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Salsbury Mailbox Blog

How to Choose the Best Wall Mounted Commercial Mailbox for Your Facility

August 10, 2023

It can be very difficult to decide what type of mailbox will best suit your facility, especially when space is limited. Luckily, with wall mounted mailboxes, you will just need a wall in or on which to install the mailbox. You may even already have a rough opening from a previous mailbox system where you can put the new mailbox.

Once you decide on a wall mounted commercial mailbox, there are still several different types to choose from. Which one works best for you will depend on a number of factors—what type of facility you own, what color mailbox you want, and the level of security you’re looking for all play a role in deciding what type of mailbox will work for you. In this guide, we will walk you through the process of choosing the best wall mounted commercial mailbox for your facility.

Types of Wall Mounted Commercial Mailboxes

The types of wall mounted commercial mailboxes you can choose from are 4C horizontal4B horizontal, and 4B vertical. Here is some information about each type of mailbox to help you decide which one would suit your needs.

4C Horizontal Mailboxes

4C horizontal mailboxes are required for new construction and major renovations. So if you are building a new facility, this is the type of mailbox you will need to install. A “major renovation” occurs when the wall where the existing mailboxes are installed is being substantially modified—this is another case where you will need a 4C mailbox.

Salsbury Industries 4C mailboxes are constructed of heavy-duty aluminum and stainless-steel hardware and are available in configurations that are one door wide (single column) and two doors wide (double column). You can choose between recessed mounted mailboxes and surface mounted ones. Recessed mounted mailboxes are designed to fit into a rough opening while surface mounted ones are designed to be mounted on a wall or other flat surface. Note – For access by the U.S. Postal Service on surface mounted units, contact your local postmaster for approval.

The Salsbury recessed mounted 4C horizontal mailboxes come in four different heights: six door high, ten door high, eleven door high, and Maximum Height units. They are USPS approved and are available with front and rear loading compartments. They can be used for indoor and/or outdoor centralized mail delivery. Each unit has a compartment for outgoing mail collection which includes a mail slot and weather protection flap.

Mail carriers can access Salsbury surface mounted 4C mailboxes from the front through one or two easy opening master door panels. They also can be used for indoor/outdoor centralized mail delivery and include a compartment for outgoing mail collection which includes a mail slot and weather protection flap.


4B Horizontal Mailboxes

Salsbury 4B horizontal style commercial mailboxes are designed for replacement and retrofit installations. This means that you won’t be making any significant modifications to the rough opening where the existing mailboxes are installed. Salsbury 3600 series 4B horizontal mailboxes are made entirely of aluminum and are USPS approved. They feature a durable powder coated finish in 3 colors, aluminum, bronze and sandstone.

The 3600 series 4B horizontal mailboxes are recessed mounted and come in front loading units or rear loading units. These mailboxes have been USPS approved for the required security upgrades of USPS-STD-4B . Effective October 2006, 4B horizontal mailboxes are approved for replacement and/or retrofit installations.


4B Vertical Mailboxes

Like 4B horizontal style commercial mailboxes, Salsbury 4B vertical style commercial mailboxes are designed for replacement and retrofit installations. They too are made entirely of aluminum and feature a powder coated finish in aluminum, bronze, and sandstone.

They are available as recessed mounted or surface mounted units. They feature 5-1/2” W x 16-1/4” H extruded aluminum doors. Each door includes a five pin cylinder cam lock with two keys and a 2-1/2” W x 5/8” H indentation to accommodate a label with the tenant’s name and/or box number. Mailboxes come in units with three to seven compartments. Each compartment is 6-3/4” D.


Best Wall Mounted Apartment Mailboxes

4C horizontal, 4B horizontal, and 4B vertical mailboxes are all great mailboxes for apartment buildings. It just depends on what your particular needs are. As said, 4C mailboxes are required for new construction or major renovations—so if you are constructing a brand new apartment building or making a major renovation to the rough opening where your current mailboxes are installed, you will need to purchase a 4C horizontal mailbox.

If you’re not making significant changes to the rough opening where your existing mailboxes are installed, 4B horizontal or 4B vertical mailboxes might be the right choice for your apartment building. Surface mounted 4B vertical mailboxes are ideal when wall depth is limited, while recessed mounted ones work best when a flush mounted installation is preferred.

Best Wall Mounted Mailboxes for Businesses

4C horizontal, 4B horizontal, and 4B vertical mailboxes not only suit apartment buildings but will also work well for your office. Wall mounted units don’t take up any space and are therefore perfect for a busy office environment. As with apartment buildings, the type of mailbox you choose will depend on whether or not your office building is undergoing new construction and/or major renovations.

What Color Wall Mounted Mailbox Works Best for Your Facility?

An important factor to keep in mind when choosing a wall mounted commercial mailbox for your facility is the aesthetics of your apartment or office building. You want your atmosphere to look sleek and pleasing to the eye—that way, a potential tenant might be more likely to rent an apartment or a business associate will be impressed by the look of your office.


No matter what look you are going for, Salsbury Industries will be able to provide mailboxes that suit your aesthetic. Our 4C recessed mounted and surface mounted mailboxes come in aluminum, black, bronze, and sandstone. Our 4B horizontal and 4B vertical mailboxes are available in aluminum, bronze, and sandstone.

If these colors don’t match your facility, don’t worry! We carry 4C custom horizontal mailboxes and 4B custom horizontal mailboxes, each with a broad range of custom colors available. These mailboxes come in front or rear loading units.

How Many Mailboxes and Parcel Lockers Do You Need for Your Wall Mounted Mailbox?

If you are the owner of an apartment building, there should be one mailbox per apartment in your building. If your mailbox is for an office building, the number of compartments you need really depends on who in your building receives mail.

Effective July 2020, the USPS-4C Standard requires a 1:5 parcel locker to customer compartment ratio. So there should be at least one parcel locker for every five mailbox compartments.

What Are the Most Secure Wall Mounted Mailboxes?

4C mailboxes are made of heavy duty aluminum and stainless steel hardware that will keep your tenants’ mail safe. According to USPS specifications, STD-4C mailboxes must have locks where the hole has to be able to withstand 100 foot pounds of rotational torque, preventing the lock from being turned in the door and allowing unauthorized entry into the compartment.

Parcel lockers also help to protect tenants from theft. Instead of leaving a package in the lobby or outside where anyone could easily steal it, mail carriers are able to place packages in a parcel locker. They leave the parcel locker key for the tenant and then later, when the tenant retrieves their package, the key locks in place and can only be removed by the mail carrier.

Where to Buy Wall Mounted Mailboxes

No matter what your needs are regarding wall mounted commercial mailboxes, Salsbury Industries is sure to have just the right one to suit your apartment or office building. We offer a wide range of sizes and colors that will be both beautiful and functional. Your tenants can feel safe and secure with sturdy mailboxes that will keep their mail and packages safe.

After reading this post, you will hopefully have a better idea of which type of wall mounted mailbox will work best for your facility. Check out our 4C horizontal mailboxes here, our 4B horizontal mailboxes here, and our 4B vertical mailboxes here.