I have an existing asphalt shingle roof that meets a sidewall. Unfortunately, the underlayment does not lap up the wall and there is no step flashing. And of course, the siding and sheathing has now rotted. I am in the process of replacing the siding and sheathing on the sidewall, but am wondering the best way to flash this. I can easily add step flashing to the existing roof, but I can't think of an easy way to add underlayment without removing shingles. Any ideas?
Thanks!
Thanks!