Stain on an old ceiling below a bathroom
The property
A Georgian town house with lime plaster ceilings and a bathroom fitted into a first floor bedroom, its waste running between old joists.
The problem
A brown stain on the dining room ceiling grew after every bath. A plumber had resealed the bath edge, yet the stain returned.
How we found it
We mapped the stain with moisture readings, then ran basin, toilet and bath in turn. Only the draining bath raised the readings, and thermal imaging followed warm water to its waste.
The outcome
The bath panel came off, not the tiles or ceiling, and a loose waste joint sat at the mark. It was remade at a separately quoted price.