Over the last few months, we have seen a lot of poorly built stairs. The risers are too tall or too short, or the treads too shallow. Occasionally, the “nosing,” or solid part of the tread hanging over the next step down, is too large.
Stairs must be built to precise, closely guarded specifications. Codes aim to protect adults and children from falling down them. The precision required is meant to make stairs as safe as possible.
Essentially, any time a riser is taller than 7 3/4″ or a tread is not at least 10″ deep, excluding the nosing depth, the stairs are unsafe. Either condition makes the stairs effectively too steep, particularly when traveling down.
Stairs feel too steep going down because normal-to-large sized feet must “hurry” to get to the next step. Humans are built to carry weight around the mid-section and balance on the balls of our feet. Shallow treads and tall risers force faster downward strides, giving the feeling of falling. Thus, even when we don’t fall down poorly built stairs, they tend to worry us.
Overall, watch out for poorly built stairs, and rebuild the ones that are.