Which class of construction is defined by masonry exterior walls and noncombustible roof and floor materials?

The classification involving masonry exterior walls paired with noncombustible roof and floor materials is accurately described by Class 4, known as Masonry Noncombustible. This class is specifically characterized by its construction materials, emphasizing the use of masonry to provide superior fire resistance compared to other building classifications, particularly those that utilize combustible materials.

Class 4 construction features walls made of materials like brick, stone, or concrete, which can effectively impede fire spread, while the noncombustible materials used in the roof and floor further enhance the building's overall fire safety. This distinction is important for insurance underwriting and risk assessment, as buildings constructed in this manner are generally considered to be at a lower risk of fire damage compared to those made from combustible materials.

Option B, Modified Fire Resistive, typically includes buildings that have some fire-resistive features but do not fully meet the standards of Class 6. Option C, Fire Resistive, generally refers to construction that has significant fire-resistive protections, but often involves higher degrees of treatment or thickness in materials. Lastly, Class 3, Frame, involves structures primarily made from wood or other combustible materials, which do not provide the same level of fire resistance as Class 4. Understanding these classifications helps