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Home / Assemblies / UL L109
UL L1093-hr Fire RatingRoof/CeilingLoad-Bearing
Wood JoistGypsum BoardFiberglass BattDesign

Wood Truss Roof/Ceiling — 2 layers 5/8" Type C gypsum board

UL-listed 3-hour fire-rated wood truss roof/ceiling assembly. Wood trusses at 24" o.c. with R-38 blown fiberglass, 2 layers of 5/8" Type C gypsum board ceiling, 1/2" plywood sheathing.

Cross-Section Diagram

123456ROOF/CEILING ASSEMBLYSECTION · NOT TO SCALE6 LAYERSsee legend for ① ② ③
Legend
1Roof covering(varies)
21/2" plywood sheathing(1/2")
3Wood trusses at 24" o.c.(12"-24")
4R-38 blown fiberglass
55/8" Type C gypsum board(5/8")
65/8" Type C gypsum board(5/8")

Specifications

Fire Rating
3-Hour
Load Bearing
Yes
Total Thickness
15.25"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
L109
Assembly Type
Roof/Ceiling
Test Standard
UL 263
Construction Group
Light Frame
Number of Layers
6 layers

Applicable Codes

IBC 2024 Table 722.1IRC R302.1

Construction Summary

Wood trusses at 24" o.c. with R-38 blown fiberglass, 2 layers of 5/8" Type C gypsum board ceiling, 1/2" plywood sheathing

Material Layers

LayerMaterialThickness
1Roof coveringvaries
21/2" plywood sheathing1/2"
3Wood trusses at 24" o.c.12"-24"
4R-38 blown fiberglass—
55/8" Type C gypsum board5/8"
65/8" 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.