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Home / Assemblies / UL W118
UL W1181.5-hr Fire RatingFloor/CeilingLoad-BearingSTC 58
Wood JoistMineral WoolHigh STCDesign

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

UL-listed 1.5-hour fire-rated wood joist floor/ceiling assembly. 2x12 wood joists at 16" o.c. with R-30 mineral wool, single layer of 5/8" Type X gypsum board ceiling.

Cross-Section Diagram

12345FLOOR/CEILING ASSEMBLYSECTION · NOT TO SCALE5 LAYERSsee legend for ① ② ③
Legend
1Floor covering(varies)
23/4" OSB subfloor(3/4")
32x12 wood joists at 16" o.c.(11.25")
4R-30 mineral wool
55/8" Type X gypsum board(5/8")

Specifications

Fire Rating
1.5-Hour
STC Rating
STC 58
Load Bearing
Yes
Total Thickness
13.38"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
W118
Assembly Type
Floor/Ceiling
Test Standard
UL 263
Construction Group
Light Frame
Number of Layers
5 layers

Applicable Codes

IBC 2021 §722

Construction Summary

2x12 wood joists at 16" o.c. with R-30 mineral wool, single layer of 5/8" Type X gypsum board ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23/4" OSB subfloor3/4"
32x12 wood joists at 16" o.c.11.25"
4R-30 mineral wool—
55/8" 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.