What is Shaft Framing?
Shaft framing refers to the construction of walls that enclose vertical shafts within a building. These shafts typically house elements like elevators, stairwells, and other service utilities. Instead of traditional concrete masonry, shaft framing often utilizes lighter materials and methods, providing a more efficient and cost-effective alternative.
While the specific materials and methods vary depending on the building's design and code requirements, common approaches include:
- Metal Stud Framing: This is a popular choice for its speed of construction, relatively low weight, and ability to achieve the necessary fire ratings. Manufacturers like ClarkDietrich offer fully tested and approved assemblies for shaftwall construction using metal studs. ClarkDietrich Shaftwall Systems
- Wood Framing: Wood framing is sometimes employed, particularly in smaller buildings. However, this typically requires fire-retardant treatment and adherence to specific building codes. WoodWorks provides guidance on shaft wall solutions for wood-frame structures.
- Concrete: While less common as a primary framing material for shaft walls in modern construction due to its weight and cost, concrete can be integrated for structural support or specific fire-rated sections. Historically, concrete was the dominant material before lighter alternatives emerged.
Purpose and Importance
Shaft walls are crucial for building safety and functionality:
- Fire Protection: They act as fire-rated barriers, preventing the spread of fire and smoke within the building. National Gypsum highlights the fire-resistance aspect of shaftwall enclosures.
- Structural Support: They provide structural support to the shaft elements they enclose and contribute to the overall stability of the building.
- Code Compliance: Building codes mandate specific fire-resistance ratings and construction methods for shaft walls, ensuring occupant safety. USG provides catalog information on shaft wall systems.
Shaft framing was initially developed for high-rise buildings needing enclosures around vertical shafts as a lighter alternative to concrete masonry construction.
Note on Terminology
It's important to note that the terms "shaft wall" and "chase wall" are sometimes used interchangeably, even though there can be subtle differences in their application and implications.
