Snow load 1.0 kN/m², wind speeds 24 and 27 m/s and roof shape factors — the specific figures from the DS/EN 1991 series that determine what your rafters and beams must carry.
Introduction
When the designing engineer calculates what a rafter structure should handle they set loads from self-weight (the weight of the structure itself and the roof) live load snow and wind. The Eurocode 1 series with the Danish national annexes establishes how these loads are calculated.
Snow load
Den karakteristiske grundværdi for snelast i Danmark er s_k = 1,0 kN/m² på vandret underlag (hele Danmark). Det er den eneste zone i Danmark — DS/EN 1991-1-3 DK NA:2024 opererer ikke med regionale snezoner herhjemme.
Et saddeltag på 20° med C_e = C_t = 1,0 giver s = 0,8 · 1,0 · 1,0 · 1,0 = 0,8 kN/m². Tagformfaktoren og dens afhængighed af taghældning er tabelleret i EC1-1-3.
Wind load
Vindlastens grundhastighed er v_b,0 = 24 m/s i det meste af Danmark. I kystzone (nærmere end 25 km fra Vesterhavet og Ringkøbing Fjord) er grundhastigheden 27 m/s. Det svarer til en ekstra last på ca. 27 % i de udsatte kystområder.
Self-weight — indicative values
The self-weight depends on the specific roof. As an indicative order of magnitude: light roof (sheathing + zinc plates/steel) approximately 0.30 kN/m², heavy tile roof approximately 0.90 kN/m². The actual self-weight is always determined per project based on selected materials.
| Load type | Characteristic value | Standard |
|---|---|---|
| Snow load, basic value (DK) | s_k = 1,0 kN/m² | DS/EN 1991-1-3 DK NA:2024 |
| Tagformfaktor, enkeltfald og saddeltag ≤ 30° | µ_i = 0,8 | EC1-1-3 |
| Basic wind speed (inland) | v_b,0 = 24 m/s | DS/EN 1991-1-4 DK NA:2024 |
| Basic wind speed (coastal zone) | v_b,0 = 27 m/s | DS/EN 1991-1-4 DK NA:2024 |
| Light roof (guideline dead load) | ~0,30 kN/m² | Indicative |
| Heavy tile roof (indicative dead load) | ~0,90 kN/m² | Indicative |
Members only
The rest of the article is locked
Create a free user account to unlock all articles, calculators, templates and range — and get access to quizzes and classes. It takes less than a minute: name, email and a password. No payment card.
Want to try something first? See what you can use without an account — the junior zone, the encyclopedia, the videos and more.