Twelve years ago we had a gas log fireplace added to our home. The contractor did an inadequate job on the flashing, so earlier this year I had to replace the flashing, shingles and rotten wood on the chimney. Everything was fine until today, when I noticed what looks like a small amount of water (maybe a quarter of a cup) dripping through the front of the fireplace while it was being used. I'm thinking this may have been condensation; however, it's the first time in twelve years that we've experenced this. What are your thoughts?
It sounds like condensation. Gas, when it combusts, is 80 percent water vapor. If the fireplace brick is cool, you’ll definitely get condensation as a result. However, leaky chimneys aren't uncommon, so an expert might help you put your mind at ease.