USPS STD-4C — Indoor Mail Suite Systems

4C Horizontal Mail Suites —
Sized to STD-4C.
Ready for CO.

A 4C mail suite is not a furniture decision — it is a USPS-specified infrastructure system governed by STD-4C tenant door counts, parcel locker ratios, and ADA door-handle height requirements. Ironpost Works manages the full scope: compliance analysis, rough-in coordination, suite installation, and USPS sign-off, for both recessed new-construction and surface-mount retrofit applications.

Arizona ROC #366229
USPS STD-4C Compliant
ADA 28 CFR §36.304 Verified
Rough-In Coordination Included
CO-Ready Documentation
Configurations

Two Installation Types. One Qualified Contractor.

The right configuration depends on your building type, construction phase, and USPS access requirements. Ironpost Works specifies the correct approach and carries it through to postmaster sign-off.

New Construction
Recessed Installations

Integrated into the wall structure during framing — the correct approach for new multifamily and mixed-use construction. Requires coordination with the GC during rough-in so the alcove, backing, electrical (if required), and clearances are specified before drywall.

  • Pre-construction STD-4C compliance review
  • Rough-in alcove specifications for GC coordination
  • Suite sizing per unit count and parcel locker ratio
  • ADA door-handle height verification
  • USPS coordination and postmaster sign-off
  • CO-ready documentation package
Retrofit
Surface-Mount Installations

Mounted to existing wall surfaces for retrofit applications — the standard approach for older multifamily properties replacing non-compliant lobby mail systems. No structural demolition required, but existing infrastructure must be assessed for compliance gaps before specification.

  • Existing system assessment and STD-4C gap analysis
  • Surface preparation and blocking installation
  • Suite installation per current STD-4C requirements
  • ADA forward-reach and side-reach verification
  • USPS coordination and delivery activation
  • As-built documentation and compliance photos
Full Scope

What Ironpost Works Delivers on Every Suite Project.

STD-4C Compliance Analysis

Unit count review, tenant door requirements, and parcel locker ratio analysis against current USPS STD-4C requirements. Completed before specification to prevent CO-blocking non-compliance.

Rough-In Coordination

Alcove dimensions, wall backing requirements, and clearance specifications provided to the GC team during framing — eliminating costly post-drywall rework.

Permit & Engineering

Permit application and municipal submittal. Ironpost Works carries the mail infrastructure permit scope independently — no burden on the GC or property owner.

Suite Installation

Supply and installation of the 4C horizontal mail suite configured to STD-4C specifications — tenant doors, parcel lockers, and carrier access panel properly integrated.

ADA Verification

Forward-reach and side-reach measurements per 28 CFR §36.304 on every suite section. Written ADA verification included in the CO documentation package.

USPS Postmaster Sign-Off

Postmaster meeting, STD-4C compliance documentation, arrow lock procurement, and delivery activation. The project is not complete until mail service is active.

Who We Serve

Built for Developers, GCs, and Property Managers.

Multifamily Developers

New construction 4C suite scope specified and installed before CO. Pre-construction compliance review ensures no mail infrastructure surprises at final inspection.

General Contractors

Ironpost Works delivers the rough-in specifications your team needs at framing, then returns for installation. One scope, one permit, one documentation package — no coordination burden on your PM.

Mixed-Use Developers

High-rise and mixed-use lobby mail suites require precise STD-4C sizing and ADA compliance that standard finish contractors are not equipped to deliver. Ironpost Works specializes in this scope.

Planning a 4C Mail Suite Installation?

Submit your project details and we'll respond with a STD-4C compliance review, scope recommendation, and itemized pricing within 48 hours.