This 40-yr. Guarantee is more than twice other roofing firms supply in Jamaica Plain Massachusetts. G.F. Sprague can offer a 40-yr guarantee due to our considerable training, certifications, and expertise. We're one of a couple contractors who takes a DCAM License (#08-0165). We at G.F. Sprague supply all of our customers with a "5 Star" service. We should be certain you believe that your roofing job, and you, were treated as if you were getting preferential treatment that is 5 Star at a high end lodging facility.