Direct Cluster Mailboxes

Since 2006, new construction and major renovations require STD-4C compliant mailbox systems. What this means is that 4C horizontal mailboxes and parcel lockers must be installed during new construction and major renovations, pending a discussion with your local Growth Manager. These mailboxes are flatter than previous models and incorporate stand-alone parcel locker options. At least one parcel locker must be present for every ten tenant compartments, but are not required for units containing less than ten tenant compartments.

While new construction requires the use of 4C units, mailboxes that are being replaced may be able to use 4B+ or vertical units. It’s best to check with your local postmaster before you complete a renovation project.

What is a Major Renovation?

A major renovation occurs anytime the wall is being modified where existing wall-mounted units are installed. In other words, if the rough opening of the wall is being changed, this would constitute as a major renovation.

If that rough opening will be remaining the same, you are not required to convert to STD-4C mailboxes.

STD-4C Requirements

There are certain mailbox specifications that must be met in order for you to comply with the USPS guidelines.

·        12”W x 15”D x 3”H is the minimum size requirement

·        1 parcel locker required for every 10 tenant compartments

·        ADA compliant

·        Increased security requirements

·        Improved tenant compartment lock design

·        Testing requirements to see if unit is suitable for indoor/outdoor use

You can find the full details on the USPS website.

Residential Applications

While the USPS prefers the most efficient mode of delivery, not all new residential developments must comply to the centralized delivery system standard. When building, connect with the local USPS Growth Manager to go over the specifics of your project.

Homes being built in more rural areas, for example, are not likely to be required to meet the CBU guidelines. There is no strict mandate when it comes to the size of the development property, so be sure to touch base with a Growth Manager.

The Postal Service will consider input from all parties involved in the planning process before issuing a final decision about mailboxes and mailbox placement.

Mailbox Approval

Email Delivery.Growth@usps.gov to identify your coordinator and get in contact them before you finalize any of your building plans.

The USPS will not start mail delivery until your coordinator has approved not only the mode of delivery but the location of the mailboxes. While they will work with you during all stages of development, we recommend speaking with them early in the process.