No matter how long you owned the property or how old the structure is, rental depreciation starts with the full 27.5 years when you convert it from personal to a rental. If you are seeing something different, you are either misunderstanding what you are seeing, or you are doing something wrong when listing the property as business property. If you can't figure it out here, you may need to call customer support.
Separately, the basis for depreciation is either your cost basis or the fair market value on the date of conversion, whichever is lower. Your cost basis is what you originally paid, plus the cost of any permanent improvements you made. So if you bought for $100,000, remodeled the kitchen for $20,000, then your basis for depreciation is $120,000, even if the market value is much higher after all this time. --- And actually your basis is less, because you can't depreciate the part of the cost that is from the land, since land doesn't depreciate.
