How to Build a Custom Mailbox

How to Build a Custom Mailbox

A custom mailbox can be a fun, DIY project that can add a lot of curb appeal to your home. Additionally, by building your own mailbox, you can customize it any way you want!

To build a custom mailbox, start with design. After visualizing and planning out your custom mailbox, begin constructing the mailbox using pressure treated lumber and exterior rated screws. Mount your mailbox in the ground so that it sits approximately 41″-45″ above grade.

This article will teach you everything you need know so you can build and install a custom mailbox like the one I made below:

This article will teach you how to build this mailbox
This article will teach you how to build this mailbox

1. Design Your Mailbox

Plan Out Your Design

The key to a building a beautiful, high quality mailbox starts with Design. Before you begin building your custom mailbox, spend some time thinking about the design elements. A few things to think about include:

  • Style of mailbox
  • Size of mailbox
  • Ease of Constructability

When planning my custom mailbox design, I started with a pen and paper and sketched everything out. This sketch gave me a good idea of what I would need to do in order to complete my design. Additionally, it gave me a good feel for what materials I would need to purchase.

When designing your mailbox, keep the following things in mind:

  • Your mailbox should be roughly 41″-45″ above grade
  • Ensure that you have 18″-24″ of your mailbox anchored in the ground

Now, let’s take a look at purchasing your mailbox construction materials.

2. Purchase your Materials

Once you have designed and sketched out your mailbox, it’s time to purchase your mailbox construction materials. Obviously, the materials you will need will depend on the design and style of your mailbox you choose. However, some common materials you will need are listed below:

  1. Pressure treated lumber
  2. Screws
  3. Mailbox
  4. Concrete Mix (if applicable)
  5. Stain or Paint
  6. Paintbrushes
  7. House Numbers

Once you have purchased all of the materials for your custom mailbox, you can begin construction!

3. Construct the Mailbox

At this stage, construction of your custom mailbox can begin.

Start by cutting your materials down to size by using a miter saw or circular saw.

Start by cutting your materials down to size by using a miter saw or a circular saw
Start by cutting your materials down to size by using a miter saw or a circular saw

For my mailbox design, I cut my 1″x6″ pressure treated lumber down to rough size and then laid them out as shown below.

Lay out your materials to get an idea of how the final mailbox will look
Lay out your materials to get an idea of how the final mailbox will look

At this point, I used a pencil to mark the “curvature” of my mailbox.

I used a pencil to mark out the curvature of my cuts
I used a pencil to mark out the curvature of my cuts

Next, I used a jigsaw to cut the 1″x6″ pressure treated lumber along the marked “curvature” line.

Cut lumber along your marked line
Cut lumber along your marked line

After cutting all of the 1″x6″ pressure treated lumber along the curved line, I fastened them to a 4″x4″ (that I painted black) using exterior rated screws. I used a 1″x6″ piece of lumber to serve as a spacer.

Fasten your 1"x6" pieces to a 4"x4"
Fasten your 1″x6″ pieces to a 4″x4″

After fastening all of the 1″x6″ lumber to your 4″x4″ mounting post, consider using a piece of plywood to prevent bees or birds from making nests within your mailbox. I used a piece of 1/4″ plywood (again, painted black) and marked it along the 1″x6″ curved line.

Mark your plywood along the cut line
Mark your plywood along the cut line

Next, cut your plywood along the cut line with a jigsaw and then insert it back inside your mailbox. Fasten the plywood to the 1″x6″ lumber using screws.

 cut your plywood along the cut line with a jigsaw
cut your plywood along the cut line with a jigsaw

For my curved design, I needed to bend a 5/8″ thick piece of pressure treated fence picket so that it could be fastened to the front of my mailbox. In order to bend the fence picket, I used a 50 pound bag of marble chips and hot water.

I used a 50 pound bag of marble chips and hot water to bend my fence picket
I used a 50 pound bag of marble chips and hot water to bend my fence picket

After sufficiently bending the fence picket, I used clamps to mold the picket in place on the font of my mailbox. Once the picket was positioned appropriately, I fastened it to the mailbox with screws.

Attach the bent fence picket to the front of your mailbox using clamps and screws
Attach the bent fence picket to the front of your mailbox using clamps and screws

Next, cut off the top of the fence picket so that it is flush with the rest of your mailbox.

Use a circular saw to cut the fence picket flush with the mailbox
Use a circular saw to cut the fence picket flush with the mailbox

The last step in the custom mailbox construction process is to attach your mailbox using screws.

Attach your mailbox to the mailbox base
Attach your mailbox to the mailbox base

Once your custom mailbox has been constructed, it’s time to install the mailbox in the ground.

4. Install the Mailbox in the Ground

At this stage, it is time to install your mailbox in the ground. As mentioned previously, your mailbox should be anchored approximately 24″ below grade.

Use a shovel or a post hole digger to excavate down approximately 24″.

Use a shovel or a post hole digger to excavate down approximately 24"
Use a shovel or a post hole digger to excavate down approximately 24″

Once you have dug your hole, position your mailbox in place and ensure that the height of the mailbox is appropriate. Once you are happy with how your mailbox looks, mix up some concrete and apply it to the mailbox hole.

Mix up concrete so that you can anchor the mailbox in the hole
Mix up concrete so that you can anchor the mailbox in the hole

Be sure that you check your local code requirements regarding concrete anchoring of your mailbox. If you live along a busy road, it may not be allowable for you to use concrete to anchor your mailbox since it could present a risk to drivers.

Position the mailbox with the ground and ensure that it is level
Position the mailbox within the ground and ensure that it is level

Once your mailbox has been mounted in place and you have filled the annular space with concrete, use a post level to ensure that your mailbox is perfectly plumb. Once you are comfortable with how your mailbox looks, allow the concrete to cure.

5. Stain, Paint, or Decorate your mailbox

Once your concrete has fully cured and your mailbox is secure, you can begin to stain and and decorate your mailbox as desired.

For my mailbox, I used gel stain to give my mailbox a weathered look.

Apply Stain or Paint to your mailbox as desired
Apply Stain or Paint to your mailbox as desired

After staining the mailbox and allowing the stain to dry, I applied house numbers to my mailbox.

Add house numbers to your mailbox as desired
Add house numbers to your mailbox as desired

Lastly, I applied a cut piece of 4″x4″ to the back of the mailbox to help with the aesthetic.

Apply a piece of wood to the back of the mailbox, if desired.
Apply a piece of wood to the back of the mailbox, if desired

At this stage, your custom mailbox build is complete! If you followed the steps in this article, you should now be the proud owner of a beautiful, custom mailbox, similar to the one you see below:

Completed Custom Mailbox
Completed Custom Mailbox

If you are more of a visual learner, you can watch me build this mailbox from start to finish on Youtube:

Thanks so much for checking out ATImprovements! If you learned something from this project, you might also like these other DIY Projects:

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Thanks!

DISCLAIMER: This is a reference guide only. Links included in this article might be affiliate links. If you purchase a product or service with the links that I provide I may receive a small commission. There is no additional charge to you! Thank you for supporting ATimprovements so I can continue to provide you with free content each week!

Andrew Thron

Andrew Thron has established himself as an expert in the field of home renovation helping millions with their DIY home renovation and home improvement projects through detailed YouTube video tutorials, Instagram project ideas, and step-by-step blog articles.

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