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Home / Assemblies / UL W168
UL W1681.5-hr Fire RatingFloor/CeilingLoad-BearingSTC 60
Wood JoistGypsum BoardFiberglass BattHigh STCDesign

Wood Joist Floor/Ceiling — 2 layers 5/8" Type X gypsum board

UL-listed 1.5-hour fire-rated wood joist floor/ceiling assembly. 2x10 wood joists at 24" o.c. with R-30 fiberglass batt, 2 layers of 5/8" Type X gypsum board ceiling.

Cross-Section Diagram

123456FLOOR/CEILING ASSEMBLYSECTION · NOT TO SCALE6 LAYERSsee legend for ① ② ③
Legend
1Floor covering(varies)
23/4" OSB subfloor(3/4")
32x10 wood joists at 24" o.c.(9.25")
4R-30 fiberglass batt
55/8" Type X gypsum board(5/8")
65/8" Type X gypsum board(5/8")

Specifications

Fire Rating
1.5-Hour
STC Rating
STC 60
Load Bearing
Yes
Total Thickness
12"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
W168
Assembly Type
Floor/Ceiling
Test Standard
UL 263
Construction Group
Light Frame
Number of Layers
6 layers

Applicable Codes

IBC 2021 §722IBC 2024 §722NFPA 5000

Construction Summary

2x10 wood joists at 24" o.c. with R-30 fiberglass batt, 2 layers of 5/8" Type X gypsum board ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23/4" OSB subfloor3/4"
32x10 wood joists at 24" o.c.9.25"
4R-30 fiberglass batt—
55/8" Type X gypsum board5/8"
65/8" Type X gypsum board5/8"

Important Notice

This assembly listing is for reference only. Always verify against the current UL Product iQ database before specifying in construction documents. Material substitutions may void the fire rating. Consult with a qualified fire protection engineer for project-specific requirements.