Which type of construction is commonly used up to six or seven stories?

Type III construction is characterized by its use of exterior masonry walls and an interior framework of wood. This type of construction is commonly employed in buildings that are up to six or seven stories tall. The materials used provide a good balance between weight, cost, and fire resistance, making it a practical choice for mid-rise structures.

The structural integrity of Type III buildings allows for a lighter construction approach compared to heavier materials, which is suitable for residential and commercial applications in urban settings. The use of wood in the interior framework means that these buildings have some vulnerability to fire, but the masonry exterior provides significant fire resistance from the outside.

In summary, Type III construction is favored for mid-rise buildings due to its composite design, which extends usable height while maintaining manageable weight and cost concerns, making it a common choice for structures in many cities.