How to Extend an Existing Mezzanine as Your Business Grows

Sooner or later, many growing businesses find their mezzanine is full. The usual options are to look for a bigger building or to extend an existing mezzanine so it covers more of the floor you already have. Extending is often the more practical choice, but only if the original structure, the building and the approvals all allow it.

This article covers adding bays to an existing mezzanine, how to check whether it can be done, and what to think about if you move to new premises. It is written for owners and operations managers who want a clear starting point. By Mark Slocum, Founder and Lead Consultant at Factory Mezzanine Floors (FMF).

When It Makes Sense to Extend an Existing Mezzanine

Extension suits businesses that like their site but have outgrown their floor space. The building shell, location and services stay the same. You add floor area rather than starting again.

It tends to make sense when:

• You have unused floor and height below the roof where the platform could continue
• The original mezzanine was designed with expansion in mind
• Your growth is steady and you can plan in stages
• Moving would disrupt staff, customers or equipment

It is less straightforward when the existing structure has no spare capacity, the building cannot take more load, or the extra area triggers a different approval pathway. A site assessment will tell you which applies.

Check What You Already Have

Before you sketch an extension, gather the facts about the existing mezzanine.

• Drawings and certification. Find the original engineering drawings, load calculations and certification pack.
• Design loads. Know what loads the floor was designed for and what is currently on it.
• Footings and slab. Confirm what the columns sit on and whether the slab can take more point loads.
• Column grid. Identify where new bays can join without clashing with racking, machinery or doors.
• Clearances. Check headroom above and below, including lighting, sprinklers and services.

If drawings are missing, expect your engineer to need extra investigation.

How Extending a Mezzanine Works in Practice

Adding bays

An extension generally adds new structural bays to the existing platform. These need columns, beams and decking that tie in with the original, and the combined structure has to work as one engineered system. Your engineer will confirm whether the existing steelwork can be joined to, or whether the new section should stand independently.

Building a second platform

Sometimes a second, separate mezzanine suits better than a continuation. Mike Carney Toyota needed more spare parts storage inside a live workshop, and FMF delivered a second mezzanine on a 300 square metre footprint. The project needed certification and added approvals, and Christmas shutdowns slowed progress. Read the full story on the Mike Carney Toyota Part 2 project page.

Staging the work

You do not have to build everything at once. Label Power, Australia's largest label manufacturer, expanded through multiple mezzanines over time under a staged expansion plan, integrated with the arrival of a new large-scale printing machine. See the Label Power project page for details.

Engineering Considerations

An extension adds load and changes how the structure behaves, so engineering comes first, not last.

Your engineer will look at:

• Whether the existing columns, beams and footings can support the extension
• Loads for the new area, whether storage, offices or equipment
• Connection details between old and new sections
• Stair, gate and handrail arrangements, including egress from the larger platform
• Lighting, services and any fire systems that need to extend

FMF designs are engineered for your site, loads and operations, and every mezzanine, whatever its use, must be structurally certified. If a goods lift would help with a larger platform, see our mezzanine goods lifts.

Approvals When You Add Floor Area

Extending a mezzanine adds floor area, which is what regulators care about. The rules vary by state, and your certifier or building surveyor makes the final call.

• National: Under NCC 2022 Volume One, clause C2D3(4), a mezzanine is regarded as a storey for rise in storeys if its floor area is more than 200 m² or more than one-third of the floor area of the room, whichever is the lesser. Two or more mezzanines at or near the same level are aggregated, so an extension can push a mezzanine over the threshold. (NCC 2022 Volume One, Part C2)
• Queensland: Building work needs a building development approval unless it is accepted development under the Building Regulation 2021, and a certificate of occupancy is required before the building is used after the work. (Business Queensland and certificate of occupancy)
• New South Wales: The Standard Instrument LEP definition of gross floor area includes the area of a mezzanine. Because a mezzanine adds gross floor area, it generally cannot be done as exempt development or as a Part 5 internal-alteration complying development certificate. It is assessed either as complying development under the Part 5A additions standards, if the land and zone are eligible, or through a development application to council. (NSW Planning pocket guide)
• Victoria: All building work requires a building permit unless an exemption applies (Building and Plumbing Commission), and you appoint a registered building surveyor to apply for it (Building and Plumbing Commission).

Confirm your pathway with a certifier early. Our council approval guidance can help you work out what applies to your site.

If You're Moving: Plan the Mezzanine for the New Site

Sometimes extending is not possible, or your business is moving anyway. A relocation brings its own mezzanine questions, because a mezzanine is an engineered structure designed around a specific building and a new site brings new loads, access and approvals.

Two FMF projects show this:

• Bailey Print Group relocated to a new factory and needed a large enclosed production office with clear sightlines. FMF built a tall 400 m² mezzanine with glass walls, dual staircases and motorised pallet gates. See the Bailey Print Group project page.
• Bar Fridges Australia relocated quickly to a new Ballarat facility with a large open footprint but not enough usable storage area for its stock. See the Bar Fridges Australia project page.

If you are weighing up a move, compare the full cost of relocating against the cost of extending where you are, and remember a new site brings its own approvals.

A Practical Planning Checklist

• Locate the original drawings, loads and certification for the existing mezzanine.
• Define how much extra area you need now and in three to five years.
• Ask an engineer whether the existing structure and slab can support an extension.
• Map access, stairs, gates and egress for the larger platform.
• Confirm the approval pathway with your certifier or building surveyor.
• Decide whether to extend in one stage or several.
• If moving, plan the mezzanine for the new site before you sign the lease.

Our free mezzanine floor planning checklist covers the wider planning questions.

Plan Your Mezzanine With FMF

If you want to plan a mezzanine for future expansion or for a new site, call 1300 998 883 or request a free quote. Our first discussions and site visits are obligation-free.

FAQs

Can any mezzanine be extended?

Not automatically. It depends on the existing structure, footings, the building and the approval pathway. An engineer needs to assess the original design before extending.

Do I need new approvals to extend an existing mezzanine?

Often yes, because an extension adds floor area. The requirements differ by state and by the size and nature of the work, so your certifier or building surveyor will confirm what applies.

Can the original design allow for future expansion?

Yes. We can design a mezzanine for future expansion, and planning for it at the start generally makes later additions simpler.