Maybe you already have wood floors and they just need some help. Or perhaps you just uncovered old floorboards underneath several other floors and you wonder if they could be turned into a beautiful floor.
If your house is old, you may have uncovered the subfloor. Today, we use plywood for our subflooring, but in the past in my region they used old-growth pine and fir.
Is there anything wrong with using this as your finished floor? Not necessarily. Just keep these things in mind: Gaps between boards will be open to the space or joist bay below. Subfloor helps to stiffen the finish floors above, so make sure the floor is not too thin to support daily use.
Check how much repair will be needed, too. To make invisible repairs, you'll need to add in salvaged boards. This is labor intensive, and you'll need to source the wood. After repairs, you'll sand, but if glue or paint is built up on the floor, this could use up more sandpaper and time than it's worth.