My boyfriend and I opted to buy a 246-year-old farmhouse. It's been maintained really well over the years, but we noticed that in several rooms around the perimeter (most likely due to settling) the hardwood floors are uneven and raised. The 1st floor bedroom is raised about 3 inches so that the bedroom door doesn't open all the way because of it. Is there cost-efficient way to take care of this without hiring a professional? We're both DIYers with some basic home improvement know-how.

Thanks!