Display Deck Drip: Running a Pad and a Drain Tray Together

The fish counter at a supermarket runs four decks at 1 °C, sloped about eight degrees toward a drain channel at the back. Three of them stay dry all day. The fourth, the one nearest the door, has a pad that goes see-through by noon and a puddle along the front lip that nobody can explain.

Sloped display decks are the one place where a pad and a drain belong together, and where getting the geometry wrong produces a pad that fails without ever being full.

Why the slope changes everything

On a level tray, drip stays where it lands and the pad takes it. On an eight-degree slope, drip runs downhill continuously. A sheet covers 100 percent of the deck floor, but the water spends only seconds on any given square centimetre before moving on. What the sheet catches is what it can take during that transit, which is a rate question, not a capacity question.

This is why a 500 gsm sheet sometimes performs worse than a 250 gsm one on a sloped deck: the thicker sheet absorbs more slowly at the face, so more of the moving film reaches the channel. Rate beats capacity whenever gravity is doing the work.

The drain has to stay open

The classic failure is a pad laid over the drain slot. It looks tidy, it covers the whole deck, and it blocks the only exit. Water pools behind the pad, the pad lifts, product sits in liquid at the front edge, and the deck overflows onto the floor at 11:00 during service.

Cut the sheet to stop 20 mm short of the channel. The 20 mm gap is not a defect; it is the drain. If the deck has a central channel, use two sheets rather than one with a slot cut in it — a cut edge wicks and the slot fills with fibre within a day.

Layout that holds for a full trading day

• Pad 250-300 gsm, cut to the deck floor minus 20 mm at the drain edge.
• Product on a raised grid where possible, so contact with the sheet is intermittent rather than continuous.
• Change at 12:00 and again at close for a full day; the door-adjacent deck may need a third.
• Wipe the channel at every change — the pad cannot clean what has already passed it.

A counter-intuitive result from a store trial

Two stores ran a month-long comparison. Store A used pads alone with the drain taped shut to stop smells. Store B used pads plus an open drain and a daily channel flush. Store B used 30 percent more water and 20 percent fewer pads, and its case temperature ran 0.4 °C cooler because the air could move through the open channel.

Taping the drain is the most common fix in stores with an odour complaint, and it always trades a small smell problem for a large wet-product problem. If the channel smells, the channel needs a flush schedule, not a lid.

What to check at handover

Three things at the end of a trading day: the pad immediately under the thickest product, the front lip of the deck, and the channel mouth. If the pad is spent but the lip is dry, the layout is right and the sheet is undersized. If the pad is intact and the lip is wet, water is bypassing the sheet and the geometry needs looking at, not the grammage.

Service-time top-ups

A display deck is not a static system. Product is added, moved and sold all day, and every new tray landed on a spent sheet pushes the wet patch somewhere else. The midday change is not just about capacity: it is the moment when you reset the layout, put the sheet back under the product rather than under the gap where something used to be, and check that nothing has slid against the drain edge.

Ten minutes at 12:00 will do more for a fish counter than any change of pad specification, and it is the one task that reliably gets dropped when the shop is busy.

Sheet formats that suit a sloped deck, including half-length cuts for a central channel, are listed with the counter and display pads, and cutting to length beats folding a full sheet around the drain.

Display drip is a plumbing problem with an absorbent component. Solve the plumbing first, and the pad becomes a cheap backstop instead of an expensive disappointment.