Check for a permanent place of business, telephone number, tax ID number, a business license where applicable.
Do not hesitate to ask to see copies of both liability coverage and workers compensation certificates. If a contractor is not properly insured, you may be liable for accidents that occur on your property. Make sure the coverage runs through the duration of your job.
Check to see if the roofing contractor is properly licensed and bonded. A payment bond will insure no mechanic's lien can be placed on your home because the subcontractors were not paid
Look for a company with a proven track record. The contractor can provide you with a list of completed projects. Call these clients to find out if they are satisfied.
Make sure the contractor is financially stable. A professional roofing contractor can provide financial information about his company. Also ask about payment procedures.
Carefully read and understand any roofing warranties offered, and watch for provisions that would void it.
The lowest bid is not always the best bid. If it sounds too good to be true, it probably is. Many fly-by-night contractors' below-cost bids seem attractive, but these contractors often are uninsured and perform substandard work. Remember, price is only one of the criteria for selecting a contractor.
Keep in mind that in some cases new roofing materials can be applied directly over an existing roof. This is usually possible only if there is one roofing layer already in place and if the sheathing, the boards to which the roofing is fastened, is in good condition. Avoiding unneeded roof stripping may save you a considerable amount of money.