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Light cove – dimensions, structure and installation steps

Sizing a light cove: box width, glare shield height and strip placement. Eight installation steps in the right order.

Janne Halttu Janne Halttu · LedStore.fi ·

What a light cove is

A light cove is a box built onto the ceiling surface, closed on three sides with the open side facing upwards. The LED strip sits inside the box in a profile. The light reflects off the ceiling and falls from there into the room as even general lighting.

Curved light slot profile - 55 × 53 mm
Curved light slot profile – 55 × 53 mm. The curved inner surface spreads the light evenly onto the wall and leaves no sharp edge. The driver fits in the same box behind an access hatch.

The difference from a dropped ceiling is size and purpose. A light cove is narrow, built specifically for light – typically 120-250 mm wide. A dropped ceiling is a larger structure that often has other types of lighting too.

The three sizing variables

1. Box width

The width of the opening directly affects how wide an area of ceiling the light spreads over. A box that is too narrow produces a bright band at the edge of the ceiling.

Under 15 m²120-160 mm
Box, vertical80-120 mm
15-30 m² (typical)150-200 mm
Box, vertical100-150 mm
Over 30 m²180-250 mm
Box, vertical120-200 mm
Recommended dimensions by room size

2. Glare shield height

The glare shield is the front edge of the box that stops the strip being seen from normal viewing height. Its height depends on how far the strip is from it: 30-50 mm with the strip 40-60 mm back, 15-25 mm with the strip right behind the lip.

Verified data from a LedStore living room project: in a 295 mm box, a 120 mm glare shield. This worked in a room 260 cm high.

Sit down and check whether you can see the strip directly. If you can – the glare shield is too short. After the plasterboard work it is too late to fix.

3. Strip distance from the glare shield

Practical rule: strip at least 40 mm into the back of the box, i.e. 40 mm from the box’s back wall.

Box width120-200 mm
Box height100-200 mm
Glare shield30-50 mm / 15-25 mm
Strip at the backmin. 40 mm
Framing (min.)48 × 48 mm
Profile type45° angle
Max strip width12 mm
Access hatchRequired!
Light cove construction detail and specifications

Installation steps in order

In this order – no other. Every step done in the wrong order costs later.

Cable into the box before building the frame. At this stage also decide on wired or wireless dimming – the cabling is different.

Timber framing with ceiling brackets, fixed into the ceiling joists. Use a spirit level – straightness decides how straight the line of light is.

Now, before the plasterboard. A hatch at least at each wall. There must be enough space behind the hatch for the driver.

Side wall first, then the top, the glare shield last. The front edge of the glare shield is the most critical detail – the corner must be sharp and straight all the way.

Paint the inside of the box white. The light cove is painted the same colour as the ceiling. The inner surface of the box has a significant effect on how much light is reflected.

Profile inside the box, fixings every 40-50 cm. Always a fixing at a joint. Profile and cover joints must not fall at the same point.

Strip into the profile with adhesive tape, starting from the power feed end. Three-core cable for CCT strips, two-core for single colour.

Driver behind the access hatch or outside the box – never sealed in. Test before fitting the cover. Pair the wireless controller now.

The five most common mistakes

Frequently asked – light cove

How wide should a light cove be?

120-160 mm for a small room, 150-200 mm for a normal one, 180-250 mm for a large or high room.

Can a light cove be made from MDF?

Yes, and it is often neater when the glare shield corner needs to be precise. MDF needs painting depending on humidity conditions.

How long a light cove on one driver?

With a 14.4 W/m strip and a 100 W driver, about 6 m (0.8 safety factor). On runs over 7 m, feed from both ends because of voltage drop.

Does the inside of the box need painting?

Yes, white. The inside of the box reflects light – the lightest surface gives the best result and the most light into the room.

Profiles for this structure

Profiles for light coves

In a light cove the plasterboard box forms the structure and the profile only carries the strip. So the thinnest and cheapest model will do here: a 9 mm low surface profile in the bottom of the box. It hides nothing, so the bottom and edges of the box must be finished. Plaster-in profiles, on the other hand, form a finished light edge themselves.

Needs a box 1 / 5
Low surface profile

Profile-SURFACE-2m · white, black or brushed

The most widely used profile in indirect dropped ceilings: 48 × 48 mm battens and plasterboard, profile in the bottom or edge of the box. Only 9 mm high and €35 – the cheapest way to get the strip into a profile. Requires the bottom and edges of the box to be finished, because the profile does not hide the structure. Max 14.4 W/m strip; 17 W/m needs more cooling.
Dimensions 18 × 9 mm · 2 m
Max strip 8 mm
Installation Surface, clip mounting
35 € LedStore →
Seamless wall 1 / 4
Plaster-in wall profile

Profile-INDIRECT-KIPSI-2m

Screwed to the wall through the base, skimmed over when the wall is skimmed and painted the wall colour – the profile becomes a seamless part of the wall, only the light slot is visible. Light upward. Takes a 15 mm strip; a dot-free COB strip is recommended.
Dimensions 82 mm high · 33 mm from the wall
Max strip 15 mm
Installation Screwed + skimmed over
60 € LedStore →
Plastered out of sight 1 / 5
LOW Z INDIRECT

Profile-INDIRECT-LOW-Z-3m

The lowest plaster-in solution: minimum batten depth only 17 mm, and the light surface sits 7.5 mm from the finished ceiling. Sized to go alongside a 22 mm timber batten or a 20 mm steel hat channel – keep the battens 14.5 mm off the wall, so a 12.5 mm plasterboard comes out flush. The plaster-in flange hides the profile in the ceiling board.
Dimensions 3000×38×20 mm
Max strip 10 mm
Installation Plaster-in, in the corner
50 € LedStore →
Softest light edge 1 / 3
Recessed in the ceiling, curved light slot

Profile-INDIRECT-curve-W-3m

Screwed to the frame and covered with 13 mm plasterboard – the light emerges from the curved profile surface painted white. The curved inner part diffuses the light softly and removes the hard light edge from the box opening. Recommended strip 14.4 W/m.
Dimensions 78 mm wide · 3 m
Max strip 13 mm
Installation Recessed into the frame
123 € LedStore →
Lip edge 1 / 5
Plasterboard edge

Profile-drywall-edge-W-2m

Fitted to the edge of the plasterboard on the lip of a dropped ceiling or light cove. The 30 mm front strip hides the LED strip, mounting recess 13 × 8 mm. Gives a finished edge without a separate trim.
Dimensions 2000×30×40 mm
Max strip 12 mm
Installation On the board edge
50 € LedStore →

Prices include Finnish VAT of 25.5 % and are current LedStore.fi prices. Profiles include an opal cover and end caps; the LED strip is ordered separately.

Completed projects

Light cove toteutettuna

Plasterboard bulkhead katon reunassa – kuusi toteutettua valokatkoa eri tiloissa.

1 / 5

Photos: completed LedStore.fi projects.

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