CLT Grade E2 (PRG 320) - Design Values
CLT Grade E2 (PRG 320) is a cross-laminated timber (clt) grade with reference design values to ANSI/APA PRG 320. Its reference bending value Fb is 1,650 psi, compression parallel Fc is 1,700 psi, and modulus of elasticity E is 1,500,000 psi (NDS). Values are shown before adjustment factors; apply the relevant NDS C-factors or EC5 k_mod and γ_M for your load case.
Representative values. E2 major-direction laminations are 1650f-1.5E MSR Douglas Fir-Larch. Panel capacity depends on the layup - use PRG 320 panel tables for design.
| Fb | Bending | 1,650 psi |
| Ft | Tension parallel | 1,020 psi |
| Fv | Shear parallel | 180 psi |
| Fc⊥ | Compression perpendicular | 625 psi |
| Fc | Compression parallel | 1,700 psi |
| E | Modulus of elasticity | 1,500,000 psi |
| Emin | Modulus for stability | 550,000 psi |
Source: ANSI/APA PRG 320. Reference values are shown before adjustment factors (NDS C-factors / EC5 k_mod, γ_M) - apply these per your load case in design.
Understanding these values
For a beam in CLT Grade E2 (PRG 320), bending at Fb 1,650 psi normally sets the size, but the check that actually governs depends on the span. Short heavily loaded members are often limited by shear at Fv 180 psi, and bearing at a support is limited by compression perpendicular to grain at Fc perp 625 psi, which is the lowest of the strength values and the one most often overlooked. Used as a post or stud, the governing value is compression parallel at Fc 1,700 psi.
Stiffness for CLT Grade E2 (PRG 320) is E 1,500,000 psi, with the reduced modulus Emin 550,000 psi used for stability calculations such as the beam stability factor CL and the column stability factor CP. On typical floor spans, deflection rather than strength decides the section, so compare E before Fb when the member is a joist.
Within the cross-laminated timber (clt) entries in this catalogue, CLT Grade E2 (PRG 320) ranks 2 of 3 on bending at 1,650 psi; the strongest listed is CLT Grade E1 (PRG 320) at 1,950 psi. Grade choice is usually a trade of cost against section depth, so it is worth checking whether a lower grade in a deeper section is cheaper than a higher grade at the depth you started with.
The closest alternative in the same family is CLT Grade E1 (PRG 320) at 1,950 psi in bending, 15% above this grade. If availability drives the choice rather than capacity, that is the substitution to price first - but re-run the deflection check as well, because stiffness and strength do not always move together.
The CLT Grade E2 (PRG 320) figures above are representative of cross-laminated timber rather than of any one manufacturer's product. cross-laminated timber is proprietary: published design values differ between suppliers, and for CLT they also depend on the layup and the panel thickness you actually specify. Use this page for scheme design and take the specific product's evaluation report for the final check.