Design the ultimate mezzanine shed with shed designer.

What is a shed with mezzanine?

A shed with mezzanine is a steel-framed building with a raised internal floor over part of the ground level, leaving the rest of the footprint open to the ridge. The mezzanine adds working or storage area without growing the slab, the wind footprint, or the council setback line. Most Australian mezzanine sheds run a partial floor over 30 to 60 percent of the ground area, leaving a tall open bay for vehicles, machinery or stand-up gear underneath. Picture a workshop with a parts office floating over the back wall, or a rural shed with a hay loft over one bay.

ShedDesigner's mezzanine shed templates use 100% Australian-made BlueScope steel framing, clad in Colorbond®, engineered to AS/NZS 1170.2:2021 wind loading and AS/NZS 1170.1:2002 imposed floor actions for the actual block (Standards Australia). Pick the closest template across the shed designs range, set your span, eave height, mezzanine footprint and access, then submit your design once for free comparable quotes from ShedSafe accredited dealers in your region.

Eave height and headroom under the mezzanine

Mezzanine sheds get undersized on eave height more than any other call.

3.6 metres of eave is the absolute minimum for a usable mezzanine. That gives 2.1 metres clear under the mezzanine slab (the National Construction Code minimum ceiling height for a non-habitable Class 10a space, per Australian Building Codes Board, NCC 2022 Volume Two), about 250 mm of mezzanine floor structure, plus 1.0 metre clear above for crouched storage and the 1.0 metre balustrade on top.

4.2 metres of eave is the working benchmark for a true two-storey effect. That gives 2.4 metres clear under (the NCC minimum for a habitable space if you ever convert), 250 mm of floor structure, and a real 1.6 metres of stand-up storage above. Above 4.5 metres opens the door to a full standing-height upper room with shelf height back up to the ridge.

The gable shape almost always wins at this eave because the ridge sits roughly eave height plus span over two times tan(pitch), so a 12 metre span at 20 degree pitch on a 4.2 metre eave puts the ridge at about 6.4 metres, giving a real second-storey volume under the apex. See gable roof sheds for the roof shape comparison and ridge maths.

Floor live loads under AS/NZS 1170.1

The floor's job is set by the imposed live load it carries. AS/NZS 1170.1:2002 Structural design actions, Part 1: Permanent, imposed and other actions (Standards Australia) sets the load class:

• 1.5 kPa for residential and light domestic storage. Suits a personal mezzanine carrying boxed gear, seasonal items, fishing rods.
• 2.5 kPa for general storage. Suits parts shelves, tool chests, light timber stock, the standard tradie or hobby workshop loft.
• 5.0 kPa for heavy storage and commercial use. Suits drum stock, palletised parts, full bay racking. Anything above 5 kPa moves into commercial mezzanine territory under AS 1657 with stair, balustrade and signage to match.

Higher load means heavier joists, deeper bearers and a more capable column count. Get the use case right at design time, because retrofitting a 1.5 kPa floor to 5 kPa usually means demolishing the original and starting over.

Access, balustrade and the habitable boundary

Three rules drive the build above the slab.

Stair vs retractable ladder. A fixed timber or steel stair sits at 35 to 38 degrees with a 240 mm tread and 190 mm rise, suits any daily-use mezzanine and is the only practical option for an office or sleeping fit-out. A retractable ladder is the right call for an occasional storage loft where slab area matters more than access speed. Both options are designed under the National Construction Code and AS 1657 Fixed platforms, walkways, stairways and ladders for industrial use (Standards Australia).

Balustrade height. A 1.0 metre minimum guard rail sits along every open edge of the mezzanine, with infill no greater than 125 mm and no climbable horizontal members between 150 mm and 760 mm above floor level (NCC Volume One Part D2.16). Drop-through openings need a self-closing gate.

Fire egress and the habitable boundary. A storage mezzanine inside a Class 10a shed (the standard non-habitable structure) has no formal egress requirement beyond the access stair. The moment the mezzanine is used for sleeping or living, the building reclassifies to Class 1a or 1b under the National Construction Code, which triggers smoke alarms, two means of egress, glazing, insulation and ventilation rules. Sleeping above the workshop is a planning conversation, not a free upgrade. For a habitable build see shed homes, which is a different product class.

Best-fit uses

Mezzanines fit a handful of specific buyer briefs.

• Workshop loft. Parts office or assembly area floating over the back of a workshop bay. See workshop sheds for the working-shed framing.
• Man cave bunk and storage. Bunk room or kit storage above a rec room, kept under the Class 10a non-habitable line for casual use. See man caves.
• Garage tool storage. Half-floor mezzanine over the back of a multi-bay garage for seasonal tyres, roof racks, camping gear. See garage with workshop.
• Rural shed hay loft. Loft over one bay of a rural or machinery shed for hay or feed, sized at 5 kPa for stacked bale weight. See hay sheds for the hay-storage angle and the raised-centre option in American barns.

Before you get quotes

A mezzanine is the cheapest second floor you will ever build, but only if the eave, the floor load and the access are right at the slab pour.

100% Australian-made BlueScope steel. Across structural framing and Colorbond® cladding. BlueScope's COLORBOND® steel cladding for sheds and garages carries a warranty of up to 15 years against corrosion to perforation, with the exact period set by location and application (BlueScope, Garages & Sheds Warranty). Check your build on BlueScope's online warranty estimator.

Engineered to your wind region and floor load. Your dealer's engineer signs off the structure to AS/NZS 1170.2:2021 wind loading and the mezzanine to AS/NZS 1170.1:2002 imposed floor actions for the use case you specify.

ShedSafe accredited dealers, no exceptions. Every dealer on ShedDesigner is third-party assessed under the Australian Steel Institute programme, which checks dealer engineering against the National Construction Code and the AS/NZS 1170 series.

One design, multiple quotes. Your mezzanine shed design goes out to dealers covering your region. Every quote prices the same shed, the same eave height, the same floor load class and the same access, so the quotes you get back are directly comparable, down to whether the balustrade gate is included. Browse the broader shed designs range or compare the gable roof shape on gable roof sheds.