Shaft Wall Systems
Shaft wall systems are a specific category of interior fire-rated partitions designed to be installed from only one side. Using very few fasteners, Super Stud’s CT shaft wall studs, coupled with gypsum board, tabbed track and J-runner, make safe and secure rated assemblies with up to 4-hour fire resistance. Shaft wall systems were initially developed for high-rise buildings, that needed to have enclosures around vertical chases, stairwells, and elevator shafts: as a lighter alternative to concrete masonry construction. Scaffolding up the inside of these shafts would be expensive and impractical, so every component of the shaft wall system is installed from the inside. CT stud shaft wall systems have been tested with multiple manufacturers of gypsum board liner panels, and can be used in both horizontal and vertical applications. For specific details on manufacturer-specific applications, check with the gypsum company that made the 1″ liner panels and rated sheathing for your system. For information on Super Stud CT studs, see the resources and details below.
A vertical shaft wall system starts at one corner or up against an adjacent column or wall using a vertical segment of tabbed track. At the top and bottom of the wall, either J-runners or tabbed track or J track may be used. The 1″ leg of all tracks should be towards the installer, and the longer leg should be away from the installer. Note that both J-track and tabbed track have their longer leg 2-1/4″ long; J-runner has a 3″ longer leg. All three styles have a 1″ short leg. Against the vertical tabbed track, install 1″ liner panel between the tabs (fold them out, 2′ on center) and the long leg. This should be a nice, tight fit, and this first piece may be held in place with 2 or 3 optional screws. Vertically, the liner panel should be cut up to 1″ shorter than the wall cavity. This will allow it to be lifted in place over the near leg of the bottom track, and still fit in the wall. See specific Underwriters Laboratories (UL) design information for how wide the permissible gap can be at the top of the wall, and what type of fire-caulk must be used to fill this gap. Note that liner panels can have horizontal butt joints; no blocking is required behind these joints in most assemblies if there are no gaps at these joints.
After this first liner panel is in place, a CT stud should be installed over the tapered (vertical) edge of the panel. The “T” side of the CT stud should be on the far side of the wall, away from the installer. It does not matter if the tabbed side of the “T” or the solid side of the 1″ gap goes over the board first: these studs may be installed either way. The important orientation is for the 1″ liner panel and the “T” side of the stud to be on the far side of the wall, and the cavity or “C” side of the stud to be towards the installer. The studs may have either a 3/4″ or 1″ gap at the top, depending upon the UL assembly requirements. Once the CT stud is in place (no screws required in most cases) the next liner panel is slid in place to complete the bracing of the CT stud. This progression of liner panel and CT stud continues to the next corner or the end of the wall. See the below details for options for both inside and outside corners.