All of the 1245assets can be added together if you wish and all of the 1250 assets can be added together and leave the land separate ... by doing so you would fill in the correct sections of the form 4797 correctly. And using my method will get them put in the correct sections even though you don't like how the roof looks ... all 1250 property will balance out automatically.
FYI ... I am an Enrolled Agent with the IRS and I taught this tax course for several years so I know the correct way to do this however many others do it differently and if it will hold up in an IRS audit is iffy at best.
