What problems hurt a home appraisal when refinancing?

When refinancing, the same issues that lower a purchase appraisal apply: poor condition of the roof and foundation, deferred maintenance, and a shortage of recent comparable sales nearby. Comparable sales should generally be located within a mile of the home, in similar condition, and close in age, square footage, and number of rooms. A low appraisal can reduce the amount a lender will let you borrow against the property.