I tried to search the forum to see if this topic was anywhere else so I apologize if this is a repeat.

I have a new house (1 year old). I was up on the roof yesterday and I noticed that the roof vent (sorry if that is the wrong terminology) is capped. I should also add that I have several "inside" vents throughout the house under the sinks and in the walls.

Is this normal? I seem to remember someone telling me they do this during construction but are supposed to remove the cap. The cap seems to be sealed on there (PVC type pipe).