Spiral Staircase Risers

A riser affects a lot of aspects of a stair. It’s part of calculating the number of steps needed and the overall height of the stair; you take into account the run (horizontal step/plane) and rise (vertical space/piece between steps). This calculation is very different for straight and spiral stairs, but the element of risers is still taken under consideration for both.

There are also safety and aesthetic implications that a riser piece (or comparative lack thereof) can make for a spiral stair. So mulling over just what you want your risers to accomplish for you and your stair is worth some brief reflection.

One immediate fact worth noting and memorizing when it comes to the application of spiral staircase risers is that the space between a riser piece and the step below it can be no greater than 4” if the spiral stair is to satisfy code needs.

The simple test for this is to attempt to pass a 4” diameter ball between the riser and the step. If it can’t fit, then the stair meets code. If it passes right through, the stair does not meet code.

Keep in mind that meeting or not meeting code has nothing to do with the quality of the stair. In fact, meeting code is rarely a requirement. Unless the stair is for a commercial, business, or other public application, odds are it’s not something you have to worry about. Make sure to check with your local building authority before assuming, though.

Another code factor involving the rise of a stair is that each step cannot rise more than 9 1/2″ above the step below it. That’s a measured height from the top of one step to the top of the step above it.

Remembering these two points will make sure you’re able to meet code as far as your risers go if that’s a requirement for you.

A primary factor that may influence your decision to not build using code risers if your building authority doesn’t require it is that of style preference. The two extremes of style preference directly affected by risers if whether you want your stair to have an “open” or “closed” look.

Part of the allure of a spiral stair is its hyper modern appeal and its minimalist approach to accomplishing the egress needed. Some may choose to emphasize this minimalist by having much narrower riser pieces (and therefore greater gaps between the riser pieces and the step below) or no riser piece at all. This is up to the owner of the stair. Just keep in mind the implication of allowing the riser space to be large enough for your foot to fit through.

The riser piece itself can also act as a canvas. The line at the bottom can be curved various ways or razor straight. And the shape of that line has a subtle influence on the overall theme of your stair.

Besides the actual outline of the riser piece, there are also numerous options for designs that can be cut into the piece. One of the beauties of cutouts like this is that they make it possible to have that desirable open look while still meeting code. So long as the bottom of the riser with the cutouts is low enough to create that 4” gap, you satisfy code.

Knowing these elements and their influence on your stair’s cost will let you move that much closer to making the best decision for your needs.