How do I fit a plaster ceiling rose?

A ceiling rose is a heavy decorative plaster moulding with a hole in the middle. Two things go wrong: it is positioned by measuring rather than by looking, so it sits visibly off-centre in a room that is not square; and it is fixed with adhesive alone, so it eventually parts company with the ceiling. Neither is difficult to avoid.

Safety

What you'll need

• Plaster ceiling rose
• Coving or cornice adhesive
• Screws long enough to reach the joists, and cup washers
• Joist detector
• A hole saw or a padsaw
• Filling knife and fine filler
• Ladder or platform, and a second pair of hands

Step by step

1. Isolate the lighting circuit and take the existing fitting down.At the consumer unit, not at the switch. Leave the electrical rose or the cable in place and note how the fitting is supported.
2. Find the centre by eye as well as by tape.Measure the room's centre, mark it, then stand in the doorway and look. In a room with a chimney breast, a bay or a non-square plan, the geometric centre often looks wrong. The eye wins — adjust and re-mark.
3. Find the joists around the centre point.Detector plus pilot holes. You need at least two fixing points that reach timber, and the rose has to be positioned so those points fall within its diameter but away from its most delicate detail.
4. Drill the rose for the cable before you lift it.Mark the centre on the back, and cut a hole large enough for the cable and any fixing hardware to pass through comfortably. Support the rose fully on a flat surface while you cut, and cut from the face side to avoid breaking out the detail.
5. Dry-fit it.Offer it up with the cable through the hole, check the position from the doorway, and mark round the perimeter in pencil. Mark your fixing points on the ceiling through the rose.
6. Prepare both surfaces.Scrape the paint off the ceiling inside the pencil line so the adhesive bonds to plaster, and dust off the back of the rose. Adhesive stuck to emulsion is the reason roses fall off.
7. Apply adhesive and set it in place.A generous even coat over the back of the rose, avoiding the very edge so it does not squeeze out everywhere. Lift it into position — this is a two-person job for anything large — and press it home.
8. Screw through into the joists immediately.Countersunk screws with the heads set below the surface, through the rose into timber, at the points you marked. These carry the weight while the adhesive sets and they stay in permanently.
9. Clean the squeeze-out at once.A damp sponge round the perimeter before the adhesive sets. Once it hardens on a moulded surface it has to be picked out of the detail.
10. Fill the screw heads and the perimeter joint.Fine filler over each screw and a neat line of the same adhesive round the edge, smoothed with a wet finger, so the rose reads as part of the ceiling rather than as something stuck on it.
11. Refit the light.The fitting hangs from the ceiling structure — from the existing electrical rose or a suitable fixing into a joist or noggin — passing through the decorative rose. Nothing heavy should be supported by the plaster moulding itself.

Tips

• Buy the rose and the coving as a matching set if you are fitting both; profiles and periods clash badly when mixed.
• Scale matters more than detail. A rose that is too small for the room looks like an afterthought, and one that is too large dominates. Cut a paper circle to the diameter and stick it up before buying.
• If you are fitting a heavy chandelier, sort out the structural support first — a noggin fixed between the joists at that point — and design the rose position around it.
• Where a rose is going onto a lath and plaster ceiling, every fixing must reach a joist. The laths will not hold it and the adhesive alone will not either.

Common mistakes

• Fixing with adhesive alone — A plaster rose is heavy and hangs in tension against gravity. Adhesive holds it while it sets; screws into the joists hold it for the next fifty years.
• Cutting the cable hole after fixing it up — Cutting overhead into a fixed moulding cracks it, and there is no way to support it from behind.
• Centring it purely by measurement — Rooms are rarely symmetrical, and a rose that is mathematically central over an asymmetric room reads as a mistake.
• Hanging the light from the moulding — Plaster is not a structural fixing. The load has to reach timber.

Questions people ask