The stain on the bathroom ceiling above the shower
Most people look at the walls and the grout when a bathroom starts to look tired. The ceiling gets ignored until the paint above the shower starts to flake, a ring of grey spots appears in one corner, or a brown tide mark spreads out from the light fitting.
Why the ceiling suffers first
Warm, wet air rises. During a shower the ceiling sits in the hottest and most humid layer of the room, and in a bathroom with a loft above it, that ceiling is also the coldest surface for the warm air to meet. Condensation forms there before it forms anywhere else.
Reading the mark
A ring of brown or yellow staining around a light fitting or a pipe usually means water from above: a leaking tank, a weeping fitting in the loft, or a roof problem that has found its way down. That is a plumbing or roofing repair first, and repainting before it is fixed only buys a few weeks.
Black or grey speckling, worst in the corners and directly above the shower, is condensation feeding growth on the surface. Wipe it back with a suitable cleaner, let the ceiling dry fully, then repaint with a moisture-resistant finish.
When the board itself is the problem
If the spotting returns within a fortnight of cleaning, if the ceiling feels soft when pressed, or if paint lifts away in sheets with a damp, dark surface underneath, the growth is no longer sitting on the paint. It has reached the paper face of the plasterboard and often the back of it too. No amount of cleaning will fix a board in that state; it has to come down and be replaced. In very humid climates this happens far faster, and readers in the Gulf states who have written to us about it mostly ended up calling Houston mold abatement contractors to take the ceiling out safely, because cutting out contaminated board spreads spores through the house unless the room is sealed first.
Putting it back properly
A replacement ceiling over a shower deserves moisture-resistant board, joints taped and filled cleanly, and two coats of a proper bathroom paint. The paint matters more than it seems: ordinary matt emulsion absorbs moisture and holds it against the plaster, while a kitchen-and-bathroom paint with a sheen sheds it and gives you a surface you can actually clean. Check that the loft above is insulated right up to the edge of the bathroom, because a cold strip along the ceiling line is where condensation gathers first.
The habits that keep it clean
Run the fan through the shower and for a good while after, crack a window if there is one, and wipe the ceiling above the shower once a month with a long-handled mop. A ceiling that dries out within half an hour of every shower stays clean for years.