Wood peckers drilled the siding on this chimney up pretty badly and had a nest inside the chimney box. The old chimney cap was rusted out pretty bad and the water was running off of it and into the wood pecker holes. This easily rotted out the old masonite siding and the osb behind that as you can see in the pics. The house was re-roofed just a couple years ago and they just re-used the existing flashing around the chimney and smeared caulking all up and down it so I had to replace all that as well to make sure there would be no leaks even though I was pretty sure it was just the siding causing the leak.
Instead of patching the siding, I decided it would be best to replace the whole backside and adjoining side from the roof up. The client is having the entire house painted soon. I glued two rubber snakes down to the chimney cap in an effort to prevent the wood peckers from repeating the process in the future.
Wood peckers did cause it natty. There's not much rot in the siding except down at the very bottom. Look at the 3rd pic. There is no rot at all there just the two wood pecker holes. They drilled holes in the siding, entered the chimney box and nested in it. The water then ran in the holes they drilled and did the rot to the osb. I pulled the wood pecker nest out of the chimney box.
Woodpeckers did not cause that damage. The chimney leaked first and then the woodpeckers took advantage of the rot. Look where the damage starts- at the top of the trim where water runs off the chimney top. Masonite-type siding is crap especially when there is no underlayment.
Storm chasers replaced the roof for the first time about 3 years ago and then skipped town so I'm guessing it's about 20 years old?
Nice work Chuck