Roofing shingles are another type of roofing material coated with oxidized bitumen. The bitumen is cross linked or oxidized and is coated onto the roofing felt in a manufacturing step. Generally, the asphalt is filled with stone dust. The asphalt is heated to about 400°-450° F. and spread on and pressed into the roofing felt. Roofing granules are then fed onto the saturated asphalt felt and pressed in.

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