ALL the assets listed for depreciation need to be sold so you need to allocate the sale price & costs of sale between all of them. You need to get a pencil and paper and make yourself a table so you have all the info needed when the program asks for it since the program will not do the allocation for you.
A simple allocation example using 100,000 of assets and a sale price of 200,000 and cost of sale of 20,000 :
assets original basis % of total basis sales price cost of sale
house 70,000 70% 140,000 14,000
land 20,000 20% 40,000 4000
roof 10,000 10% 20,000 2000
totals 100,000 100% 200,000 20,000
