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 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.

Run this calculation free → See the verification
Free account · 10 calculations/month · no card required · Pro £29/month

What Volex 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
QuantityPublishedVolexError
sk0.524 kN/m²0.524 kN/m²0.00%
This case is one of 359 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

Check it in the code, not in a black box.

Every result carries its clause references. Free tier, results in seconds.

Try Volex free →