The prior owners of my home built a screen porch several years ago, and used western cedar on the walls, but interior sheetrock with sprayed popcorn texture on the ceiling. Over the years the outdoor elements have caused the popcorn texture to begin dropping from ceiling, and creating quite a mess.
I plan to put T1-11 or bead board, stained or painted on ceiling to correct this problem. My question is should I remove the sheetrock ceiling, or just go over it with wood?????
If you are in a climate that is often wet/humid I would get rid of the drywall. Replace it with a PVC bead board like Veranda(i think you can find their product by searching 'plastpro'), or one from a siding mfg. like Royal Mouldings. Just make sure it is stiff enough for horizontal installation.