Which type of building construction is primarily made of wood and commonly found in mercantile and residential structures?

The correct answer is that the type of building construction primarily made of wood and commonly found in mercantile and residential structures is classified as Type 5, or Wood Frame construction. This type of construction is characterized by its use of wood as the main structural element, making it lightweight and flexible. Type 5 construction is prevalent in single-family homes, townhouses, and smaller commercial buildings due to its cost-effectiveness and ease of construction.

Type 5 structures typically consist of wood studs, beams, and other materials, often with the exterior covered in siding or other finishes. This type of construction also allows for a high degree of design versatility while being relatively quick to build, which is why it is popular in both residential and mercantile applications.

The other types mentioned serve different purposes and use different materials. Type 2, or Noncombustible construction, primarily utilizes materials that are not susceptible to combustion, such as steel and concrete. Type 3, known as Ordinary Construction, includes both noncombustible and combustible materials but often has a mix of different structural elements. Type 4, Heavy Timber, utilizes large wooden members, which can impart different fire resistance characteristics but is generally more robust than standard wood framing. The distinction is clear