No, a marquee is far more wind resistant with the sides on rather than off. For some reason there are many people who believe that leaving the sides off a marquee ‘lets the wind pass through’. I will try to explain below why this is not true and why leaving the sides off of a marquee actually makes it far more susceptible to the wind than leaving the sides on.
The diagram above shows how the wind passes over a marquee and how any wind going in to the marquee gathers and lifts the roof up. The best way to avoid this is simply to have the sides on the marquee facing the wind and have the marquee well anchored down.
Please note that this article is dealing with marquees in strong winds but not extreme weather. Marquees should not be left erected in extreme weather conditions.
The people who advocate taking the sides off in strong winds believe that the above scenario is best solved by removing the remaining side panels, thus allowing the wind to pass harmlessly through the other side of the marquee. It doesn’t. There are two factors in play if the sides are off.
i. Wind building up under the marquee roof – this still happens even if that other side is taken off. Don’t believe me? Try walking across a field in windy conditions with an umbrella – by taking the sides off your marquee you’re turning it in to one very large umbrella.
ii. Lift being created by the wind that DOES pass through the marquee:
This shows the wind passing over or through the roof only marquee. The wind passing over the top of the marquee has much further to travel so has to go faster to keep up. This may ring some bells for those who stayed awake during Physics lessons:
A marquee roof isn’t as aerodynamic as a wing but a lifting force will still be created, not only that but the steeper the roof the more force there will be – another reason for having a 20degree roof/3m apex on 6m marquees as discussed last week.
This post isn’t intended as scare-mongering, it is purely aimed at dispelling a myth. At DIY Marquees we try to encourage all of the marquee hire companies we help to follow best practices:
- Ensure the marquees are well anchored down, that means tie down kits as a minimum.
- Leave the walls on any side likely to face strong winds (have the entrance on a different side)
- Never take all of the sides off a marquee in strong winds
- Know your marquees limitations -if Michael Fish states there definitely won’t be a hurricane then resign yourself that the marquee has to come down (this is rare, it happened once in the 10+ years I ran a hire business).
Thanks for reading, as always feedback is gratefully received.