The short answer
60–80mm of clear pocket depth, with the strip set back 30–45mm from the lip.
That is the range that hides the source and still lets the light open up. Anything shallower and you will see the strip itself, or a hard bright line where the beam hits the ceiling.
Why depth matters more than the strip you buy
People spend a long time choosing a strip and almost no time on the pocket. It is the wrong way round. A good strip in a bad cove looks bad. A cove that is too shallow will show:
- The source itself — a visible bright line at the lip, from most seating positions.
- Glare — you catch the strip directly in your eye when you stand up.
- A hotspot — a hard band on the ceiling instead of an even wash.
COB helps with one of these and not the others. A 480 LED/m COB strip gives you a continuous line with no visible dots even at close range, so you will not see diode grain. But it will not save a pocket that is too shallow to hide it.
The numbers
| Measurement | Target | What goes wrong outside it |
|---|---|---|
| Clear pocket depth | 60–80mm | Under 60mm: source visible, glare |
| Strip setback from lip | 30–45mm | Under 30mm: hard line on the ceiling |
| Cove lip below slab | 150–220mm | Under 150mm: hotspot, no throw |
| Gap to ceiling | Leave the throw distance clear | Obstruction: shadow bands |
Clear depth means clear — measured after the aluminium profile is in, not before. A 15mm profile inside a 70mm pocket leaves you 55mm, and you are now under spec.
What about shallow coves?
Sometimes the ceiling height will not give you 60mm. If you are stuck:
- Use a deep profile with an opal diffuser. It will not fix the throw distance, but it will stop you seeing the strip directly.
- Increase the setback as far as the pocket allows. Setback does more work than depth for hiding the source.
- Accept a tighter wash. A shallow cove throws a narrower band of light. It can still look deliberate — it just will not wash the whole ceiling.
What you should not do is fit a strip into a 40mm pocket and hope. You will see it, and by then the plaster is on.
Check this before the carpentry goes up
- Measure the clear depth with the profile in place.
- Sit down in the room. Stand up. Look at the lip from both. If you can see the strip, the pocket is too shallow or the setback is too small.
- Power the strip on the bench and hold it at the intended setback before anything is fixed. Two minutes now, or a rebuilt ceiling later.
The strip
The KAYVA 480 Pro Strip runs 480 LEDs per metre on a COB platform — 50% denser than the 320/m strip most of the market sells. No visible dots, no banding, even in a shallow cove viewed up close. It is Ra95+ with R9 above 50, 12W/m, 24V, 8mm PCB to fit standard aluminium channels.
It is also 20,000 hours at L70 — at eight hours a day, that is nearly seven years — which matters when the strip lives behind plaster.
For driver sizing and power injection on longer runs, use the calculator.