Designing stairs is more intricate task than many people realize. And it’s not just about how the stairs look. Proper proportioning is critical to comfort and safety. Set the tread and riser sizes carefully. For  I recommend 10″ treads with a one inch nosing. The nosing is the projection forward of the tread beyond the riser below. The riser is the vertical portion of the step. I try to keep the riser height under 7 1/2“, preferring to end up with about 7 1/4″ if I can. We’re all getting a bit older and the fraction of an inch can really make a difference in how a staircase feels. On a house with the now fairly common ten foot ceilings, 18 risers will give you risers of about 7 1/3″. If you have a situation where you want to further reduce the riser height to fit a particular situation or if you have bad knees, you can go by the old “Rule of Thumb” that said the riser and tread dimensions, when added together, should equal 17.  So 6 1/2″ risers would be combined with 10 1/2″ treads for maximum comfort. But there are always exceptions to Rules of Thumb, of course. (more…)