How do I fill in old downlight holes in a ceiling?

Downlight holes are unusually hard to make invisible. They are large, perfectly circular, in a ceiling where every defect is lit from the side, and there is nothing behind them for filler to grip. The successful method is the plasterboard patch method scaled down: get something solid behind the hole, fit a board patch, and treat the joint as a joint rather than as a filling job.

Safety

What you'll need

• Plasterboard offcut
• A timber batten or a piece of ply, longer than the hole is wide
• Drywall screws
• Scrim tape or a self-adhesive repair patch
• Jointing compound or fine filler
• Taping knives, 100mm and 200mm
• Sanding block and primer

Step by step

1. Isolate the circuit and deal with the fitting and the cable first.Isolate at the consumer unit, remove the fitting, and establish what happens to the cable. It either goes to a new fitting position, or it is disconnected back at its source by an electrician. What it must not do is sit capped inside a sealed ceiling void.
2. Check what else was in the hole.Downlights often have fire hoods, insulation guards or acoustic hoods above them. Those come out with the fitting, and their removal changes the ceiling's fire and insulation performance, which matters if the ceiling separates dwellings or storeys.
3. Tidy the hole.Cut back any torn paper or crumbling edge with a knife so the perimeter is clean and the surrounding board is sound. A slightly larger clean hole is far easier to patch than a ragged one.
4. Fit a backing piece.A batten or a strip of plywood 100mm longer than the hole diameter. Feed it through the hole, hold it across the back, and screw through the ceiling into each end from the front. Two screws either side of the hole. It is now a solid backing that the patch can be fixed to.
5. Cut a plasterboard disc to fit.Same thickness as the ceiling board. Draw round the hole onto the offcut, cut just inside the line, and offer it up — a slightly loose fit is better than one that has to be forced.
6. Screw the disc to the backing piece.Flush with the ceiling surface, not proud. Two screws into the batten, heads just below the paper face.
7. Tape the perimeter.Scrim tape round the circle, or a self-adhesive mesh patch over the whole thing. The tape is the structural part of the repair — this is why filler alone fails.
8. Fill in three thin coats, each wider than the last.First coat just covering the tape, second coat 100mm wider, third coat wider again and very thin, using a broad knife. A circular repair shows if the compound is built up in a mound, so keep taking it wider rather than thicker.
9. Sand flat and check in raking light.A torch held flat against the ceiling shows every ring and hollow. Correct now, because a wall light or afternoon sun will show it later.
10. Prime the repair before painting.Jointing compound is much more absorbent than the ceiling around it. Without a primer the repair dries to a different sheen and every patch shows as a disc — which is the exact failure people blame on the filling.
11. Paint the whole ceiling, not just the patch.Ceilings are lit uniformly and a touched-up circle almost always shows. Cut in and roll the entire ceiling in one go.

Common mistakes

• Stuffing the hole with filler or expanding foam — There is nothing for it to key to. It shrinks, cracks around the circle and eventually falls out, and foam expands and pushes out of the hole.
• Not taping the joint — Board patch to board ceiling is a joint like any other, and untaped joints crack. The ring shows within a year.
• Leaving a capped cable in the void — Concealed connections must remain accessible, and an abandoned cable that is still live at the other end is a hazard for whoever opens that ceiling next.
• Painting the patch and not the ceiling — A disc of fresh paint on an aged ceiling is more visible than the repair was.

Alternatives

• Self-adhesive metal repair patch: A mesh-backed metal disc stuck over the hole and skimmed with compound. Quick, needs no access above, and works acceptably on holes up to about 75mm. Less robust than a board patch and more prone to showing a ring.
• Fit a blanking plate: A ceiling blanking disc that clips into the existing hole. Honest, instantly reversible and much quicker, but visible — reasonable in a utility room or garage, less so in a living room.
• Board over the whole ceiling: Where there are many holes from a removed downlight array, overboarding the ceiling can genuinely be less work than a dozen good patches, and gives a uniform surface.
• Re-use the positions: If new lighting is going in anyway, siting the new fittings in the existing holes avoids the problem completely. Different fittings have different cut-out diameters, so check before committing.

Questions people ask