Nice, that home looks like you earned a nice wage for your hard work. I usually stay off the wood roofs in fear of slipping or me damaging, what are your secrets?, what shoes you wearing. I hope you know the old man was me kidding, you probably woop most younger inspectors.
No secrets just two words cautious and careful I wear rubber sole shoes
What is the PH of your water supply? The odor may be a chemical reaction between the water and stone. If your water is higher or lower than a 7, this may be the culprit.