The Maximum Angle For Stair Risers - Building Code Education
The maximum riser angle for stairs is the steepest angle that the stairs can be without being considered unsafe. This angle is determined by building codes, which are sets of rules that regulate the construction of buildings.
The maximum riser angle for stairs varies depending on the type of building, the location of the stairs, and the intended use of the stairs. However, there are some general building codes that apply to all types of stairs.
What are the general building codes for maximum riser angle?
The International Building Code has a 30 degree maximum riser angle. (R311.7.5.1 Risers)
However, these are just recommendations. Building codes may allow for steeper riser angles in certain situations, such as when the stairs are used for commercial purposes or when the stairs are located in a multi-family dwelling.
Calculating Stair Riser Angles with a Speed Square
A speed square is a versatile tool that can be incredibly handy for stair building, especially when it comes to determining riser angles. This guide provides a simple, step-by-step approach to using a speed square for this task, making your DIY stair project easier and more accurate.
What You'll Need:
Speed Square: A standard speed square with degree markings.
Level: To ensure your measurements are accurate.
Pencil: To mark your measurements.
Step-by-Step Instructions:
Hold the speed square vertically against the riser board.
Ensure the pivot point of the speed square is aligned with the edge of the tread.
Align for the Run:
On the side of the speed square with common rafter tables, locate the inch mark that corresponds to your "run" measurement.
Rotate the speed square until this mark aligns with the edge of the tread board.
Read the Riser Angle:
Look at the degree markings on the speed square. The degree mark that intersects with the top edge of the tread board is your riser angle.
Advantages of Using a Speed Square:
Quick and Easy: Provides a fast and straightforward method for determining riser angles.
Portable and Versatile: A compact tool that's easy to carry and use on-site.
Multiple Functions: Beyond calculating angles, a speed square can be used for various other carpentry tasks, making it a valuable tool for any DIYer.
