I am saying that you can currently deduct the amount for repairs but must capitalize and use depreciation for improvements.
There is not a bright line single factor test to use for determining how much is repair and how much is improvement.
From the link above for the difference between repairs that can be deducted in full as an expense and improvements that have to use depreciation:
"You can deduct the cost of repairs to your rental property, but you cannot deduct the cost of improvements. The cost of improvements is recovered by taking depreciation (see , Depreciation of Rental Property).
Repairs. A repair keeps your property in good operating condition. It does not materially add to the value of your property or substantially prolong its life. Repainting your property inside or out, fixing gutters or floors, fixing leaks, plastering, and replacing broken windows are examples of repairs.
If you make repairs as part of an extensive remodeling or restoration of your property, the whole job is an improvement.
Improvements. An improvement adds to the value of property, prolongs its useful life, or adapts it to new uses. Table 1-1 shows examples of many improvements.
If you make an improvement to property, the cost of the improvement must be capitalized. The capitalized cost can generally be depreciated as if the improvement were separate property. "
Depending on the facts and circumstances, the entire 4K may be repairs or only the portion that restores it to working condition (and does not add to the value, such as an upgrade).
For example, if I had laminate floor and decided to put in oak floor, the repair portion would be the cost to replace the laminate and the improvement portion (the cost of the oak that was more than just replacing laminate) would be an improvement. Had I just replaced the worn laminate with new laminate it would reasonably be all deemed to be repair expense to be currently deducted in full.
Please understand that it is only a difference in timing and that you will, eventually, get to deduct the entire 4K cost whether classifying it as either a repair or an improvement.
Please ask if you need clarification.