Minimum Cove Depth for COB LED Strip

That “perfect line of light” you see in renovation photos usually fails for one simple reason: the cove is too shallow, so you end up with visible dots, a bright stripe on the wall, or glare when you sit on the sofa.

COB LED strip helps a lot because it’s a continuous phosphor surface (not spaced LEDs), but it is not magic. You still need enough cove depth and the right placement to let the light blend and wash smoothly.

What we mean by cove depth (and why it matters)

Cove depth is the vertical distance from the LED strip up to the lip that hides it from view, or more practically, the “pocket height” that controls two things: whether you can see the light source, and how much room the light has to spread before it hits the wall or ceiling.

If the cove is shallow, the strip sits too close to the edge. Your eye catches the bright source, and the first few inches of wall get over-lit. If the cove is deeper, the source is hidden at normal viewing angles and the wash looks calm and even.

In most homes (including common Singapore-style layouts with living room seating facing the TV wall), the biggest issue isn’t “brightness.” It’s comfort. A shallow cove can create a sharp line of light or direct glare that makes the room feel harsher than it should.

The minimum cove depth for COB LED strip (practical numbers)

Here’s the most useful way to think about the minimum cove depth for COB LED strip: there’s a minimum for hiding the source, and there’s a minimum for making the wall wash look smooth. Often those are different.

For most residential interiors, a realistic minimum depth starts around 2 inches (50 mm) if your only goal is to tuck the strip out of direct sight. That assumes the strip is set back from the edge a bit, and you don’t have low viewing angles from a bed or sofa.

If you want a noticeably cleaner “floating ceiling” look with fewer bright edges and a softer wash, 3 to 4 inches (75 to 100 mm) is where coves start to behave predictably. This range gives the light room to spread and makes placement less fussy.

If you’re doing a premium wall-wash effect, or you know the cove will be viewed from many angles (open-plan living, low seating, people walking close to the wall), 4 to 6 inches (100 to 150 mm) gives you the most forgiving results.

You can go deeper, but past that you’re usually trading ceiling height and carpentry cost for relatively small visual gains, unless you’re chasing a very uniform wash on a tall feature wall.

Depth alone isn’t enough: setback controls glare

A shallow cove can still look good if the strip is placed far enough back from the edge. Think of depth and setback as a pair.

Depth is the vertical “hiding height.” Setback is the horizontal distance from the lip to where the COB strip sits.

If you keep depth minimal (around 2 inches), you generally need a larger setback so the lip blocks the line of sight. With a deeper cove (around 4 inches), you can place the strip closer to the edge and still avoid glare.

This is why two coves with the same depth can look totally different. If the strip is installed right at the edge of a shallow cove, you’ll see the source. If it’s set back, your eye sees the wash instead.

What changes the minimum cove depth in real projects

COB strips are more forgiving than older “dot” strips, but there are still a few variables that push your minimum up or down.

1) What surface you’re washing: wall vs ceiling

If your strip is aimed to wash a wall, any unevenness shows more because the wall is in your direct field of view. You usually need a bit more depth (or more setback) to avoid a bright band near the top.

If your strip is aimed upward to bounce off the ceiling, you can often get away with slightly less depth because the ceiling bounce naturally softens the light. The trade-off is you may get less drama on feature walls, and the room can feel flatter if that’s the only layer of lighting.

2) Brightness and wattage per meter

More power per meter means a brighter source. A brighter source is easier to see, and it exaggerates hotspots on nearby surfaces.

If you’re using a high-output COB strip for a large living room, the “minimum” depth to hide glare tends to creep upward. In those cases, 3 to 4 inches is usually safer than trying to make 2 inches work.

3) Color temperature and CRI expectations

Warm white (around 2700K to 3000K) tends to feel more forgiving to the eye, even if the cove is a bit shallow. Neutral or cool white can make any harshness more obvious.

High-CRI strips are worth it for accurate finishes and skin tones, but they can also reveal surface texture more clearly. If your wall has a lot of texture, a shallow, intense wash can highlight every bump. More depth and a softer bounce helps.

