My single layer shingle roof is 25 years old. A licensed contractor can certify the roof for 2 years after making some repairs. I am putting the house on the market and will not spend 8-12K on a roof for a house being listed at 250,000. I read FHA rules allow roof certifications and (if necessary) another shingle layer on roof. Does a certification help move the sale? As a seller I want to move the house with minimal financial impact. Thanks.