My wife and I just purchased a Philadelphia row house (circa 1886) - A bit of a fixer upper, but sturdy nonetheless. The structure is good, except the pine hardwood floor planks. Clearly they have seen better days. There is noticeable water damage from underneath, huge gaps filled old wood puddy, knots that are beginning to pop out, nails starting to pop back up, etc. Unfortunately, there is no sense in sanding the floors, since many of the planks need to be replaced.
We have a contractor putting up an addition on the back of the house, and he said if we were considering installing new hardwood floors the best way to go would be to install a new subfloor perpendicular over the existing pine planks, followed by the new hardwood floors. He said 1/4" luan would do the trick (followed by some leveling/shimming in low-lying areas). We were originally were going to do this for just the first floor, but since we have some extra money, were planning to do the same for the entire second floor as well.
So here come the questions:
- Is 1/4" luan plywood study enough to use on both levels? Is 1/2" better? OSB or Plywood?
- How would you install the subfloor? Staggered? 1/8" spacing? T/G? Liquid nails followed by screws along the joist lines?
- My biggest question is since I would be increasing the floors 1/4"-1/2" on both levels, how would approach the stairs? There is one set of stairs along the party wall, and adding these new floors would throw off the treads and risers on both sides. Any recommendations on how to approach that issue? The stairs, poles, railings are original to the home, so I would hate to mess up the original design, or compromise it's structural integrity.
Any help in answering this list of questions would be greatly appreciated. Thank you!