It looks like the previous owners cut the vent stack that goes to the roof and capped it in our mudroom (to relocate the washer and dryer someplace else). I don't think this vent is serving anything at all. Today we had the pleasant surprise to find the cap leaking. We punctured a hole in the cap and an entire bucket of water was in the pipe. The vent stack on the room is not covered and we had a big snow thaw today. Is it possible to cap this? If so how? Also is there some type of professional who does this? Plumber? Roofer?