Q: I have a 13-year-old gas/forced hot air system with a humidifier. Over the years, I noticed that the interior of the ductwork is lined with some sort of fiberboard insulation. I’m convinced this insulation could be a place for mold to grow. Do you have any thoughts or experience with this?
A: My response is based on the flexible duct in my basement. When I disconnected the duct to expose the interior, it was bone dry, even though I use the furnace’s humidifier. In your case, I don’t think mold would be an issue since you seem to maintain the ducts. So use your humidifier, but be vigilant.
Q: My brother renovated my second-floor bathroom. Now, every time I do a load of wash, when the first-floor washer is filling up, a lot of water comes out of my shower faucet.
A: I am assuming your brother is not a professional plumber. But you may well need a plumber.
I am not a plumber. Still, I have a couple ideas. If water were coming up through the shower drain as the washer drained, the cause might be a partial clog in the main drain. Your problem seems to be some sort of crossed supply-line connection that carries water to both shower and washer, instead of one at a time.
Have your brother check the supply-line connections first.
Then call a plumber.