I have decided to decommission a basement fireplace, and I'm looking for sage advice so I don't overlook something important. It's a regular woodburning floor-level fireplace that had been converted to a gas fireplace insert some years ago. It vents via the original rooftop stack, and has a garden variety termination cap that doesn't appear to let in the weather. Gas has been disconnected, and my plan now is to frame the opening, board it up, and cover it with Gyproc. The Wise People next door say I should include a vent in the opening to deter moisture, but that's as much as I know. Any advice you can offer will be gratefully received. Thanks.