I recent replaced the retaining wall on my rental property due to it failing. The retaining wall shares a boundary with my neighbor. I expanded the retaining wall at the request of my neighbor and he contributed 1/3 to the total cost of project. The total cost was about 30k and he contributed 10k. Do I depreciate the retaining wall in my tax return by the full amount (30k) or what my actual cost was (20k)? My neighbor's property is his residence, where my property is a rental property.
I've searched and had not luck, so appreciate any advice.
