ᐅ Mold on the chimney, looking for a solution

Hello,

We built a new house last year and are now spending our first winter in it. We installed a chimney but do not have a fireplace yet; we don’t know when the budget will allow for that.

The problem is that the chimney is located in the utility room and runs through the bathroom up to the attic. Our roof is an unheated roof (cold roof). Between the upper floor ceiling and the chimney, there is mineral wool insulation serving as heat protection. In the bathroom, the chimney was simply plastered and painted. I already measured the chimney temperature with an infrared thermometer, and it only reaches 12 to 15°C (54 to 59°F). Due to the humidity in the bathroom, mold spots are now forming on the chimney below the ceiling.

When we eventually have a fireplace, I think this problem will resolve itself, but until then, we need a temporary solution...

I have considered wrapping the chimney with insulation under the roof and possibly sealing the outlet with a polystyrene board.

Do you think that would help?

It doesn’t matter whether you have a fireplace or not, something like this should never happen. It could be due to excessive humidity in the bathroom or other structural defects.