RoofingCode: Section 1505

Fire Classification

1505.1 General. Roof assemblies shall be divided into the classes defined below. Class A, B and C roof assemblies and roof coverings required to be listed by this section shall be tested in accordance with ASTM E 108 or UL 790. In addition, fire-retardant-treated wood roof coverings shall be tested in accordance with ASTM D 2898. The minimum roof covering installed on buildings shall comply with Table 1505.1 based on the type of construction of the building.

Code Interpretation

This section implies that all roof materials must be tested for fire ratings. Materials are tested alone and within the roof assembly. Testing must be completed by an accredited testing agency in accordance with ASTM E 108 or UL 790. The test determines the flame spread over a specific time period.

The class of the material is defined by the code as follows:

• Class A roof assemblies are those that are effective against severe fire test exposure.

• Class B roof assemblies are those that are effective against moderate fire test exposure.

• Class C roof assemblies are those that are effective against light fire test exposure.


WaterproofingCode: Section 1807

Dampproofing and Waterproofing

1807.3.1, Walls. Walls required to be waterproofed shall be of concrete or masonry and shall be designed and constructed to withstand the hydrostatic pressures and other lateral loads to which the walls will be subjected.


Code Interpretation

This section implies that all walls that require waterproofing shall be constructed of concrete or masonry and have sufficient structural integrity to withstand hydrostatic pressure and lateral loads.

The waterproofing applied at the walls shall consist of one of the following membranes:

• Two-ply hot mopped felts

• 6-mil (or greater) polyvinyl chloride (PVC)

• 40-mil polymer modified asphalt

• 6-mil polyethylene

The waterproofing should be applied a minimum of 12 inches above the highest point of the ground water table. The membrane joints shall be lapped in accordance with the membrane manufacturers latest printed requirements.