TECHNIQUE7 MIN · 15 JUN 2026
Cove lighting: the 100mm that decides everything
D
Devang M.
Head of Optical Engineering
Get the setback wrong and you see the strip, the scallops, or nothing at all. A detail drawing you can trace.
Cove lighting seems simple on CAD drawings: a gypsum pelmet with an LED strip tucked inside. Yet on site, 80% of executed coves exhibit ugly light dots, dark corner dead-zones, or harsh cutoff lines on the ceiling.
The Critical 100mm Setback Rule
For a continuous, seamless wash that blends smoothly into the ceiling center, the distance from the top of the upstand lip to the ceiling slab must be at least 100mm to 140mm.
Mounting the LED strip flat against the back wall or at a 45° angled extrusion directs the peak candlepower toward the ceiling center instead of burning out the pelmet drywall.
Recommended Cove DimensioningSPEC SHEET
- Pelmet Lip Height
- 45mm (Hides fixture from human sightlines)
- Vertical Clearance to Ceiling
- 120mm–150mm optimal
- Extrusion Mounting Angle
- 45° tilted towards ceiling center
- LED Density
- ≥ 480 LEDs/m (Dot-free COB continuous phosphor)
Key Engineering Takeaways
- Maintain at least 100mm clearance between the cove lip and finished ceiling.
- Always use continuous COB LED strips inside frosted aluminium profile extrusions.
- Overlap LED strip ends at corners to avoid unsightly dark shadow gaps.