More Mysterious Water Damage

Another fun inspection this week. The complaint was that something was ruining the floors in the center of the great room. They had originally suspected that Fluffy the dog was peeing on the rug in the area, at least that was the comment from friends. But the situation continued even after they banned Fluffy from the room.

Now, sometimes, things happen when you aren't home. Like a child lets the dog play where it shouldn't. So I was asked to inspect for dog urine on the rug and floor. Simple, short inspection, or so I thought.

I found no dog urine, or anything that showed up under a UV light. No funny smells, even. No plumbing in the area. No plants or other sources of water in the room. Or maybe I should say common sources of water.

This room had an unvented fireplace. As you all know, when you burn something, the two primary combustion products are carbon dioxide and water. In fact, for every gallon of kerosene you burn, you create about two gallons of water. Burning propane or natural gas does the same thing. (People are actually combustion devices. We breathe in oxygen and eat lots of carbon-based food, and breath out carbon dioxide and water vapor. This "combustion" is how we make heat.)

This particular room also had a very tall domed ceiling. The framing at the peak was not good for getting insulation in the area. So the homeowners ended up with a cold peak (in the winter), where the water vapor from the fireplace condensed. Then it dripped onto the rug. And it allowed mold to grow at the peak. Check out the discoloration in the photo. A close check also showed water tracks down the beams.

In working with the American Lung Association's Healthy House project several years ago, one criteria we established was no unvented fireplaces in the house. I believe Canada and the State of Minnesota both ban them. I've seen lots of other issues from unvented fireplaces, but this is the first time I have seen one affect a floor like this.