How do you cut deck stair stringers?

November 13, 2024

Properly cutting deck stair stringers is crucial for creating safe, sturdy stairs. This step-by-step guide will walk you through the process.

Building a deck requires precision, especially when it comes to constructing stairs that are both functional and safe. Stair stringers are the backbone of any deck staircase, supporting the treads and risers, and ensuring the stability of the entire structure. This guide will provide you with a clear roadmap for cutting your stair stringers correctly.

Steps Overview:

Measure and Mark: Begin by determining the necessary dimensions of your stairs—rise, run, and width. Use these measurements to mark your stringer board accurately.
Cut the Treads and Risers: With your measurements marked, use a circular or miter saw to cut the treads and then the risers to the specified sizes.
Shape the Stringers: Outline the stringer profile on the board, and then cut along these lines with a jigsaw or circular saw.
Installation: Place the stringers at the appropriate location on your deck and secure them firmly to ensure they provide a solid foundation.
Final Assembly: Attach the treads and risers to the stringers and check that everything is level and sturdy.

By following these detailed steps, you can confidently craft a set of stairs that enhances your deck's accessibility and aesthetic appeal.

Measure and Mark the Stair Stringers

Accurate measurement and marking are the first crucial steps in cutting deck stair stringers. Here's how to ensure your stair dimensions are perfect for your deck:

Determine Stair Dimensions:

Rise: This is the vertical height between the surfaces of two consecutive steps. For most decks, a rise of 6-8 inches is typical.
Run: The horizontal depth of one step, usually about 10-12 inches.
Width: Decide on the overall width of the stairs, which affects the length of the treads and the number of stringers required.

Measure and Mark the Stringer Board:

Start by marking the total rise on one end of your stringer board. Use a framing square to extend this line across the width of the board, ensuring it’s perfectly horizontal.
Next, measure and mark the total run along the bottom of the board, making sure the line is parallel to the top edge of the board.
Connect these marks to outline the stair’s slope, which will guide your cuts for each step.

These preliminary steps form the blueprint for your stair stringers, setting the foundation for precise cuts that will lead to a stable and safe staircase.

Cut the Stair Treads

Once you have your stair stringers measured and marked, the next step is cutting the stair treads. Here’s how to ensure each tread is precisely cut for a perfect fit:

Select the Appropriate Saw:

Circular Saw: Ideal for making straight cuts across the tread material. It’s versatile and portable, making it a popular choice for outdoor projects.
Miter Saw: Best for achieving clean, precise cuts, especially if your design calls for angled treads.

Cut the Stair Treads:

Lay your tread material on a stable work surface. Use clamps to hold it securely in place to prevent any movement during cutting.
Align the saw blade with the marks you made for the tread dimensions. Ensure the blade is set to the correct depth—just deep enough to cut through the material.
Cut slowly and steadily, following the marked lines to ensure accuracy. Repeat for each tread.

Using the right tools and techniques will help you achieve smooth, straight cuts, ensuring your stair treads fit perfectly and contribute to the overall safety and beauty of your deck stairs.

Cut the Stair Risers

After cutting your stair treads, the next step is to prepare the stair risers, which are crucial for the vertical support of each step. Here’s how to accurately measure, mark, and cut the riser boards:

Measure and Mark the Riser Heights:

Calculate the riser height by measuring the vertical distance from the top of one tread to the top of the next. Ensure each riser height is consistent to maintain uniformity throughout the staircase.
On each riser board, use a straight edge and a pencil to mark the calculated height clearly. Ensure that the lines are perpendicular to the edge of the board to guarantee straight, vertical risers.

Cut the Riser Boards to Size:

Choose a saw that will provide a clean, straight cut. A circular saw or a miter saw is most commonly used for cutting risers.
Secure the riser board to your work surface with clamps to prevent any movement during cutting.
Align the saw blade with your marked lines. Check the saw’s depth setting to ensure it only cuts through the thickness of the board.
Cut each marked line steadily, following the vertical marks precisely to ensure that your risers fit snugly against each tread.

By carefully measuring and cutting each riser, you’ll help create a stable and visually appealing staircase, enhancing the overall safety and durability of your deck stairs.

Cut the Stair Stringers

Cutting the stair stringers accurately is crucial for the structural integrity of your deck stairs. Here’s how to precisely measure, mark, and cut the stringer profile:

Measure and Mark the Stringer Profile:

Lay the stringer board flat on a stable surface. Using the measurements you obtained for the rise and run, place a framing square on the stringer to mark out each step's profile. Align the square's tongue (vertical part) and blade (horizontal part) to the rise and run measurements respectively, drawing the profile of each step along the board.
Repeat this step until you have marked the complete series of steps (treads and risers) along the length of the stringer.

Use a Jigsaw or Circular Saw to Cut the Stringer Profile:

For the initial rough cuts, use a circular saw. Cut along the marked lines, stopping just short of the corners to avoid overcutting. This helps preserve the strength of the stringer.
To finish the cuts cleanly, especially the corners that the circular saw can't fully reach without overcutting, switch to a jigsaw. This tool allows for more precise cuts and can handle the intricate angles at the corners of the steps.

By carefully following these measurement and cutting techniques, you will ensure that your stringers fit perfectly and support the weight of the stairs, providing a safe and long-lasting staircase.

Install the Stair Stringers

Proper installation of stair stringers is essential to ensure the stability and safety of your deck stairs. Here’s how to position and secure the stringers effectively:

Position the Stringers in the Desired Location:

Determine the placement of the stringers along the deck where the stairs will descend. They should be spaced evenly, typically about 16 to 24 inches apart, to provide adequate support for the stair treads.
Check the alignment of each stringer at the deck’s edge. Ensure that they are straight and that the top of each stringer is flush with the deck surface. Use a level to verify that they are vertically straight.

Secure the Stringers to the Deck Frame:

Start by attaching a stair hanger or similar bracket at the top of each stringer to the deck frame. This bracket should be designed to hold the stringers securely and bear the load of frequent use.
Use galvanized screws or heavy-duty fasteners to secure the brackets. Screwing directly into the deck frame will provide strong, lasting support.
For added stability, you may also attach the bottom of the stringers to a concrete pad or a footing below the frost line if the stairs reach the ground.

By following these steps, your stair stringers will be securely attached to the deck, providing a firm foundation for your deck stairs and ensuring the safety of all who use them.

Finalize the Stair Assembly

Completing the stair assembly involves attaching the treads and risers to the stringers and ensuring the structure is secure and level. Here’s how to finalize your deck stair assembly:

Attach the Stair Treads to the Stringers:

Place each stair tread on the horizontal cuts of the stringers, ensuring they are centered and extend evenly across the width of the stairs.
Secure each tread with decking screws, drilling them through the tread and into the stringer. Use at least two screws per end of each tread to ensure a strong, squeak-free bond.

Install the Stair Risers:

Position each riser against the vertical face of the stringers between each tread. Risers should fit snugly to minimize gaps and provide a clean look.
Attach the risers to the stringers using finishing nails or screws. Ensure the fasteners are appropriately sized to penetrate both the riser and the stringer securely without protruding.

Ensure the Stairs are Level and Sturdy:

Use a level to check each tread and riser to ensure they are horizontally and vertically straight.
Apply weight to various parts of the stairs to test for any movement or instability. Tighten any fasteners where necessary and add support brackets if required for additional strength.

By meticulously attaching the treads and risers and ensuring everything is level and secure, your deck stairs will be safe, durable, and ready for use.