Since the sales price was part of the house, you can put zero for sales price.
Actually, with TTX you can't do that with depreciable assets. If you do, then you show a gain on the sale of the property/structure after depreciation recapture, and a loss on the sale of the roof after depreciation recapture. TTX can't and still doesn't deal with that correctly mathematically, and will not generate an error on the final review. Basically, the 4797 will be wrong. Confirmed on TTX 2019 and prior. Not yet confirmed on TTX 2020.
