54f for repairs

No you can't as section 54F required purchase of immovable property or construction of immovable property

section states that

Where the assessee purchases, within the period of two years after the date of the transfer of the original asset, or constructs, within the period of three years after such date, any residential house, the income from which is chargeable under the head "Income from house property", other than the new asset, the amount of capital gain arising from the transfer of the original asset not charged under section 45

Subjectvto one clause improvement of building