I am about to install a hardwood floor into a room in my 1905 farmhouse. The subfloor is 8-12" wide 1" thick planks. The floor I am installing is 2-1/4" prefinished solid hickory tongue and groove.
Reading books and web how-tos on this a few have mentioned that there should be a layer of "Construction Paper" between the subfloor and the floor strips. The accompanying pictures show stuff that is brown, paperlike and comes in 3' or 4' rolls. I have never seen the like for sale in my local home improvement stores.
What is this "Construction paper"? and is it really necessary?