4) Viewing angles in a typical home

This is the one people miss during renovation planning.

In a bedroom, you often view the cove while lying down. That’s a low angle, and glare becomes much more likely. If the cove is near the headboard wall or within your line of sight from the bed, aim for 3 to 4 inches minimum, sometimes more depending on setback.

In a living room, if your sofa is close to the cove wall or you have a low TV console, you’ll see up into the cove more easily. Again, 3 inches-plus buys you comfort.

A simple way to sanity-check your cove design

Before the carpentry is finalized, do a quick “sightline test” on the plan.

Imagine an eye level of about 40 inches (seated) and 60 inches (standing). Draw a straight line from that point toward the cove edge. If that line can “see” the LED position, you’ll likely get glare.

If you can’t do drawings, do it physically: mark the proposed cove edge with painter’s tape, then hold a flashlight or phone light where the strip would sit. Walk around and sit where you’ll actually use the room. If you see the source, the cove needs more depth, more setback, or a better shielding lip.

Common depth mistakes (and how to avoid them)

The first mistake is building the cove depth around what looks slim on paper instead of what hides the source in real life. A 2-inch cove sounds neat and minimal. It also has a high chance of glare if the strip is near the edge.

The second mistake is forgetting the aluminum profile and diffuser (if you’re using one). Even with COB, a profile helps with heat management, straightness, and long-term reliability. But it also has its own height. If your cove depth is barely enough for the profile and wiring, you may be forced to place the strip in a glare-prone position.

The third mistake is over-lighting the cove because “brighter is better.” Cove lighting is usually a layer. If it’s doing all the work of downlights and task lighting, you’ll crank it up, and any shallow-cove flaws get amplified. Better to plan the lighting as a system: cove for ambience, downlights for general, and task lights where you need them.

What we recommend for typical renovation scenarios

If you want the most reliable outcome with minimal back-and-forth during installation, plan around 3 to 4 inches of depth for COB strip coves. It’s the sweet spot where you can still keep ceilings feeling high, but you’re not fighting glare.

If your false ceiling is tight, you can target 2 inches as an absolute minimum, but treat it like a “precision install.” You’ll need a good setback, consistent mounting, and careful testing from real viewing angles.

If you’re planning a feature wall wash (TV wall, fluted panels, stone veneer), consider 4 inches or more. Feature materials are expensive, and a harsh light band at the top can cheapen the whole look.

Don’t forget the electronics: drivers and dimming affect comfort

Cove lighting looks best when it dims smoothly and doesn’t flicker. That comes down to using a compatible LED driver and, if you’re doing smart control, a controller that matches the strip voltage and load.

A shallow cove that’s slightly glary becomes much more tolerable when you can dim it to the right evening level. A deep cove with the wrong driver can still disappoint if it flickers on low dim or shifts color.

If you’re planning COB strips across multiple rooms, it also helps to standardize your voltage (often 24V for longer runs) and size drivers with headroom. That reduces voltage drop and keeps brightness consistent.

If you want a simple shopping path for COB strips, drivers, and controllers that are matched for residential installs, we stock the common configurations locally at THE LIGHTING GALLERY.

The trade-off: deeper coves vs ceiling height and maintenance

Yes, deeper coves tend to look better. But in real homes, you’re balancing depth against ceiling height, air-con trunking, curtain pelmets, and access for maintenance.

A deeper pocket can be slightly harder to reach for cleaning or future replacement, especially if the strip is mounted high and far back. If you expect changes later (new curtain track, repainting, swapping controllers), keep the design serviceable. Sometimes 3 inches with good placement is smarter than 6 inches that’s a pain to access.

The goal isn’t to build the deepest cove possible. It’s to build a cove that looks calm at night, hides the source from where you live, and gives you enough flexibility to mount the strip cleanly.

If you’re stuck between “minimum depth” and “best result,” choose the option that reduces glare first. A softer, glare-free cove at a slightly lower brightness will feel more premium every single day than a super-bright cove that you avoid turning on.