I have a 100yo Colonial 1 1/2 story. I'm currently remodeling the upstairs, adding a bath, etc. All of the walls (both exterior and interior) and ceilings are tongue and groove (t&g) oak planks. I've pulled the paneling and drop ceilings down to expose the t&g planks. My first plan was to leave the ceilings in t&g and drywall over the exterior walls. I've completely gutted the interior walls and will be building normal 2X4 walls with drywall. However, the t&g isn't in that great of shape, with several coming down with the furring strips. They don't appear to be attached all that great and I would say years ago there was a moisture problem as the boards just feel brittle. Do you think there would be a problem with drywalling over this t&g ceiling (maybe 1/4" or 3/8"?) as long as I can get longer screws up into the rafters? Or should I put furring strips back up and then drywall? Or just gut it all and go straight to the rafters (not excited about that option!). Thanks!