Most trades are licensed through a state governmental agency such as a "home improvement commission". You'll need to find the agency in your state and verify that the tradesmen is, in fact, licensed and in good standing.
How much experience do you have installing my type of roof?
Is the majority of your work in repairs, remodeling or new construction?
Do you work out of an office or another permanent place of business?
Tradesmen such as roofers can price services in three distinct ways:\0121. Time and Material - an hourly rate plus the cost of the materials (which may be marked up).\0122. Flat rate - repair and replace 5 shingles $350\0123. Bid - tradesman provides a comprehensive quote upfront for what the charges will be which includes all labor and material charges.
What other costs, fees or charges should I expect?
Do new roofs qualify for tax credit under the new economic stimulus bill?
Tax credits are available at 30% of the cost, up to $1,500 total, in 2009 & 2010 (ONLY for existing homes, NOT new construction, that are your principle residence) for: metal and asphalt roofs.