Engineered Lumber Span Tables
Span TableAllowable span tables for LVL beams, I-joists, and glulam beams under standard residential loading conditions. Includes floor joist spans, beam spans, and header spans.
I-Joist Floor Spans — 40 psf Live Load + 10 psf Dead Load, L/360
Source: Typical manufacturer published values (Weyerhaeuser TJI, Boise BCI)| I-Joist Depth | 12" o.c. | 16" o.c. | 19.2" o.c. | 24" o.c. |
|---|---|---|---|---|
| 9-1/2" | 18'-2" | 16'-6" | 15'-5" | 14'-2" |
| 11-7/8" | 22'-0" | 19'-6" | 18'-2" | 16'-9" |
| 14" | 25'-6" | 23'-0" | 21'-6" | 19'-8" |
| 16" | 28'-0" | 25'-6" | 23'-6" | 21'-9" |
LVL Beam Spans — Single Ply 1-3/4" Width, Floor Load
Source: Typical manufacturer published values (residential floor beam, 40+10 psf)| LVL Depth | Single Ply Max Span | Double Ply Max Span | Triple Ply Max Span |
|---|---|---|---|
| 7-1/4" | 6'-0" | 8'-6" | 10'-0" |
| 9-1/2" | 8'-0" | 11'-6" | 13'-6" |
| 11-7/8" | 10'-6" | 14'-0" | 16'-6" |
| 14" | 12'-6" | 16'-6" | 19'-0" |
| 18" | 15'-6" | 20'-0" | 24'-0" |
Glulam Beam Spans — Floor Load (40+10 psf)
Source: APA/EWS, AITC typical values for 24F-V4 Douglas Fir| Glulam Size (width x depth) | Max Span (L/360) | Tributary Width 8 ft | Tributary Width 12 ft |
|---|---|---|---|
| 3-1/8" x 9" | 10'-6" | 8'-6" | 7'-0" |
| 3-1/8" x 12" | 14'-0" | 11'-6" | 9'-6" |
| 5-1/8" x 12" | 16'-0" | 14'-0" | 12'-0" |
| 5-1/8" x 15" | 20'-0" | 18'-0" | 15'-6" |
| 6-3/4" x 18" | 28'-0" | 24'-0" | 21'-0" |
Applicable Codes & Standards
- • IRC R502 — Wood Floor Framing
- • IRC R602.7 — Headers (engineered wood)
- • IBC 2304.12 — Engineered wood products
- • ASTM D5055 — Standard Specification for Wood I-Joists
- • ASTM D5456 — Standard Specification for SCL Products
- • ANSI/AITC A190.1 — Glulam Standard
- • NDS (National Design Specification for Wood Construction)
How to Use These Tables
These span tables provide approximate allowable spans for common engineered lumber products under standard residential loading conditions. They are intended as general reference — always verify with the specific manufacturer's published design tables or engineering software for actual project design.
Important Limitations
- Spans shown assume simple-span conditions (supported at both ends, no continuity).
- Floor spans assume L/360 deflection limit for live load and L/240 for total load per IRC.
- Beam spans assume a specific tributary width — the area of floor the beam supports. Wider tributary widths reduce allowable span.
- Manufacturer-specific design values vary. The spans shown represent typical mid-range values; actual allowable spans may be higher or lower depending on the specific product.
- Local code amendments, snow loads, and special loading conditions may require additional analysis.
For actual beams and headers, use the manufacturer's free design software: Weyerhaeuser ForteWEB, Boise Cascade BC Calc, or LP SolidStart Software. These tools account for product-specific properties, load combinations, and deflection criteria.