Open stair tread design is very beautiful. They give the appearance of the stair floating. They give a light and airy feeling to a sometimes forgotten design element. Do you want an open stair tread in your design? Their are specific requirements for how large the tread needs to be, the minimum and maximum height between treads. Some of the most beautiful stairs have open stair treads. Can you use them in your next project?
Building codes sections about stairs are very lengthy. They go into detail about length and width of treads, where handrails are needed etc. The code is very clear when open stair treads are allowed . Per IBC 1011.5.5.3, Solid Risers “Risers shall be solid“. Their are a few exceptions to open stair treads.
In residential applications, you will see the majority of the open risers stairs. Some defy gravity and cantilever off the walls. They can be a work of art within a space. This is why, architects push the design envelope in residential design when designing stairs. The IRC, Section R3188.8.131.52, specifically states “At open risers, openings located more than 30 inches, as measured vertically, to the floor or grade below shall not permit the passage of a 4 inch diameter sphere. (Interpretation – Open treads allowable anywhere in a residence as long as their is not an opening greater than 4″).
Open stair treads can add a beautiful element to any architectural design. Can you use this design element? Current code does not allow it in some commercial applications. They are not allowed as a required exit in a commercial project. They are allowed in occupancies such as Industrial, factories, storage facilities and hazardous occupancies. Use them in any of your residential projects. As with all projects, Check with your local jurisdiction to ensure your projects success. As with all design elements, their are exceptions to the rules.