Double Decker & Mezzanine Stall Design — Two Floors of Impact

When a double decker earns its cost, and when it does not

A mezzanine adds roughly 60 to 70 per cent of your ground footprint as usable upper area, at a fraction of what the same square metres would cost as rented floor. That maths works when you need private space: buyer meetings, distributor negotiations, hospitality, or a quiet room for technical discussions that cannot happen at an open counter.

It works less well when your objective is pure footfall. A second storey takes ground-floor area for the staircase and structural columns, and visitors do not climb stairs at a trade show unless they have a reason. If your goal is maximum aisle capture on a small footprint, the money is usually better spent on the ground floor.

The threshold in practice is around 48 to 54 sqm. Below that, the staircase and structure eat too much of the ground plane to justify themselves. Above it, the upper deck starts paying for itself in meetings you could not otherwise have held.

Load engineering and structural approval

A double-decker stand is a temporary building, and organisers treat it as one. Most venues require stamped structural drawings, a load calculation for the upper deck, and sometimes a third-party check before they will permit the build. That approval is not a formality and it is not fast — it is the single most common reason a two-storey stand misses its build-up slot.

We produce the structural package as part of the design, not after it. Deck loading is calculated for occupancy rather than guessed, staircase rise, going and handrail heights are set to the applicable code, and the drawings go to the organiser early enough that a query does not become a crisis.

The practical consequence for you is that a mezzanine needs a longer runway than a single-storey stand of the same size. Ten to twelve weeks is comfortable. Six is possible. Under four, the approval window alone usually rules it out.

• Ceiling height — Most halls need 5.5 m clear to make two usable floors. Below that, the upper deck becomes a crawl space rather than a meeting room.
• Deck loading — Calculated for the number of people and the furniture the upper floor will actually carry, with the margin the venue code requires.
• Staircase compliance — Rise, going, handrail height and landing dimensions to code — the detail organisers check first and reject most often.
• Egress and access — Some venues require a second means of escape from the upper deck above a given occupancy. Better designed in than bolted on.
• Rigging limits — Hanging banners and lighting above a mezzanine are governed by the hall rigging allowance, which varies by venue and sometimes by stand position.

How to plan the two floors

The ground floor is a shop window and the upper floor is an office. Treating them as the same kind of space is the most common design mistake we see. Downstairs wants openness, sightlines into the stand from the aisle, product at eye level and a counter that does not act as a barrier. Upstairs wants enclosure, acoustic separation, comfortable seating and somewhere to put a laptop.

The staircase position decides more than it appears to. Placed at the front, it advertises the upper floor but consumes prime aisle frontage. Placed at the back, it preserves the shop window but visitors need a reason to walk past the products to reach it. We usually favour a side position that keeps the frontage open while remaining visible from at least two approaches.

Under-stair volume is worth designing rather than accepting. It absorbs storage, a services cupboard or a coat area that would otherwise take usable floor.

What a two-storey build costs you in time on site

Double-deckers take longer to build up and longer to dismantle than single-storey stands, and most halls charge for the extra days. A two-storey stand typically needs two to three build-up days against one for a comparable single-storey build, plus the structural inspection some venues carry out before they permit occupancy.

That cost is predictable and should be in the budget from the start. What is not predictable is the cost of discovering on day one of build-up that the structural drawings were never approved. Front-loading the paperwork is the cheapest insurance available on a project of this type.