Several of the rooms in the house are covered with tongue and groove 4" cedar, installed at a 45 degree angle. Probably very expensive when a previous owner had it installed, but it is not my cup of tea, and I want to cover it up.

I was thinking of using 1/4" sheet rock. Any other suggestions? The ext. walls were insulated in the 90s so there is no other benefit to removing the cedar.

Probably no way of getting around removing all the trim in the room to do this, right?