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Home / Assemblies / UL W108
UL W1083-hr Fire RatingFloor/CeilingLoad-BearingSTC 45
Wood JoistGypsum BoardMineral WoolDesign

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

UL-listed 3-hour fire-rated wood joist floor/ceiling assembly. 2x10 wood joists at 16" o.c. with R-30 mineral wool, 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 16" o.c.(9.25")
4R-30 mineral wool
55/8" Type X gypsum board(5/8")
65/8" Type X gypsum board(5/8")

Specifications

Fire Rating
3-Hour
STC Rating
STC 45
Load Bearing
Yes
Total Thickness
12"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
W108
Assembly Type
Floor/Ceiling
Test Standard
UL 263
Construction Group
Light Frame
Number of Layers
6 layers

Applicable Codes

IRC R302.1IBC 2024 Table 722.1IBC 2024 §722

Construction Summary

2x10 wood joists at 16" o.c. with R-30 mineral wool, 2 layers of 5/8" Type X gypsum board ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23/4" OSB subfloor3/4"
32x10 wood joists at 16" o.c.9.25"
4R-30 mineral wool—
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.