What type of construction has non-combustible exterior walls but combustible roofing and flooring materials?

The correct choice describes a construction type characterized by non-combustible exterior walls combined with combustible roofing and flooring materials. This construction classification is known as "Class 2 - Joist and Masonry."

In this type of construction, the exterior walls are made of materials that do not ignite easily and can withstand high temperatures without contributing to a fire, thus providing a level of protection. However, the roofing and flooring materials can still be combustible, which introduces a risk factor when it comes to fire safety. By having non-combustible walls, the structure helps to contain any potential fires better than structures with all-combustible materials, while the use of combustible materials in the roof and floor poses certain hazards.

Understanding construction classifications is crucial for properties, as it influences insurance underwriting, risk assessments, and fire safety regulations. The other classifications either incorporate more combustible elements throughout, like Class 1 - Frame, or consist entirely of non-combustible materials in all aspects, like Class 3 - Noncombustible and Class 4 - High-Rise. Thus, "Class 2 - Joist and Masonry" accurately captures the essence of combining non-combustible walls with combustible components elsewhere in the structure.