Adding a mezzanine floor is one of the smartest and most cost-effective ways to expand viable but currently unused space in warehouses, stores, and industrial facilities. Instead of moving to a larger building, companies can build upward and scale without making any extreme modifications, like adding another storey or making additions.

Regulatory bodies influence how a mezzanine can be constructed, and as with any structural addition to a building, mezzanine floors are subject to strict US building regulations. Structures that aren’t code-compliant face legal repercussions, including fines, building delays, and even criminal charges.

This guide will look at what a mezzanine floor is, how to design one under US codes, and the steps you need to take to ensure compliance in 2025.

What Is a Mezzanine Floor?

A mezzanine floor is a new intermediate level in a building installed between two main floors to create extra space. It usually has a lower ceiling than the floor below and functions almost as a balcony level, providing extra, open space for offices, storage, or retail or industrial facilities. There are no specific uses for a mezzanine floor, but it must be used safely and responsibly.

Technically, a mezzanine platform, like the Cogan Structural Mezzanine Platform, is considered to be part of the primary story below, and not its own floor. It must meet specific size and configuration limits to pass mezzanine floor fire regulations and become a usable space.

Mezzanines typically change how a building is used, as businesses can increase their storage, display spaces, operating areas, or install an office or staff space.

Key Regulatory Bodies and Standards in 2025

Several authorities shape mezzanine design and installation approval in the US. They include:

International Code Council (ICC)

The ICC is a non-governmental membership organization that publishes building codes and standards used across the world. Its mezzanine floor regulations are adopted by most US jurisdictions to ensure they incorporate crucial safety measures, such as having mezzanine safety gates.

National Fire Protection Association (NFPA)

The NFPA works to eliminate the catastrophic effects of fire, which include injury, death, and financial losses, by publishing copyrighted fire safety codes. Businesses use these codes to reduce potential hazards posed by new structural developments.

Americans with Disabilities Act (ADA)

The ADA is a federal civil rights law that prohibits discrimination against disabled individuals in several areas. It requires businesses to provide equitable access to their goods and services, so mezzanines must be reachable and safe. For instance, they must have safety rails.

Local Building Departments

Local building departments enforce regulations brought about by the International Building Code (IBC), giving companies a guide to follow when installing mezzanines, reviewing building plans, and issuing permits for construction.

Core Mezzanine Floor Regulations to Follow

No two mezzanine floors are exactly the same, but they must all meet specific safety requirements. If an inspection finds the plan lacking in any of the following essential regulations, it may be denied.

Height and Area Limitations

Under IBC 505.2 2024, the floor area of a mezzanine cannot exceed one-third of the floor area of the room in which it is located. Although there are exceptions that allow for larger mezzanines in sprinkler zones, these are subject to individual inspections and occupancy limits.

The height above and below the mezzanine floor must also be a minimum of seven feet, and at least one third of its perimeter must be open to the room it overlooks. A fully enclosed mezzanine may be classified as a separate story within the building.

Structural Safety Standards

The Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE 7) doesn’t define mezzanines as structural elements, but it does determine the minimum load that the floor can safely support, depending on its intended use. Some examples include 50 pounds per foot for offices, 125 psf for general storage, and 250 psf for heavy, industrial storage.

Structural safety standards also dictate that a building’s existing floor be evaluated by a structural engineer to assess new load points from mezzanine columns. Any materials involved in mezzanine construction must comply with trade association rules, which include the AISC for steel and ACI for concrete.

Fire Safety and Egress

Per IBC 505.2, the mezzanine counts towards the total fire area of the building, even though it isn’t classed as its own independent floor. There must be a means of egress from the mezzanine to provide safe, continuous access outside in the event of a fire. If the occupant load exceeds ten people, at least two means of egress are required.

The stairways must meet IBC dimension standards, with a minimum width of 36 inches and IBC and NFPA-compliant exit travel distances. You may require smoke detectors, sprinklers, and fire alarms, especially in larger mezzanines. Those that are open for public use may require fire-rated construction, with at least a one-hour resistance rating.

