Re: removing knotty pine wainscotting
Can you post pictures of the wainscoting and drywall, particularly where they meet?
It is unlikely that there is nothing behind the wainscot, it would be extremely drafty otherwise. Without seeing the issue, it will be hard to say just how much work it will be to remove the wainscot and repair the wall. It's possible that you'd need to strip the wall from floor to ceiling and replace the drywall and everything. You may (probably ) be able to just remove the wainscot and fill in the drywall.
I suffer from CDO ... Its like OCD, but in alphabetical order, LIKE IT SHOULD BE!!!