The IRS De Minimis Guideline cite mentioned in the answer above states the following:
The requirements of the safe harbor election for small taxpayers are:
The total amount paid during the taxable year for repairs, maintenance, improvements, or similar activities performed on such building property doesn't exceed the lesser of-
- Two percent of the unadjusted basis of the eligible building property; or
- $10,000 (for questions about how to calculate the unadjusted basis, refer to "Figuring the Unadjusted Basis of Your Property" in Publication 946
Hope this helps
