Beyond any doubt, if there’s any part of a landscaping job that’s poorly done, it will be the steps. Maybe it’s because gardeners and designers tend to design in plan view rather than elevation, so they don’t really see what’s needed until it’s under construction. Whatever the reason, unless you’re dealing with a site that’s as flat as a pancake, steps are a critical part of garden making.
The old rule of twice the riser height plus the stair tread length (or ‘going’) should equal between 650-680mm (25-27″) is still the best design strategy. That means a riser height of 150mm (6″) should have a tread of around 350-380mm. No more, and no less. If you need steeper stairs, say up to 200mm, then you need shorter treads of 190mm. On winding stairs, calculate tread length in the centre of the step.
If you break this rule, then people will find your stairs difficult to use, either requiring an extra walking step per stair, or picking up too much speed going down a steep flight. You should also be looking to add a landing at least every 11th stair if you possibly can.
Calculate your level change carefully so you don’t end up with one step that’s much taller or shorter than the rest. It’s the worst stair mistake of them all, and probably the most common. And avoid single steps if possible, as people are quite likely not to notice them and to trip up or down them, unless there’s a very clear change of surface.
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That’s a very intereting formula there Catherine …. hadn’t heard of that one before ….. VERY useful information on Garden Drum always … the best on line garden read by far !
Hi. i have a question, i agree with you when you say there is no information about step designing. I know about the Blondel rule, but i want to know what is the recomendation if i want a longer “going”, for example 80cm or 1m.
Hi Sebastian – if you’re going to have longer steps, then I think that there are two rules to follow.
Rule 1 is to keep a minimum step height of 120mm, otherwise the step becomes a trip hazard as it’s not clearly defined. I would also have a contrasting band on the edge of each step so it’s eay to see.
Rule 2 is to have the tread (or ‘going’) long enough for two intermediate walking strides, so that you change foot with each step up/down. Otherwise you get that alwful rhythm of always stepping up (or down) on the same foot. Allowing around 500mm for each for the 2 intermediate walking steps (a normal gait on flat ground is probably a 600mm but when walking up and down stairs, I’m thinking the average stride would be shorter), and about 300mm for where you place your foot as you first step up, you would need a going of about 1300mm to change feet each time.