Do I keep depreciating a roof on a rental property which has been replaced before its 27.5 life?

[2015taxms]

I replaced the roof on a rental property which had not been fully depreciated. I will depreciate the new roof, bur what happens to the unused depreciation on the old roof?

[Carl]

Why is the depreciation unused? Are you selling the property? Are you converting it to personal use and moving in to use it as your primary residence now? It matters.
If you're selling it, then you have nothing to deal with on unused depreciation, since all previously taken depreciation is recaptured in the year you sell it, and you pay taxes on that recaptured depreciation in the year you sell it.
If you're moving into it, then the previously taken depreciation is held and suspended "in limbo" until you do sell or otherwise dispose of the property.

[georgek1]

None of the items mentioned here are relevant in Tax Accounting. Turbotax calculates the Taxes according to the Tax Accounting Rules. Forms are generated according to the Accounting Rules adopted by the IRS.

[2015taxms]

the roof had to be replaced before the 27.5 years of depreciation was reached. the property continues to be rented

[georgek1]

Follow the Interview Process in Turbotax. This situation is handled properly there. Look at the Answer I gave first.

[georgek1]

Sometimes an Asset has to be replaced before it's Tax Life is completed. For example, Roof on a Rental Property is depreciated at 27.5 years of Tax Life. Actual usage could be less.

If the Roof is replaced before 27.5 years of usage, the Asset is written down to value 0. There is a Form for Write Down. The Value of the Write Down is calculated there and then transferred to 1040.

The New Roof with the Actual Cost of the Roof is depreciated starting on the Day of installation. 

Turbotax Home and Business Version will do these adjustments and bring in the associated forms through the Interview Process.

[Carl]

If this is the poster's scenario, then this answer is spot on, assuming that this is not the original roof on the house at the time depreciation started.

[TaxGuyBill]

In other words, go into the "asset" of the old roof and 'sell' it for $0.  Then the remaining basis will end up as a loss (you are 'using' the 'remaining depreciation'), so it will usually save you taxes.

If the old roof was part of the original depreciation of the entire house, it can get MUCH more complicated.

[georgek1]

Yes. If it is the Original Roof, then Write Down cannot be used. But the Owner is depreciating the Roof. This means that it is not the Original Roof that came with the Structure. Therefore there is a Value of the New Roof that is being depreciated.

[2015taxms]

What is the number of the form for the write down?

[georgek1]

Form is 4797. It is for Sale of Business Property and Involuntary Conversions of Assets.