Thanks for the tip. Would a leak like that cause the entire floor to cup? Could it be possible that the floor was poorly installation? Honestly I don't remember when the cupping started to occur. Anyhow, a home inspector is a good place to start. I appreciate your input!

:) Yes, the exterior is ugly. I'll grant you that. We suffered from previous owners (circa late 1970s is my guess) and their desire to do asbestos tiles siding over the original. While I'd love to tear it off and put up new siding, there's not much reason to other than curb appeal, and we'd rather put our money into the interior and living spaces. We do have plans to paint, replace gutters, and we are replacing attic windows. Eventually we will replace all windows. Attic was replaced in 2010. Sure, the exterior isn't flashy and lovely and definitely won't win awards, but it is what is and it's what we've got. Maybe historic home isn't the best term, but it would be the terminology used in our town to describe our neighborhood and our house, for better or for worse. It's really what's inside in the interior that we like, along with the location and overall features of the home. Our home has all original oak floors, quarter sawn oak pocket doors and trim and 5 panel doors all original to the house, a huge chapel bench in the foyer that is built in, and none of it has been painted. Sure, it's not a grand historical home, but those are rare in general, and there's probably only 3 or 4 like that in our town. What is rare is the fact that we have all original woodwork, plaster walls in good condition, a few original decorative leaded glass windows, and a gorgeous brand new finished master suite. We have a 5 bedroom 3 bath house with a finished basement family room and playroom, plus a patio. In our town, that is a very rare find. But with all of that, comes the crappy original kitchen layout and back porch/bathroom hack. What we discovered when we looked at homes 6 years ago is that there were FAR worse. Mold, scary DIY electrical, refrigerators that couldn't be opened, and absolutely terrible upkeep and maintenance. It was bad...really bad. So when we found our house, trust me when I say this, it was a total steal and we loved it. Except the kitchen. :) Trust me, I get the rebuild idea. I get it. I'm sure many of you see this and read this and think, "Money pit! Run away!!!" :) But not all of us can or want to tear down houses or replace absolutely everything. If we actually tore down our house and rebuilt it, it would cost more than 2-3x the current value to rebuild it with the same quality and materials and finishes. I appreciate all the warnings and suggestions to consider that, but it just isn't going to happen.

@iris everyone here always says knock down to build on. But adding a floor is quite common here and I presume people do it it because it costs less. I know someone who added a floor and their build price was higher than I thought it would be but still many hundred thousands less than my new build. Are you working with a builder too? I would highly recommend double checking all with a builder. Making sure they have actually seen your home and are assessing it’s fitness for this not general idea. Not that it is the same but just as an example, when we were looking to buy/build in 2017, our builder said generally (take that for what you want it to be) about 900k to add a floor and gut the existing house. To build new more like 1.2 million. He was right on build cost so I’m guessing he might be close on add on cost too. Again I share only as an example of what our process was like.

I think Jennifer Hogan's suggestion is a good one, if there is no possibility of converting the attic to bedroom and bath in the future. I imagine taking out the stairs is relatively expensive. So the question would be would that be enough to make that very small room back into a bedroom? Would it add about three feet to in width? I would add a window to the smallest bedroom. The only other thing I would do is move the entry to the main bedroom down the hall or use that space for a linen closet and move the entry close to the other bedrooms and the stairs.