Roofing assemblies shall be surfaced in compliance with the product approval. Surfacing shall be in sufficient quantity to comply with the required fire classification. Aggregate surfacing shall not be used on slopes greater than 3:12. Aggregate shall be embedded in a flood coat of bitumen applied over a prepared top ply.
On slopes of 3:12 or less, not less than 400 pounds (182 kg) of roofing gravel or 300 pounds (145 kg) of slag per square shall be applied. A minimum of 50 percent of the total aggregate shall be embedded in the flood coat of bitumen. Aggregate shall be dry and free from dirt and shall be in compliance with the sizing requirements set forth in ASTM D 1863. A building official may request a test to confirm compliance with these requirements.
On inclines greater than 3:12, a smooth surface coating shall be applied.
Mineral surfaced cap sheet applications shall not require any additional surfacing unless required with the particular assembly for a fire classification.
All smooth surface applications shall be coated with an aluminized or emulsion coating, having a valid and current product approval and shall be in compliance with the application instructions in said product approval. Coating quantity shall be in compliance with the required fire rating classification for the structure.