I'm installing an exhaust fan in a thirty year old one storey addition that's built of cinderblocks with stucco on the ouside. I'm looking for an alternative to making a vent hole in the roof and I may have found something.
In the following pictures you are looking at the crawl space under the roof where the roof meets the old wall of the house. In the very corner, there is a "wedge" where there are no cinderblocks and I am wondering what kind of material that is. Is that something that I could drill through to make a 4" opening? (It's in a place that I can't reach by hand but would be able to fish the vent through.)
Many thanks in advance!