Impact shingles have been around for the past 14 years but have gotten very popular over the last few years. Insurance companies started offering discounts to homeowners if they installed a Class 4 shingle on their home. The discount makes the option very appealing to homeowners. Discounts vary depending on your location in the state and the type of coverage. It is important to contact your agent and discuss the amount of saving you will receive of your premiums. There is a link at the bottom of the page to the Texas Department of Insurance which will explain in detail the Class 4 option.
It is important to understand that the Class 4 does not necessary look much different than a standard laminated shingle and they can be damaged by hail if large the hail is large enough. The key to its strength is how the shingle is manufacturer. It must meet Under Writers Laboratories stick UL 2218 test before it can be called a Class 4 which consist of dropping steel balls on the surface of the shingle to simulate hail stones. Remember if the package does not say UL2218 or Impact Resistance shingle than it is not a Class 4.
The Class 4 discounts apply to almost all metal roofs. The metal roofs still have to meet the UL 22818 test. It very important to understand on metal roofs you must sign a cosmetic wavier on your roof in order to receive the Class 4 discount. Your roof can be dented by the hail storms but still serving its intended purpose. In this case the insurance would say that it is cosmetic and not pay you for a new roof. This should be considered very carefully because metal holds up very well in hail but it is often dented.
The manufacturers that make a Class 4 shingle are Owens Corning, GAF, Tamko, and Malarkey.