B
HomeLibrariesCopilotSearchProjectsBookmarks
FeedbackHelp Desk
Libraries
Building Codes
Code LibraryIBC — BuildingIRC — ResidentialIFC — FireIPC — PlumbingIMC — MechanicalIFGC — Fuel GasIECC — EnergyNEC — ElectricalModel Codes
Specifications
CSI SpecificationsDOT SpecsTransit SpecsUSACE
Standards
TransportationRailroadFire SafetyAccessibilityStructural
Tools & References
DiagramsAssembliesProductsCalculatorsChecklistsPermits
PricingLog in
Home / Assemblies / UL W126
UL W1263-hr Fire RatingFloor/CeilingLoad-BearingSTC 46
Wood JoistGypsum BoardMineral WoolDesign

Wood Joist Floor/Ceiling — 3 layers 5/8" Type X gypsum board

UL-listed 3-hour fire-rated wood joist floor/ceiling assembly. 2x12 wood joists at 16" o.c. with R-30 mineral wool, 3 layers of 5/8" Type X gypsum board ceiling.

Cross-Section Diagram

1234567FLOOR/CEILING ASSEMBLYSECTION · NOT TO SCALE7 LAYERSsee legend for ① ② ③
Legend
1Floor covering(varies)
23/4" plywood subfloor(3/4")
32x12 wood joists at 16" o.c.(11.25")
4R-30 mineral wool
55/8" Type X gypsum board(5/8")
65/8" Type X gypsum board(5/8")
75/8" Type X gypsum board(5/8")

Specifications

Fire Rating
3-Hour
STC Rating
STC 46
Load Bearing
Yes
Total Thickness
14.62"
Source / Publisher
UL (Underwriters Laboratories)
Design Number
W126
Assembly Type
Floor/Ceiling
Test Standard
UL 263
Construction Group
Light Frame
Number of Layers
7 layers

Applicable Codes

IBC 2024 Table 722.1NFPA 5000

Construction Summary

2x12 wood joists at 16" o.c. with R-30 mineral wool, 3 layers of 5/8" Type X gypsum board ceiling

Material Layers

LayerMaterialThickness
1Floor coveringvaries
23/4" plywood subfloor3/4"
32x12 wood joists at 16" o.c.11.25"
4R-30 mineral wool—
55/8" Type X gypsum board5/8"
65/8" Type X gypsum board5/8"
75/8" 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.