Question: REALLY Uneven Floors

Q: I own a 200 year old farmhouse, I bought it as a fixer-upper. The biggest problem that I’m running into is that none of the floors are anything close to even. I don’t mind the floors having a natural slope – that makes it easy to know where your pen goes when you drop it – but I’m worried about installing new flooring. How will the unevenness affect the flooring? Are there underlayments that could help? What would the best flooring option be for something like this?
A: This will matter heavily on how much of a difference you see in the height of the floor currently. Good underlayments can typically easily make up for differences of 1/16″ without problem and some can make up for a bit more.
The right way to do this would be to determine if this is because of the subfloor or just the current flooring. I have been in a few much older homes which were built on log foundations, so there was a natural bit of wave to the home as it settled over time. A problem like this is at the very foundation, which makes it quite the job to fix.
In your case, if you determine it is the foundation, there are two options. The best fix is to fix the root of the problem (subfloor or possibly even the foundation). Your other option here would be to sand the floor flat, then install a new floor over the top of it. With floors, you want the subfloor to be smooth and flat. A very slight slant, say something like 1/4″ difference over 10-15ft or more can be installed over with little to no worry, especially with a floating installation. Any differences that is more extreme than this cause problems and should be remedied.