Short answer: a pergola wind or snow rating is only valid for a specific size, configuration (louvres open or closed, screens fitted or not) and foundation. Ask for the rating for your exact size and site, check it against the design wind speed and snow load required by your local code, and get it in writing on the quotation or drawing.
What a rating depends on
- Span and module size — a 3 × 3 m module and a 4 × 6 m module on the same profiles do not have the same capacity.
- Beam and post sections — wall thickness and profile depth drive stiffness.
- Louvre position — closed louvres act like a solid roof; open louvres let wind pass.
- Side screens and glass — closing the sides turns the pergola into a box and raises wind load considerably.
- Foundation and anchors — the structure is only as strong as its base plates, bolts and footings.
- Site exposure — coastal, rooftop and open-country sites see higher wind than sheltered gardens.
km/h and the Beaufort scale
Brochures quote km/h, installers often think in Beaufort, and building codes use design wind speeds or pressures. A quick reference:
| Beaufort | Description | Wind speed (km/h) |
|---|---|---|
| 6 | Strong breeze | 39–49 |
| 7 | Near gale | 50–61 |
| 8 | Gale | 62–74 |
| 9 | Strong gale | 75–88 |
| 10 | Storm | 89–102 |
| 11 | Violent storm | 103–117 |
| 12 | Hurricane force | 118 and above |
Note that gusts are higher than mean wind speed, and building codes specify a design wind speed for the location, height and terrain — that, not the brochure figure, is what an engineer will check.
Snow load in kN/m²
Snow load is given as force per area, usually in kN/m² (1 kN/m² is roughly 100 kg of snow on every square metre). Ground snow load varies widely by region and altitude, so the required roof load comes from the local code map. For louvred roofs, check whether the rating assumes louvres closed, and follow the manufacturer's instruction for positioning blades during snowfall.
Standards by market
| Market | Wind | Snow |
|---|---|---|
| EU / UK | EN 1991-1-4 (Eurocode 1, wind actions) with the national annex | EN 1991-1-3 (snow loads) |
| USA | ASCE 7, as adopted by the local building code | ASCE 7 |
| Australia / NZ | AS/NZS 1170.2 | AS/NZS 1170.3 |
Retractable awnings in Europe are classed for wind resistance under EN 13561 (classes 0–3). Louvred pergolas are usually assessed as structures against the codes above. Whether a permit and engineer's calculation is needed depends on local rules — always check before installation.
Operating wind vs survival wind
Two different numbers are often mixed up. The operating limit is the wind speed up to which the louvres can safely be moved by the motor. The structural (survival) rating is the wind the fixed structure is designed to withstand in a given position. A wind sensor normally acts on the operating limit — it does not make the structure stronger.
What to ask your supplier
- The wind and snow rating for the exact module size, with louvres open and closed
- Whether the rating changes when ZIP screens or glass are fitted
- The calculation basis or test report, and which standard it refers to
- Base plate size, anchor bolt specification and recommended footing
- Recommended post spacing or extra posts for exposed sites
These points sit alongside the other specs in our 10-point buying guide.
FAQ
What wind speed can a louvered pergola withstand?
It depends on the size, profiles, louvre position, screens and foundation. Brochure figures apply to a tested configuration — ask for the rating for your exact size.
Should louvres be open or closed in strong wind?
Follow the manufacturer's instruction for that system. Many recommend a specific position for high wind; screens should normally be retracted.
How much snow can a pergola hold?
Snow capacity is stated in kN/m² for a given span. Compare it with the snow load your local code requires for the site.
Need a rating for your size?
Send the dimensions, site location and screen options and we will confirm the configuration on the drawing. Product specs: louvered pergola specifications.