Accessibility Requirements

Whether a mezzanine is designated for public or employee-only use, ADA requires it to be fully accessible. In many cases, this involves installing a ramp, elevator, or wheelchair lift to provide assistance for individuals who cannot otherwise access the level. There may be exceptions if you intend to use the mezzanine for storage or equipment access only.

Per OSHA 1910.29, mezzanines must also meet a very specific set of safety requirements relating to fall protection. These include installing guardrails at 42 inches high, plus midrails to prevent accidents. Sometimes, you may need to make screen or mesh modifications, as well as install hand and stair rail systems for extra support.

Planning Permission and Building Permits

In the US, you don’t need to apply for ‘planning permission’ like in some other countries, but you do need building permits to construct a mezzanine.

When You Need a Permit

Any new mezzanine requires a building permit, even if it is a freestanding level. If the addition of the mezzanine changes the building’s occupancy classification, such as converting a storage space into an office floor, it also requires a change-of-use review.

Separate permits are required for all safety features, plus any changes made to electrical, HVAC, or sprinkler systems. We recommend researching the requirements in your area and using that information to request the relevant permits.

Essential Permit Documentation

Most building departments require you to submit the following when requesting permits:

• Architectural drawings clearly showing the layout, dimensions, and openings of the mezzanine floor
• Structural calculations made by a professional structural engineer
• All fire protection and egress plans

Permits are most commonly delayed when one or more of these essential documents are not submitted on time or submitted incorrectly.

Compliance in Different Building Types

Mezzanines must all meet the same area, structural, safety, and accessibility requirements, but there are certain exceptions depending on their intended use. The existing building type also plays a role in how a mezzanine is classified.

Industrial Buildings

Industrial buildings, such as warehouses, manufacturing plants, and truck terminals, typically install mezzanine floors to store heavy machinery and other equipment. Mezzanine floors for this purpose need reinforced slabs and columns. Any industrial materials used in the creation of the mezzanine must also comply with industry-specific requirements.

Any handling equipment, such as forklift trucks, might need higher headroom clearances, which could influence the height of the mezzanine. A mezzanine can be over seven feet tall, but you should clearly detail the increased headroom in the plans submitted.

Offices and Retail

When constructing a mezzanine for office or retail purposes, the focus is primarily on comfort, accessibility, a look that fits in, and ease of use. Essential systems for customers and employees, including HVAC, lighting, and acoustics, may require modifications, and a trained professional should carry these out.

Even if the loads stored on an office or retail mezzanine floor are lighter than those in an industrial building, they are still subject to legal load requirements, so take that into account when planning. You need to ensure all safety and accessibility measures are fulfilled to protect all the individuals regularly passing through the space.

Residential and Mixed-Use Conversions

It is usually companies that apply for mezzanine approval, but some people install them in residential properties. In this case, the mezzanine must comply with IBC Chapter 12, which covers everything involved with ventilation, heating, and lighting. They must also meet the height, load, and safety requirements.

In mixed-use conversions, separation between dwelling units and mezzanines is often required as an additional safety precaution. Local building departments may have different regulations for such situations, and might also be stricter with residential properties compared to business spaces.

Common Compliance Challenges in 2025

In 2025, rules and regulations remain strict, so it’s crucial that any structural modifications, especially one as ambitious as a mezzanine, meet them. You may not get a building permit due to failure to comply, whether deliberate or accidental. If you make a serious error, criminal charges may arise.

To avoid this, it’s important to be aware of every compliance challenge and how you can successfully meet each one. Below, you’ll find some of the most common compliance challenges and why you must avoid them.

Misclassifying a Mezzanine

As we’ve already covered, mezzanines are typically not classified as separate stories in a building, even if they function as additional floors. This means that even accidentally enclosing too much of the perimeter counts as misclassifying a mezzanine and turning it into an independent level.

If the building department notices this and reclassifies the area as a full story, they will expand the building’s area footprint, posing other issues for the company. That’s why ensuring that all measurements are correct is so important.

