Product Details - Exterior Grade Stairs Example

The following are a number of examples of ways to use Ply-Lam for exterior grade stairs.  While some dimensions are provided as guidelines, these examples are not intended as a complete engineered design.  Please ensure that you always follow appropriate engineering rules and building code guidelines when constructing stairs.



The below diagram and chart shows engineered Unsupported Stringer Lengths for PT Ply-Lam as an Eastern (or Cut-Out) Stringer.

In the below diagram and chart, the Thickness (W) and Effective Depth (ED) of the stringer are adjusted based on the required unsupported length.  



The chart below uses the above indices and shows the Alberta Building Code Permitted Unsupported Length. All measurements are given in Inches:


Product Code


   (Width - W)   

Effective Depth 


    AB Code Permitted Unsupported Length   

PT PL4 C 4.625    1.5 4.625

80 (We recommend a maximum of 6 steps)

PT PL4 C 8.625    1.5 8.625

148 (We recommend a maximum of 11 steps)

PT PL8 C 4.625  3 4.625

101 (We recommend a maximum of 8 steps)

PT PL8 C 8.625  3 8.625

188 (We recommend a maximum of 15 steps)