Your rental start-up costs would be amortized on your Schedule E, not a Schedule C. Your start-up costs are accumulated until you become operational. Expenses such as pre-operational acquisition costs, investigation costs, proof-of-concept costs are included in start-up costs. In the year you become operational you can deduct $5,000 of start-up costs with the balance spread over 180 months beginning with the first month you are operational. You would list this expense in your return as “Start-Up Expense Amortization.”
Improvements and betterments to your rental property, however, would be included in the depreciation base for this asset.