How to measure a commercial door seal

Getting the measurement right is most of the job. Get it wrong and a custom-made seal arrives that fits nothing, and because it was made to your numbers it can't be returned.

This guide covers commercial equipment: display fridges, prep benches, coolrooms and walk-in freezers. The method is the same for all of them.

What you'll need

A tape measure, preferably metal rather than cloth. A pen and something to write on. A phone with a camera, for the profile step at the end. Ten minutes.

Measure the seal, not the door

This is where most wrong orders come from. You are measuring the seal itself, not the door panel and not the opening.

Take the measurement from the outside edges of the existing seal, where it sits in its groove or dart. If the old seal is missing, measure the groove it sat in, outside edge to outside edge.

If you measure the door instead, you'll be out by the seal width on every side, which on a typical commercial door is 15 to 25mm. Enough to make the seal useless.

Step 1: Open the door fully

You need to see all four sides of the seal at once. On a coolroom door, prop it open. On a display fridge, remove anything in the door shelves that blocks your view of the bottom run.

Step 2: Measure the width

Measure horizontally across the seal, from the outside edge on the left to the outside edge on the right. Take it across the middle of the door rather than at the top or bottom, since seals distort at the corners.

Write it down in millimetres. Not centimetres, not inches. Every supplier in this trade works in millimetres and a decimal in the wrong place is an expensive mistake.

Step 3: Measure the height

Same thing vertically, outside edge to outside edge, taken through the centre of the door.

Step 4: Measure it again

Measure both dimensions a second time before you order. Seals are made to your numbers and can't be sent back, so thirty seconds now is worth it.

If your two measurements disagree by more than 2mm, measure a third time. Doors sag, and a seal that has been on a coolroom for eight years may have stretched or shrunk.

Step 5: Identify the profile

Dimensions alone aren't enough. A seal that's the right size but the wrong profile won't seat in the groove or won't seal against the frame.

The profile is the cross-section shape: the part you'd see if you cut the seal and looked at the cut end. Push-in, dart mount, magnetic, compression, and dozens of variations within each.

Two ways to identify it:

Read the part number. Some seals carry a moulded code on the back or inside the dart. If yours does, that's the fastest answer.

Photograph the cut end. Pull a corner of the seal away from the door and photograph the cross-section straight on, against a plain background, with something for scale like a coin or a ruler. Our identifier will shortlist the closest matches from 216 profiles, and a person here confirms the exact fit before anything is made.

Step 6: Note the corners

Some commercial seals are mitred at the corners, some are moulded as a single continuous piece, and some use corner blocks. Photograph a corner as well as the cross-section, because it changes how the seal is made.

What happens after you order

For custom-made seals we confirm every measurement with you in writing before anything is manufactured. If a measurement looks wrong against the profile you've identified, we'll query it rather than build it.

If we confirmed a part and it turns out to be wrong, that's on us and we'll replace it at no cost, including on custom work.

Still not sure?

Photograph the seal and the door and send it through. Confirming a measurement takes us a couple of minutes and saves you a seal that doesn't fit.