Timber Design Values Reference
Reference design values for structural timber to both the US National Design Specification (NDS) and Eurocode 5 (EN 338 / EN 14080). Values are shown before adjustment factors - apply the NDS C-factors or EC5 k_mod and γ_M for your load case.
Dimensional Lumber
Reference design values for visually-graded sawn softwood - Douglas Fir-Larch, Hem-Fir, Spruce-Pine-Fir and Southern Pine (NDS), plus EN 338 strength classes (EC5).
17 grades to NDS 2018 Supplement (Tables 4A, 4B) / EN 338:2016
Glued-Laminated Timber
Reference design values for structural glulam - NDS bending combinations (24F-V4, 24F-V8, ...) and EN 14080 strength classes (GL24h-GL32h, GL24c-GL28c).
9 grades to NDS 2018 Supplement Table 5A / EN 14080:2013
Engineered Wood (LVL / PSL / I-joist)
Laminated veneer lumber (LVL), parallel strand lumber (PSL) and wood I-joists. Values are product-specific - the figures shown are representative; use the supplier's evaluation report for design.
4 grades to Manufacturer ICC-ES / APA evaluation reports
Cross-Laminated Timber (CLT)
Mass-timber CLT panels - PRG 320 grades (E1-E4, V1-V3) and EN 16351 layups. Panel capacity depends on the specific layup; the values shown are the lamination basis - use panel tables or the shear-analogy method for design.
4 grades to ANSI/APA PRG 320 / EN 16351