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Alternating Tread Stairs

Ever heard of “alternating tread stairs”? Until yesterday, I had not. They aren’t exactly common in the United States, probably due to the fact that they don’t meet the strict code requirements that most municipalities impose on stair construction. Whether or not the design of these stairs meets code in your area is determined by the local officials. (In some rural areas of my home state of Alabama, the only code official is the septic tank inspector.) Nevertheless, I thought this was a cool take on stair design, which significantly economizes space, and thought it would interest readers of EHT.

According to Wikipedia, alternating treads “are designed such that they alternate between treads for each foot: one step is wide on the left side; the next step is wide on the right side. There is insufficient space on the narrow portion of the step for the other foot to stand, hence the person must always use the correct foot on the correct step.”

The slope of the alternating treads can be as high as 65 degrees, whereas standard stairs are almost always less than 45 degrees and occupy much more space. And, unlike a ladder, which is the only other alternative that will fit in such a narrow space, the alternating stairs allow people to walk up and down facing forward, as opposed to backward.

It turns out that our friends at Arke Stairs even sell a kit for constructing a set. Here’s a photo of the Arke Karina staircase kit after assembly:

arke karina

The graphic below, courtesy of Arke Stairs, illustrates how the overlapping, alternating treads grant full stair access from one level to another in a much smaller horizontal footprint than a standard staircase:

arke karina2

Alternating stairs can also be custom-built by an experienced carpenter. Check out this blog post at Bottleworld.net about a homeowner who utilized a set of carpenter-built alternating stairs to save space in his “tiny house project”.

– M. Weber

2 comments

  1. Robb Gillion says:

    The Arke Karina staircase kit is the ideal stair to use when completing an attic renovation project.

    In today’s economic times and with the difficult employment conditions that exists, many families have seen their children graduate from college and take their own first steps into the “real” world only to find their “empty nests” filled back up again with their adult children moving back home. The children’s bedrooms that had become the family’s new office space or sewing room now are now needed for actual bedrooms again.

    The attic is sometimes the only available, and often under-utilized remaining space available to recapture the former office or “extra room” they previously enjoyed. In the majority of cases, the attic is accessed by a pull-down attic ladder that has a very small opening in the ceiling. The standard opening size is 25″ wide x 42″ long.

    The Karina staircase kit by Arke can be installed in a straight line run to fit into as narrow a width as 25″ side-to-side and the homeowner would only have to increase the length of the opening to approximately 60″ for the staircase kit to be installed and allow plenty of headroom space to comfortably walk up or down the stairs without bumping your head on the ceiling or opening.

    The installation is truly a DIY project and can be completed in as little as 1 day.

    Having personally installed one of these staircases, and possessing very limited skills in home repair/renovation projects, I found it to be easy to complete and am very pleased with the quality of the product.

    I now have my own “man cave” back!!!

  2. Matt Weber says:

    Great information, Rob. I want a man-cave of my own.

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