I’m in the process of renovating part of my basement. It’s a capecod house where the brick runs all the way to the top of the first story. 1″ furring strips are attached to the inside of the exterior walls for the first story followed by a plasterboard and then a layer of drywall (each approx. 1/2″). When insulating the knee wall on the second story, I noticed that this 1/2″ to 1″ gap is generally accessible all the way to the basement. When I was insulating the kneewall, I started to seal this gap for fire safety, but began to think that the reason the wood was in generally great condition for being 60 years old is partly due to the presence of these gaps.

I would like to improve the safety of the house and am inclined to fireblock in the basement and the knee wall. However, I also wonder if this would be bad regarding moisture as I would be getting ventilation with the cool humid air being pulled up into the attic and eaves.