Disclosed is a shingle that uses a polyester sheet as a substrate layer. The polyester sheet has a sufficient weight and is needled and formed from two layers to resist shrinking upon cooling after the heated asphalt layers are applied to the polyester substrate sheet 102. In addition, additives may be included in the asphalt to lower the softening point temperature of the asphalt that further reduces shrinking of the polyester substrate 102 or allows other polymers that are more fire retardant to be used. Fire retardants can be placed in the polyester sheet fibers, placed in the bonding agent for the polyester fibers, or the polyester sheet can be coated with the fire retardant. Alternatively, or in addition to treating the polyester sheet 102 with fire retardant, fire retardant materials such as ammonium sulfate can be added to the liquid asphalt prior to application of the asphalt layers.