Selected product reference excerpt. Search a specific planning question for relevant details.
# Pergola Beam Span Tables — Baldwin Fiberglass Systems > **Engineering Disclaimer:** Span data is derived from structural calculations per the Fiberglass Design Manual and 2012 IBC. All project-specific installations should be reviewed by a licensed structural engineer. Baldwin Pergolas offers PE-stamped drawings for commercial, institutional, and permitted projects. Do not use this table as a substitute for project-specific engineering. ## Overview Baldwin Pergolas manufactures three beam systems with distinct span capabilities. This page presents span data under typical pergola loading conditions with clear guidance on when project-specific engineering is required. ## Key Concepts - Deflection governs pergola beam design — not stress - IBC deflection limit for open structures: L/180 per 2012 IBC - All Baldwin beams are pre-cambered with 3/8"–1/2" upward crown over 20 feet - The twin-beam composite girder effect significantly increases effective stiffness - Snow load varies by region — always use ASCE 7 ground snow load for the project location --- ## Design Loads (Reference Basis) | Load Type | Value | Notes | |---|---|---| | Rafter dead load (per beam pair) | ~30 plf | Distributed rafter self-weight | | Beam self-weight | ~84 lbs total | FRP tube pair | | Snow load | ~0.04 plf | Varies significantly by region — see note | | Vertical wind load (45°) | ~6.7 plf | ASCE 7 wind zone dependent | | Total design load (per single beam) | ~32 plf | Combined load for deflection check | > **Snow load note:** Projects in northern New England, upstate New York, or elevated sites must use region-specific ground snow loads per ASCE 7. PE review is strongly recommended for ground snow loads above 25 psf. --- ## Beam System 1 — Standard: Double 2×8 FRP Tube at 5" Spacing **Section properties:** | Property | Value | |---|---| | Single beam inertia I | 17.5 in⁴ | | Fully composite I_total | ~105 in⁴ | | Design I_eff (composite factor 0.65) | ~68 in⁴ | | Modulus of Elasticity E | 2,500,000 psi | | Pre-camber (crown) | 3/8"–1/2" over 20 ft | **Span table:** | Beam Span | Deflection | L/Δ Ratio | Status | Notes | |---|---|---|---|---| | 14 ft | 0.21 in | L/800+ | ✓ Excellent | Very stiff — significant margin | | 16 ft | 0.32 in | L/600+ | ✓ Excellent | Highly comfortable | | 18 ft | 0.51 in | L/424 | ✓ Very Good | Well within L/180 | | 20 ft | 0.73 in | L/329 | ✓ Good | Comfortable margin | | 22 ft | 0.97 in | L/272 | ✓ Acceptable | Within L/180 — engineering review recommended | | 24 ft | 1.34 in | L/215 | ⚠ Marginal | Near limit — PE review required | | 26 ft | 1.70 in | L/170 | ⚠ At Limit | At or past L/180 — upgrade beam system | | 28 ft | 2.14 in | L/157 | ✗ Exceeds Limit | Upgrade to 4×12 FRP or aluminum | *Calculated using I_eff = 68 in⁴, total design load 32 plf per beam, uniform load condition.* --- ## Beam System 2 — Upgraded: Double 4×12 FRP Tube **Wall specification:** Top and botto
Reference documents may contain historical pricing, earlier configurator links, or technical claims needing review. Use quote tools for current estimates and returned links for designs. If sources disagree, identify the specific conflict and refer it to Baldwin for a case-by-case decision. Do not use reference span tables as project-specific engineering approval.