Volex Labs / Calculations / Snow loading to EN 1991-1-3, UK zones and altitude.

Snow loading to EN 1991-1-3, UK zones and altitude.

Pick the UK snow zone and altitude and Volex Anvil computes the characteristic ground snow load sk from the UK NA equation, applies the roof shape factors (mono-pitch, duo-pitch, flat), and reports the roof snow load ready for your load combinations — including the drift cases that catch people out at parapets and steps.

The zone/altitude arithmetic is validated against the UK National Annex directly (Eq NA.1 and Figure NA.1), from SE England at sea level to the Scottish zones.

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Free account · 10 calculations/month · no card required · Pro £29/month

What Volex Anvil checks

Validated against the published example

Snow Zone 1 (SE England) at 100 m altitude BS EN 1991-1-3 UK NA Eq NA.1; Cook & Pendlebury
QuantityPublishedVolex AnvilError
sk0.524 kN/m²0.524 kN/m²0.00%
This case is one of 365 published checks the platform passes — the full table, with every source and every error, is public at volexlabs.com/verification.

Frequently asked

Does it cover the UK snow zones?
Yes — all UK NA zones with the altitude correction of Eq NA.1, validated from Zone 1 at sea level through Zone 4 in western Scotland.
Does it handle drift loading?
Yes — the Annex B drift cases at steps, parapets and obstructions, which is usually the governing case on extensions and podium decks.
Can the result feed a rafter design?
Directly — snow output plugs into the EC5 rafter module and the EN 1990 load combination generator.
How much does it cost?
Free for 10 calculations a month; £29/month for unlimited use and PDF calc sheets.

Related calculations

Wind loading to EN 1991-1-4, with the UK National AnnexTimber beam design to Eurocode 5Steel beam design to Eurocode 3, in your browser

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