Mezzanine decking options.

1. Bar-grate

Open-mesh steel grating, typically 1" × 3/16" cross bars at 4" centres on 1/4" or 3/16" bearing bars. Most common deck on industrial mezzanines that are not pure storage.

Wins for:

• Pick mezzanines and work platforms — sprinkler coverage to grade is preserved through the openings.
• Outdoor decks — snow and meltwater shed through, ice doesn't pond, surface stays slip-resistant when wet.
• Equipment platforms with drainage requirements.
• Multi-tier mezzanines — without bar-grate decks on intermediate levels, the sprinkler system below has to be supplemented with in-rack heads.

Doesn't fit:

• Rolling-load applications (powered pallet jacks, drum carts) — the gaps catch wheels.
• Spaces where small parts could drop through and create a hazard below.
• High-cleanliness food / cannabis facilities — the openings make wash-down impractical.

2. B-deck + concrete (composite)

1.5" or 3" galvanized B-profile steel deck topped with poured concrete (typically 2-3/4" or 4" total slab thickness depending on load). The steel deck is structural during pour; the cured concrete works compositely with it for the final design strength.

Wins for:

• Storage mezzanines — highest capacity per inch of depth, smooth surface, supports rolling loads.
• High-traffic warehousing — the concrete top-coat takes forklift abuse much better than bare steel.
• Fire-rated requirements — composite deck has UL-listed fire ratings that bar-grate doesn't.
• Sound dampening below the deck — concrete mass is significantly quieter than steel.

Doesn't fit:

• Sprinkler-coverage-driven applications without a separate in-rack system.
• Outdoor work — concrete + steel cycle freeze-thaw poorly without specific detailing.
• Quick-install / relocatable mezzanines — concrete pour is a permanent install step.

3. Steel plate

1/4" to 1/2" plate (sometimes thicker) over framing. Heavy, high-capacity, expensive per sqft. Niche choice but the right one for specific applications.

Wins for:

• Concentrated point-loads — machinery feet, dies, equipment mounts, anvils.
• Equipment platforms where the equipment manufacturer specifies a continuous flat surface.
• Wash-down or hose-down applications where bar-grate isn't acceptable but composite isn't fire-rated for the use.

Doesn't fit:

• General storage — overkill for uniform pallet loads; cost is significantly higher than B-deck.
• Drainage applications — flat plate ponds water; needs designed slope or perforations.

4. Resin board / OSB structural panels

Phenolic resin or structural particle board. Light-load only.

Wins for:

• Light-load light-duty mezzanines — typically < 100 psf.
• Budget-constrained installs where the load case doesn't justify steel decking.
• Quick installs / temporary platforms.

Doesn't fit:

• Anything with concentrated loads — point-load rating is significantly lower than steel.
• Wet environments — moisture damage; not a long-term solution.
• Long-life industrial use — replace cycle is shorter than steel options.

Cost ordering (low to high)

1. Resin board — lowest, but limited to light loads.
2. Bar-grate — typical baseline for industrial decks.
3. B-deck + concrete — adds ~$8 – $15/sqft over bar-grate.
4. Heavy steel plate — adds another $10 – $20/sqft over composite.

Detail in the mezzanine cost guide.

Default by application

• Storage mezzanines → B-deck + concrete
• Pick mezzanines / work platforms → bar-grate
• Equipment-support → plate or B-deck (point-load driven)
• Catwalks → bar-grate
• Multi-tier → bar-grate on intermediate, B-deck on top