Stairs are an essential part of a building, providing safe and easy access between different floors. But have you ever wondered about the process behind designing and building stairs? One of the most critical components in this process is calculating the stair stringers, which serve as the backbone of the entire staircase structure. In this article, we’ll guide you through the step-by-step process of calculating stair stringers, ensuring a sturdy and well-designed staircase.

Step 1: Gather required information

Before you begin calculating your stair stringers, you’ll need to gather the following measurements:

– Total vertical height (rise): Measure the total vertical distance between the lower and upper floors.

– Horizontal distance (run): Measure the horizontal distance available for constructing your stairs. This measurement will sometimes be predetermined by space constraints.

– Desired tread depth (d): Choose how deep each step will be, based on safety and comfort considerations.

– Desired riser height (h): Choose how high each step will be, based on safety and comfort considerations.

Step 2: Determine the number of risers

Using your desired riser height (h), divide the total rise by h to find out how many steps you’ll need. Round up or down depending on the exact number obtained.

Total risers = Total rise ÷ Desired riser height (round up or down)

Step 3: Adjust actual riser height

You may need to adjust your actual riser height based on your rounded number of risers. This calculation ensures that all steps are evenly distributed throughout the vertical rise.

Actual riser height = Total rise ÷ Number of total risers (round to two decimal places)

Step 4: Calculate number of treads

Subtract one from the number of total risers to get the number of treads.

Total treads = Total risers – 1

Step 5: Calculate actual tread depth

Determine the actual depth of each step by dividing the total run by the number of treads.

Actual tread depth = Total run ÷ Total treads (round to two decimal places)

Step 6: Calculate stringer length

Using the Pythagorean theorem, calculate the stair stringer’s overall length:

Stringer length = √[(Actual tread depth^2) + (Actual riser height^2)] × Number of total treads

Step 7: Determine the notches and angles

Sketch out the stair stringer on a piece of plywood or other material. Using a framing square, draw out your notches for each tread and riser, based on your calculated dimensions. Be sure to include any necessary allowances for finishing materials or nosing that may be used on your staircase.

Step 8: Cut and install stringers

Once you have drawn out your stringers, carefully cut along your layout lines using a circular saw or jigsaw. Be sure to make accurate cuts to ensure proper step placement. After both stringers are cut and prepared, install them at equal distances to support the treads and risers.

By following these steps, you can calculate stair stringers confidently and construct a robust and well-designed staircase in any building project. Remember always to consider safety guidelines and local building codes when designing and constructing stairs.