My ceilings appear to be drywall but the drywall boards are held together by something. It's not taped off or anything-it looks like the boards are fitted into this extra piece (sort of like a tongue in groove thing) and they go all the way across the ceilings in one direction. It looks really tachy. It reminds me of the ceilings in trailer homes where the stuff is just fitted together. I want to know what these are called and if I can take it out and tape the existing drywall off to give it a smooth appearance...not to mention how I might go about doing that.