I'm not sure if your goal is to track warranties of things installed, or track expenses and the financial side of it. (or both) Have you talked to your accountant? My accountant told me what they wanted to see, and it amounts to about 4 spread sheets. All of my other documentation goes in to some google doc folders.
4 spread sheets? is that 4 different single things? or 4 sheets of things, and what makes the break from one sheet to the next?