USG Cavity Shaft Wall Systems
Part 3: Execution
3.1 Cavity Shaft Wall Erection
A Studs and Liner Panels-Position steel runners at floor and ceiling with the short leg toward finish side of wall. Securely attach runners to
structural supports with power driven fasteners at both ends and max. 24" o.c. With steel frame construction, install floor and ceiling runners
and J-Runners or E-Studs on columns and beams before steel is fireproofed. Remove spray-fireproofing from runners and E-Studs before
installing gypsum liner panels (2-hour steel fireproofing). For other structural steel fireproofing requirements, use Z-shaped stand-off clips
secured to structural steel before fireproofing application.
Cut liner panels 1" less than floor-to-ceiling height and erect vertically between J-Runners. Where shaft walls exceed max. available panel
height, position liner panel end joints within upper and lower third points of wall. Stagger joints top and bottom in adjacent panels. Screw
studs to runners on walls over 16'.
Use steel C-H studs 3/8" to not more than 1/2" less than floor-to-ceiling height, and install between liner panels with liner inserted in the
groove. Install full-length steel E-Studs or J-Runners vertically at T- intersections, corners, door jambs, and columns. Install full-length E-Studs
over gypsum liner panels both sides of closure panels. For openings, frame with vertical E-Stud or J-Runner at edges, horizontal J-Runner at
head and sill, and reinforcing as shown on the drawings. Suitably frame all openings to maintain structural support for wall,
Install floor-to-ceiling steel E-Studs each side of steel hinged door frames and jamb struts each side of elevator door frames to act as
strut-studs. Attach strut-stud to floor and ceiling runners with two 3/8" Type S-1 2 pan head screws. Attach strut-studs to jamb anchors with
1/2" Type S-12 screws. Over steel doors, install a cut-to-length section of J-Runner and attach to strut-studs with 3/8" Type S-1 2 screws.
B Resilient Channels-Install RC-1 Resilient Channels or equivalent horizontally to face of studs, within 6" of floor and ceiling and max. 24"
o.c. Attach channels to studs with 3/8" Type S screws driven through holes in mounting flange. Splice channel by nesting directly over stud;
screw-attach through both flanges. Reinforce with screws at both ends of splice. Install 1/2" x 3" wide continuous gypsum filler strips to top
and bottom runner.
For resiliently attached finish, apply base layer horizontally to resilient channels with end joints staggered; fasten with 1" Type S screws 12"
o.c. Apply face layer vertically with joints staggered; attach to channels with 1-5/8" Type S screws 12" o. c.
C Gypsum Panels-Single layer one side, one hour: apply 5/8" SHEETROCK brand Gypsum Panels, FIRECODE Core, on corridor side.
Position gypsum panel vertically and fasten to studs and runners with 1" Type S Screws 12" o.c.
Double layer one side, two hour: apply base layer to studs with 1" Type S screws 24" o.c. along edges and in the field of the panels. (Apply
face layer vertically and fasten to studs and J-Runners with 1-5/8" Type S screws 12" along the edges and in the field, staggered from
screws in base layer. Joints between base and face layers staggered.) (Attach face layer over base layer with 1-5/8" type S screws 12" o.c.
in the field, along the vertical edges and to the floor and ceiling runners. Face layer attached to base layer with 1 -1 /2" long Type G screws
midway between studs and 1" from the horizontal joint.)
Single layer both sides, two hour; apply gypsum panels to both sides of studs. Fasten gypsum panels with 1" Type S screws 12" o.c. along
the vertical edges and in the field.
Double layer, two hour with Durock Cement Board: install 1-1/2" THERMAFIBER SAFB in stud cavity. Apply base layer of 5/8"
SHEETROCK brand Gypsum Panels, FIRECODE C Core and attach with 1" Type S screws 24" o.c. along vertical edges and in the field.
Install face layer of 1/2" DUROCK Cement Board by lamination to gypsum panels with 4" wide strip of mastic applied with 3/4" notched
trowel midway between studs and fasten to studs with 1-5/8" DUROCK Screws 6" o.c.
Double layer, two hour resilient: apply base layer to resilient channels with end joints staggered; fasten with 1" Type S screws 12" o.c. Apply
face layer with joints staggered; fasten to channels with 1-5/8" Type S screws 12" o.c.
Triple layer, three hour: install three layers of SHEETROCK brand Gypsum Panels, 3/4" ULTRACODE Core. Apply first and second (inner)
layers vertically or horizontally over steel studs. When applied vertically, center joints over studs and stagger min. 24"; otherwise, stagger
joints min. 12". Secure first layer to studs with 1-1/4" Type S self-drilling, self-tapping bugle-head steel screws spaced 12" o.c. Apply third
layer vertically over furring channels with 1-1/4" Type S self-drilling self-tapping bugle-head steel screws spaced 12" o.c. Finish joints with
paper tape and joint compound.
Four layer, four hour: install four layers of 3/4" SHEETROCK brand Gypsum Panels, ULTRACODE Core. Apply first three layers as for
3-hour rating (above). Apply fourth layer vertically or horizontally, with 2-1/4" Type S self-drilling self-tapping bugle-head steel screws spaced
12" o.c. When applied vertically, stagger joints min. 24" from third layer; otherwise, stagger all joints min 12". Finish joints with paper tape
and joint compound.
Horizontal installation, two hour: install three layers of 112" SHEETROCK brand Gypsum Panels, FIRECODE Core, to horizontally installed
CH and/or E-Studs. Install the base layer and attach with 1" Type S screws 24" o.c.; the mid layer in the same manner with joints offset 2' and
attached with 1-5/8" Type S screws 12" o.c.; and the face layer attached with 2-1/4" Type S screws spaced 12" o.c. Place face layer end
joints between studs and secure with 1-1/2" Type G screws 8" o. c.
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