posts starting below the 7″ boards using with 2-inch galvanized finish nails. 

Long and short side boards attached to both posts

Side view of the long boards on posts

Please note: this view is of the first side of the wooden mailbox holder. Once you finish this side, you will repeat the process on the other side.

Top view of one side of the mailbox assembly

Top view of posts and the first side of the mailbox

Next, we marked the trim for the inside of the back post. Note: we will attach it later.

Marking the length of the trim board

Marking the trim piece

Next, turn over the wooden mailbox assembly and repeat the same process as the other side.

The unfinished side of the mailbox assembly face up on sawhorses

The unfinished side of the mailbox assembly

Wooden Mailbox Trim – Sides

To create finished edges, we used 1×6 pressure-treated lumber.

First, we measured the assembly to get the exact sizes for our side trim cuts.

Note: lumber varies in size. 

These are the side trim cuts we used: long front 1x6x38.5, short front 1x7x6, and back 1x6x49.5

However, these measurements could vary, so you must measure your wooden assembly for the exact measurements. 

Next, attach the side trims with 2-inch galvanized nails.

Positioning the front trim board on the wood mailbox assembly

Attaching front trim board

Top Trim

We added the top trim last since we wanted it to extend to cover the side trim boards.

Therefore, you will want to include the installed side trim in your measurements for the top trim boards.


Positioning the long top trim board

Attach the long top trim board

Mailbox Mount

Next, we created a mailbox mount (AKA shelf) with a 2×8.

First, we measured the width and length of the metal mailbox then we cut the board to size. 

Then, we mitered the front edge of the mount board at a 60-degree angle to allow the mailbox to open.

Bottom view of mailbox mount board

Mailbox mount


Mitered wood mounting board with the Mailbox door open

Mitered mailbox mounting board


At this point, you will want to check the fit of your metal mailbox on the “shelf” of your wood mailbox holder.

Positioning the metal box to check for fit

Check metal box fit

Note: We installed the metal mailbox onto the mounted board using 1-inch stainless steel screws through the holes in the bottom lip of the mailbox. We did this after it was installed in the ground. 

DIY Mailbox Install 

To install the mailbox, we dug two holes 16 inches deep and 25 inches apart.

Then we placed the box posts into the holes. We backfilled the holes and then checked them for level.

Once it was level, we added the dry cement and water as we went. Next, we packed the cement around the posts and sloped it away from the wood. 

Measuring the distance between the post holes for installation

Measure the holes for install


Placing the wooden DIY mailbox assembly into the holes

Place wood assembly into holes.


Checking the assembly with a level to ensure it is plumb

Use a level to check that the installation is plumb.


Pouring concrete into the holes around the posts

Use concrete to secure posts.


Using an impact driver to screws to attach the metal box to the wooden mount board

Attach the metal box to the DIY wood mailbox assembly

Mailbox House Numbers and Solar Light


House numbers

Solar light

Since I am obsessed with solar lights, I decided to use one to illuminate the house numbers. 


Metal house numbers, pencil, measuring tape and drill on the ground

House numbers and tools for installation


Measuring and marking the solar light placement on the side of the wood mailbox

Measure and mark the side of the DIY Mailbox for installing the solar light


Attaching the house number with screws and drill

Attach house numbers


Night view of the DIY Modern Mailbox with a solar light

Night view of the DIY Modern Mailbox


See you soon,



Ps. This post has been shared on Between Naps on the Porch.



















This site uses Akismet to reduce spam. Learn how your comment data is processed.

Tuesday 27th of February 2024

1-1 waitfor delay '0:0:15' --

Tuesday 27th of February 2024

1-1); waitfor delay '0:0:15' --

Tuesday 27th of February 2024

1-1; waitfor delay '0:0:15' --

Tuesday 27th of February 2024


1-1); waitfor delay '0:0:15' --

Tuesday 27th of February 2024


This site uses Akismet to reduce spam. Learn how your comment data is processed.

Sharing is Caring

Help spread the word. You're awesome for doing it!