Wood Member Design

Size joists, rafters, beams, and built-up columns in Southern Yellow Pine, LVL, and glulam. Design finds the lightest passing member; Analysis checks a member you specify.

Project

Project name

Choose a folder and file name when saving. Projects are stored as .json files you can share or back up.

Use the File menu to open, save, or start a new project.

Design / Analysis

Design searches the catalog for the lightest passing member. Analysis checks the size you select below.

Member & application

Member type

Application

Material / grade Joist/Rafter: single-ply dimensional lumber only (SYP).

Member size Required in Analysis mode.

Size constraints

Max depth / height in.

Max width in.

Optional. Depth = dressed member depth; width = total built-up width (b × plies). Beams/Columns: 1–4 ply built-up. Joists/Rafters: single ply.

C_M wet service (NDS Table 11.3.1)

F_b	F_v	F_c⊥	E
—	—	—	—

C_M bearing applies to Fc⊥ checks on the Results tab.

Other adjustment factors

C_r	C_L	C_F
—	—	—

C_t = 1.0 and C_i = 1.0 assumed for all members.

Column stability (NDS 3.7.1 · K = 1.0)

ℓ_e	ℓ_e/d	ℓ_e/(b×n)	C_p
—	—	—	—

ℓ_e = K × unbraced height (K = 1.0 pin-pin assumed). C_p governs by the weaker buckling axis. Limit ℓ_e/d ≤ 50 (NDS 3.7.1.5).

Reference design values (2018 NDS — verify / supplier)

Member	—
F_b	—	F_v	—
F_c	—	E	—

All values in psi.

Wet-service C_M defaults follow 2018 NDS Table 11.3.1 when exterior application is selected. C_r, C_L, and C_F are assigned automatically by member type and catalog. C_D is assigned automatically per ASD load combination (2018 IBC §1605.3.1 / IRC R301.5; 2018 NDS Table 3.1.2). SYP dimensional F_b, F_v, F_c, and E are size-specific tabulated values (2018 NDS Supplement Table 4A).

Results update automatically when inputs change.

Member —

Governing check —

Unity ratios & deflection

Check	Actual	Allowable	Unity	Δ (in.)	L/Δ (limit)

Calculation detail