In order to add the cost of capital improvements (an addition on the home, a new furnace or roof) to your basis, you need documentation. If you don’t have receipts for your expenditures, try getting what you need in another way. For example, contact the contractor or vendor you used for a sprinkler system, new carpeting, or any other improvement and ask for a copy of a paid receipt.
Generally, an unmarried person who maintains a household for dependents and is allowed to compute his or her tax based on head of household rates, which are more favorable than single person rates.