waterproofing

It's not complicated enough that a novice DIYer has to learn the skills, tools, techniques and best practices for what is otherwise a simple job in the hands of the All Knowing. He also has to learn the Babylonian nomenclature for the stuff he needs to do it. For instance, last year I was derailed for two days trying to find the name for a particular type of moulding I needed for the wainscot in my master bedroom renovation.

I had the same problem trying to find the rooftop vent "thingie" for my bathroom fan. The not-too-bright helper for the GC I'd hired to rough-in my upstairs bathroom a few years ago had installed the wrong kind. It's not called a "fan vent". It's called an "exhaust roof cap". It took me an hour in Google just to find the correct name for it.

Igor may have known what it was called but not what it was for. It's intended for a pitched roof. I have a flat roof. As a result, this was the source of three years of water leaks which were damaging my pristine walls and kept me scratchin' and fixin' until I sussed out what the problem was. After finding the product (a Broan #636 roof cap) it took three seconds with the literature to find "DO NOT INSTALL ON A FLAT ROOF".

On a pitched roof, the exhaust port (on the right) is oriented "downhill" (I'm sure there's a construction term reserved for that). What happens on a flat roof is that any storm force wind blowing into that port will pop open the lightweight damper and the rain will pour in.