The U.S. housing recession is so deep that an average home takes nearly a year to sell. In the hardest hit areas, it can take several years. Just ask residents of Detroit, Nevada and parts of Florida, Arizona and southern California. As if that were not enough, there are hidden costs associated with an unsold home in which the owner still lives, including upkeep and repair costs incurred while the house is on the market. 24/7 Wall St. looked at the ten most expensive repairs and what they cost. Some frequently needed repairs can cost over $10,000 to fix.