During 2013 to mid-2015 (before renting) I did approximately $35K worth of improvements but again these were not added onto to the cost basis of the rental - I used the purchase price.
Unfortunately, that is a mistake that you can not correct yourself. It's not as simple as one may think. You need professional help for this in order to know it's fixed correctly. While TurboTax does include the 3115 you need to file in order to fix this, your situation is not a simple one by any stretch. Please seek professional help to get this done correctly so it doesn't come back to bite you. The cost of professional help will seem like a pittance in comparison to the fines and penalties the IRS will assess if things are not done right.
