Installation Guide
Mylen Code Stair Packages will address and meet compliancy with 
each of the requirements that are listed below. This information will 
apply to the BOCA Code, UBC Code, IRC, and IFC codes. 
1.  Minimum clear walking path of 26 inches. A 5-foot diameter or larger 
stair will provide this width. 
2.  Each tread will have a minimum of 7 1/2-inch tread depth at 12 inches 
from the narrow edge. 
3.  All Treads will be identical. 
4.  The tread rise shall not be more than 9 ½ inches high. 
5.  Minimum headroom of 6 foot 6 inches shall be provided, measuring 
plumb from the edge of the platform down to the tread below 
6.  Landing width shall not be less than the required width of the stairway. 
Minimum spiral stair tread width is 26 inches. 
7.  Stair balusters shall be spaced so a 4-inch object cannot pass between. 
The IRC Code permits a 4 3/8-inch space. 
8.  Balcony / well enclosure guardrail balusters shall be spaced so a 4-inch 
object cannot pass between. 
9.  Balcony / well enclosure guardrail height shall not be less than 36 
inches. (If your state or municipality requires 42-inch tall guardrails, the 
sales order must reflect this detail). 
10.  The stairway shall be equipped with one handrail on the wide edge of 
the tread. 
11.  Handrail height, measured vertically from the tread nosing, shall not be 
less than 34 inches and not more than 38 inches. 
12.  Handrail grip size. Type I-Handrails with a circular cross section shall 
have an outside diameter of at least 1 1/4 inches and not greater than 2 
inches. (Mylen’s standard circular handrail is 1 1/2 inch diameter. This 
will address the UBC minimum cross section of 1 1/2 inch diameter.)  
13.  A 300 lb. concentrated load is required. On request, our sales 
department can provide structural calculations for your job 
specifications. 
*Mylen’s standard code package does not address the open space between 
each tread (open rise stair). If your local building code requires no more 
than 4” space in this area, please call (855) 869-8594 to have riser bars 
included in your order or speak with our customer support team for other 
options. 
   BUILDING CODE SPECIFICATIONS 
Visual Interpretation of IRC Code 
Mylen Spiral Stairs Comply with National Building Codes 
R311.5.8.1 Spiral Stairs. Spiral stairways are permitted, provided the 
minimum width shall be 26 inches (660 mm) with each tread having a 7 
1⁄2 inch (190 mm) minimum tread depth at 12 inches from the narrower 
edge. All treads shall be identical, and the rise shall be no more than 9 1⁄2 
inches (241 mm). A minimum headroom of 6 feet, 6 inches (1982 mm) 
shall be provided (See above diagram).  
Visit mylenstairs.com for more information or call (855) 869-8594 to speak with a 
customer or product support member. 
Handrail 
Height 
(34” Min. to 
Max. 38”)
9 ½” Max. 
Rise 
Max. 4” 
Sphere 
Min. 
Headroom 
6’6” 
Min. 36” 
Platform Rail 
Height 
*4” Max. 
Open Space 




