How to spec a mezzanine before you ask for quotes.

Most "what does a mezzanine cost?" calls go badly because the buyer hasn't yet decided what they want. The fabricator can't quote what isn't specified, so the conversation devolves into ranges. The five questions below are the inputs every fabricator needs before a real number comes back. Answer them and you get a quote you can compare line-for-line.

1. What's the building's clear height?

Mezzanines work because they recover unused cubic. The first question is how much cubic you have to work with. Clear height is the distance from the slab to the lowest overhead obstruction — typically the bottom of joists, a duct run, or a sprinkler main, whichever's lowest in the area where the mezzanine would sit. Not the building's overall height; the actual usable clearance.

Two thresholds matter:

• Under 18 ft clear: single-tier mezzanine only; useful deck height typically 8 – 10 ft above the floor with 8+ ft of clearance below.
• 18 – 24 ft clear: single-tier with comfortable clearance below; some buildings can fit a low second tier.
• 24 ft+ clear: multi-tier becomes feasible.
• 30 ft+ clear: three-tier territory.

2. What's the target deck size?

Approximate, in square feet. Doesn't need to be exact — a 30 ft × 100 ft (3,000 sqft) target is enough. The number drives column count, beam sizing, and whether the project fits in a single-pour concrete deck or needs structural decking. Round numbers are fine; "between 6,000 and 8,000 sqft" is a useful answer if you don't know precisely.

3. What goes on the deck?

This is the load-class question, and it's the single largest cost driver. Three buckets:

• Pallet storage — heaviest pallet weight × pallets per square foot at full density. Most warehouse mezzanines run 125 – 250 psf.
• Work / picking deck — people on the deck plus light product. Usually 100 – 125 psf, but the egress math (number of stairs) gets stricter once occupant load passes the OBC §3.4 threshold.
• Equipment-support — point loads from machinery feet. The number isn't psf; it's a foot pattern from the equipment manufacturer. Always more rigorous than a uniform-load mezzanine. See equipment-support platforms.

Detail on the math is in the load ratings guide.

4. What deck type?

The choice between three options is mostly determined by what goes on it:

• Bar-grate — open mesh. Default for picking decks (sprinkler reach to grade), exterior decks (snow shed), and equipment-support decks where drainage matters.
• B-deck + concrete (composite) — highest capacity per inch of depth. Smooth, supports rolling loads, fire-rated. Default for storage mezzanines.
• Steel plate / heavy plate — for concentrated loads (machinery, dies). Only chosen when the application requires it.

If you don't know, say so — most fabricators (us included) will recommend based on the load case in question 3.

5. How many access points?

Minimum: one stair. Beyond that, two factors trigger more:

• Egress code (OBC §3.4) — past a threshold occupant load, two means of egress are required. Most pick mezzanines and most warehouse mezzanines past 5,000 sqft hit it.
• Pallet drops for replenishment — separate from egress. A pallet drop with a counter-balanced gate lets forklifts feed product onto the deck without compromising the guard. Common on storage mezzanines.

Detail on stair sizing is in mezzanine access stairs.

What you can leave open

Not everything has to be decided at the quote stage:

• Finish — shop primer / galvanized / powder-coat. Easy to swap; the price delta is known.
• Guard infill type — pipe vs square-tube vs mesh. Cost is similar.
• Specific column placement — fabricator usually proposes layout based on the building. Buyer's job is to flag forklift-aisle constraints.

What a complete spec looks like

"6,000 sqft mezzanine, 200 psf, B-deck + 4" concrete, 2 access stairs (1 main + pallet drop), 14 ft clear underneath, building has 24 ft clear height, retail-converted-to-warehouse at [address]." That's a quoteable spec. We can size beams, count columns, run the egress math, and put a fixed-price number in front of you within a few business days of a site measure.