We recently purchase a lovely older home. Some of the original hardwood red oak has been removed and replaced. I saved the old wood and would like to use it in the bathroom as a ceiling. It is T&G and in good shape. I am wondering the best way to protect from moister accumulation? There is a fan in the bathroom (vents outside and will likely upgrade), and an existing plaster/older thick drywall ceiling now in place. The bathroom is small about 50 sqft at max. Location Atlanta, GA pretty humid most of the year. BTW it is a full bath.