A man will show up and offer to clean your gutters or perform a minor roof repair. His repair crew falsely reports that the repairs to the roof appear to have weakened the rafters in the attic. They offer to brace them up so the roof will not collapse. They hammer two-by-four studs between the rafters and the floor of the attic, then charge $100 for each of these "braces." The braces, often called "stiff knees," are not only unnecessary, they can cause damage to the ceilings of rooms below during periods of high wind or heavy snow.