The depreciation rate for a new roof seems to clearly be 27.5 years. If the roof only lasts 12 years then the 27.5 depreciation rate still needs to be used for the first new roof expenses. However when the roof is replaced with a second new roof in12 years I believe that the first roof asset is disposed off and the remaining first roof expenses (27.5 - 12 years of expenses) can be depreciated in that year. I believe that the second roof will need to be depreciated at 27.5 years. So in the same year that the second new roof is put on the house 1/27.5 x second new roof expenses can be depreciate. My roof composite shingles have a 40 year life so I am expecting to get 27.5 years out of my new roof.
