Free Tool · EN 1991-1-3:2003 · No Sign-up

EN 1991-1-3 Snow Load Calculator

Compute s_k characteristic ground snow, roof shape coefficients μ_i, exposure C_e, thermal C_t, and design roof snow load s = μ_i · C_e · C_t · s_k per EN 1991-1-3:2003. Mono, duo (balanced + drifted), multi-span valley, drift against taller wall. NL/DE/UK/FR/SE NAs. No sign-up.

Site & Country

National Annex / country

Snow zone

Site altitude (m a.s.l.)

Roof Geometry

Roof type

Roof pitch α (°)

Coefficients

Exposure (Table 5.1)

Thermal coefficient C_t

EN recommended: use Annex C eq. C.1 (quadratic altitude correction). Select zone and altitude.

s_k,0 (kN/m²)

0.56kN/m²

s_k (kN/m²)

0.56kN/m²

μ₁

0.8

C_e / C_t

1 / 1

Design s_max

0.448 kN/m²

s = μ₁ · C_e · C_t · s_k (EN 1991-1-3 eq. 5.1)

Step-by-step

1. s_k,0 (sea level, zone NL1)	0.56 kN/m²
2. Altitude correction (A = 0 m)	→ s_k = 0.56 kN/m²
3. C_e (exposure)	1
4. C_t (thermal)	1
5. μ₁ (Table 5.2, α = 30°)	0.8
6. s = μ·C_e·C_t·s_k	0.448 kN/m²

Load Cases (Duopitch)

Case	μ slope 1	μ slope 2	s slope 1 (kN/m²)	s slope 2 (kN/m²)
Undrifted (balanced)	0.8	0.8	0.448	0.448
Drifted I	0.4	0.8	0.224	0.448
Drifted II	0.8	0.4	0.448	0.224

ψ factors

ψ₀=0.5 ψ₁=0.2 ψ₂=0

Indicative values. Verify s_k against official NA zone maps for permit drawings.

Export calculation report

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