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Timber Beam Design Calculator

Solid-sawn or glued-laminated timber beam design to EN 1995-1-1 (EC5), with a SANS 10160-1 load option. Simply-supported or cantilever: live bending with lateral-torsional stability, shear parallel to grain, bearing (compression perpendicular to grain), and instantaneous plus final creep deflection — with load-duration, service-class and creep (kmod / kdef) modification factors, a beam diagram and a printable clause-by-clause calc sheet. All characteristic grade stresses are editable user inputs.

EC5 clause-by-clause engine · characteristic grade stresses are user inputs — verify against SANS 10163-1 / SANS 1783-2 or EN 338

Inputs

Member
m
Load-combination code
Section (rectangular)
mm
mm
Applied line loads (characteristic)
kN/m
kN/m
kN/m
Wind sign convention — + positive = DOWNWARD ↓ (pressure onto the beam, same direction as gravity). − negative = UPWARD ↑ (uplift / suction, opposite to gravity). Enter 0 for no wind.
Point load (optional, adds to the UDL)
kN
kN
kN
m
M, V and deflection are superposed as independent peaks (UDL peak + point-load peak) — a closed-form, slightly conservative combination when P is not at the UDL's own peak location.
Load partial factors set by code — editable
Characteristic propertiesDEFAULT — VERIFY against SANS 10163-1 Table / SANS 1783-2 (or EN 338). Published SA grade stresses vary by edition — confirm the exact table row.
MPa
MPa
MPa
MPa
MPa
MPa
kg/m³
Modification & partial factors
Lateral-torsional buckling — SAGGING (compression edge = TOP)used by any combination whose Md is positive (downward net load)
m
mm
Lateral-torsional buckling — UPLIFT / REVERSAL (compression edge = BOTTOM)Sheeting normally restrains the TOP face only. Under uplift the compression edge is the BOTTOM one and is usually UNRESTRAINED — the defaults below assume exactly that. Change them only if the bottom edge really is braced.
m
mm
Bearing & deflection limits
mm
mm
mm

Beam & section

Loading & span
Section b × h

Design result

—
—
enter loads
Design load wd—
Design moment Md—
Design shear / reaction Vd=Rd—
Bending strength fm,d—
LTB factor kcrit—
Shear strength fv,d—
Bearing strength kc,90·fc,90,d—
Governing check—
Governing combination—
Section A—
Wy / Iy—
Compression edge (governing)—
Net uplift reaction Rup—
kmod / kh—
Eff. length lef—
λrel,m—
uinst (limit)—
ufin (limit)—
Governing utilisation—

Load combinations

Design checks

Step-by-step calculation

Combined timber take-off — all members

Every member in the project, aggregated into a material take-off. Length uses the span L; volume = b × h × L; mass = volume × ρmean. Use “Add member” above to build the list, then Download PDF (print → Save as PDF).
EC5

This isn't a toy calculator

It runs the same engine as STATIX — a full structural suite validated against closed-form and code benchmarks across analysis, design and connections — the full 3D modeller with native CBFEM is coming soon. Model the whole frame, not just one member.

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