roofs like <a href="http://www.redfin.com/CA/Los-Angeles/1728-Kilbourn-St-90065/home/7072065">this one?</a> or <a href="http://www.redfin.com/CA/Van-Nuys-East/13843-Friar-St-91401/home/4633138">this</a> or <a href="http://www.redfin.com/CA/Woodland-Hills/5554-Franrivers-Ave-91367/home/3271563">this</a> or <a href="http://www.redfin.com/CA/Woodland-Hills/5046-Marmol-Dr-91364/home/4173717">this</a>
Sorry I don't know the answer but I remember watching one of those cable realtor shows and they guy talked about how bad flat roofs are because of, I think, more water damage. He was afraid the house wouldn't pass inspection and he was right.