After a very windy day I found a shiny item in my yard which I'm calling a "roof vent cap". I had a new roof installed about 15 months ago, and I assume this was one I had seen when I was watching the workmen.
I painted it, and with a few tools got on the roof to see where it went. There are 7 or 8 roof vents having interior diameters of about 2". There are 2 roof vents having interior diameters of about 4". Both of these larger vents are within 3 feet of each other. I mounted the just-painted roof vent cap on one of the vents. I'm wondering if both of these larger vents should have such a cap. If not, I'm wondering if I selected the proper vent for my installation.
As near as I can tell, the purpose of the vent cap is to keep rain and perhaps small leaves from going directly into the vent, so I think both vents need a cap. But looking at other houses in the neighborhood, I don't see vent caps on the smaller size vents, and on only some of the larger size vents.
(From where these are located, I believe they vent the water heater, and the furnace - both natural gas burners.)
Enlightenment appreciated on vent usage and recommendations.
Thanks.