An investor who lives in the US has a single family home which has been fully depreciated. It is on the beach and has only been rented. It has never been used by the owner.

One of the outside walls is rotting away. A contractor is brought in and the wall is replaced. For tax purposes, is the cost of the new wall considered a repair? That is, can you deduct the cost of the new wall in the current year or does the cost of the wall have to be depreciated over several years? If it is the latter, can Section 179 bonus depreciation be taken?