I have an old house with a new roof. It turns out, the end rafters are moldy. I have been ripped out the fascia and soffit on the gable side because they were somewhat moldy and water-damaged. How do I remove the old end rafters and replace them with new ones without having the roof sag? Obviously, I can't just nail a new rafter to the old--I need to get rid of the mold. Thanks.