Is there such a thing like a fuse but for moisture? Some material or dye that can be used to know if a wall or floor is starting to accumulate moisture long before mold appears?
We had a moldy, moist wall, which we had to strip of insulation and dry. There were some issues on the roof (broken roof tile, old chimney) that could have been the cause. The wall is on the first floor, and the mold was growing near the ceiling.
The issues have been fixed. It is not clear where the moisture came from other then 'above' so there is no definitive proof that we have fixed our problems.
But we would like to insulate and plaster the wall again, and start using the room again. It would be nice to know sooner rather then later next time there is some problem on the roof.
This is a related question: monitor-in-wall-moisture, but it seems to attract answers involving active, automatic monitoring.