Underestimating Accessibility Requirements

No publicly-accessible building can afford to be lax when it comes to ADA. Even mezzanines that are restricted for private employee use, such as in an inplant office, must be safe and completely accessible, unless any exceptions are made. There are plenty of resources online available to help you assess your mezzanine’s ADA compliance during planning.

Misunderstanding Foundations

Even solid foundational materials like concrete might not be suitable for constructing a mezzanine if they are too old or compromised in any way. Many people assume that a building’s existing foundations are fine, then get caught off guard when informed that the slabs cannot support new column loads.

Neglecting Sprinklers

Every public building has a duty to provide up-to-date, working safety features, and for a mezzanine, this always includes sprinklers. It’s possible to construct a larger mezzanine, but this will also require you to extend the sprinkler system, which can be expensive and tricky work.

Jurisdictional Differences

We recommend referring to the local laws of the relevant state and municipality when planning to install a mezzanine. National codes and regulations may not apply everywhere, and certain areas have additional requirements that a building must meet in order to receive the necessary permits.

Steps to Ensure Mezzanine Compliance

There are several steps you can take during the planning process to ensure mezzanine compliance.

Evaluate the Building

Professional contractors should evaluate the building to assess the feasibility of a mezzanine installation. The contractor considers the foundations and electrical systems to see what safety features must be included during the installation.

Hire a Licensed Structural Engineer

On a related note, you should hire a licensed structural engineer with a good understanding of mezzanine construction. They will be able to stamp drawings, perform calculations, and check all of the existing slabs to give you a better idea of what the process will entail.

Develop Clear Plans

In order to apply for building permits, you must submit code-compliant plans. Take time to develop these clearly, covering all of the essential criteria discussed previously. These plans must include things like fire egress, accessibility equipment and avenues, and any necessary mechanical or electrical upgrades.

Submit Early

As soon as all the appropriate plans and other documentation are in order, submit for permits early. This speeds up the process and involves local building authorities early on to catch any issues and prevent expensive surprises later down the line.

Schedule Inspections

Once mezzanine construction has begun, you should still schedule inspections to keep track of progress and ensure no mistakes have been made. Officials from structural, fire, electrical, and accessibility bodies will inspect the mezzanine floor to check that it meets every regulation.

Maintain Compliance

Changes can occur at any time, so even a fully completed mezzanine may be subject to alterations if codes of compliance change in the future. If this happens, schedule a re-evaluation as soon as possible and work with the relevant bodies to make any changes.

Penalties For Non-Compliance

Any sign that a mezzanine does not comply with even one code or requirement may result in:

• A stop-work order to halt construction immediately
• Financial penalties for unpermitted work
• Occupancy restrictions, making it illegal to use the space
• Compensation claims if an accident happens on-site
• Insurance denial due to unpermitted work

Frequently Asked Questions

Do All Mezzanines Need a Building Permit?

Even the smallest mezzanines or those that are freestanding need a building permit and approval under the IBC.

What is the Maximum Size For a Mezzanine?

A mezzanine must generally be one-third of the existing floor room area, though sprinkler systems or special occupancies can increase this.

Does a Mezzanine Always Need to Meet ADA Standards?

In most cases, it’s a good idea to make a mezzanine ADA-compliant to avoid any permit denials, and you must meet these standards if the mezzanine is intended for public use, such as for a retail or office space. However, storage-only mezzanines may be exempt.

Can Mezzanines Become Individual Stories?

Mezzanines are designed to be part of the story below, but only if they are one-third of the floor area limit. Larger mezzanines or those that aren’t open to the space below can be reclassified as independent stories, but this affects the building’s height and area classifications.

Conclusion

Mezzanine floors are a smart way to maximize space and extend a building’s capabilities, but only when built to code. In 2025, complying with the IBC, ICC, ADA, and NFPA is essential. But, with careful planning and clear communication with experienced contractors, you can create a safe and compliant mezzanine. A mezzanine floor can add long-term value to your company and building.