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Home / Assemblies / UL W165
UL W1651-hr Fire RatingFloor/CeilingLoad-BearingSTC 52
Wood JoistDesign

Wood Joist Floor/Ceiling — single layer 5/8" Type C gypsum board

UL-listed 1-hour fire-rated wood joist floor/ceiling assembly. 2x10 wood joists at 24" o.c., single layer of 5/8" Type C gypsum board ceiling.

Cross-Section Diagram

1234FLOOR/CEILING ASSEMBLYSECTION · NOT TO SCALE4 LAYERSsee legend for ① ② ③
Legend
1Floor covering(varies)
23/4" plywood subfloor(3/4")
32x10 wood joists at 24" o.c.(9.25")
45/8" Type C gypsum board(5/8")

Specifications

Fire Rating
1-Hour
STC Rating
STC 52
Load Bearing
Yes
Total Thickness
11.38"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
W165
Assembly Type
Floor/Ceiling
Test Standard
CAN/ULC-S101
Construction Group
Light Frame
Number of Layers
4 layers

Applicable Codes

IBC 2021 Table 722.1

Construction Summary

2x10 wood joists at 24" o.c., single layer of 5/8" Type C gypsum board ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23/4" plywood subfloor3/4"
32x10 wood joists at 24" o.c.9.25"
45/8" Type C 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.