The industry standard for the warranty on the roofing material is about 20 years. The standard for the warranty of the workmanship and labor on the roof is about one or two years, according to Reliableroofing.biz.
The manufacturer's warranty could extend up to a lifetime depending on the material that is being used for the roofing.
Certificates of warranties should be given by the contractor. On the labor warranty, the certificate should indicate the terms of the warranty, what is covered by the warranty and what can make it void. In case maintenance is required, the warranty certificate should be precise on what should be done and how often, as stated by Therosieonthehouse.com