Do I use values of roof or home when calculating FMV for loss of roof during Hurricane harvey, when using the Safe Harbor Method?

[2018legacy]

I understood, how to look in Table 5 to calculate the decrease in FMV. But where exactly does that decrease get entered in TurboTax for my loss? Turbo Tax just asks for "Cost basis" , reimbursement from insurance, FMV value before event and FMV value after event. IS that decrease applied to my home value or roof value? and then the adjused FMV entered into FMV after the event?
What do I use for  "FMV (whether its home or roof) before event" ?

[Coleen3]

There is no absolute way to do this. FMV before should not be too difficult, what your home would have sold for before the storm. FMV after, what would be the value after. You can use the value of the roof as a guide for the decrease in FMV.