Indoors » Stairs » Cutting Stair Stringers

Cutting Stair Stringers: A Comprehensive DIY Guide for Perfect Stairs

In any sturdy, well-built home, stair stringers are more than just an underpinning feature, they are a critical component that demands attention and respect. This guide is tailored to cater to both novices and seasoned builders. Our focus is on practicality and safety, ensuring that by the end, whether you’re decking out your home with a new staircase or refurbishing an old one, you’ll be equipped with the knowledge to do it right.

Understanding the fundamentals of stair construction isn’t just about getting from one floor to another, it’s about crafting an integral part of your home that’s both functional and safe. With an eye on detail and simplicity, we will walk through the process, ensuring that everyone, regardless of their skill level, can follow along and apply these practices to their projects.

Understanding Stair Stringers

At its core, a stair stringer is the structural heart of a staircase. It’s not just a board with a series of notches – each cut and measurement plays a pivotal role in the stability and safety of your stairs. The stringer outlines the rise (height of each step) and run (depth of each step), forming the essential framework upon which the stairs are built.

Now, stair stringers aren’t a one-size-fits-all solution. There are nuances to consider, such as the material choice – indoor stairs might favor aesthetics with woods like oak or pine, while outdoor stairs, like those on a deck, require durability, often calling for pressure-treated lumber to withstand the elements.

The takeaway here is straightforward: the stringer is fundamental to the integrity of your staircase. It’s the linchpin that ensures every ascent and descent is secure.

Tools and Materials Needed

To embark on this stair-building journey, you need the right arsenal of tools and materials at your disposal:


  • Circular Saw: This will be your primary tool for making the major cuts on the stringers.
  • Framing Square: Essential for accurate measurements and angles. A carpenter’s best friend.
  • Stair Gauges: These simple attachments to your square ensure consistency in your markings.
  • Chalk Line: Ideal for marking long, straight lines across your stringer material.
  • Tape Measure: Accuracy is key in stair building, a reliable tape measure is indispensable.
  • Saw Horses: Providing a stable base for your work.
  • Hand Saw or Jigsaw: Handy for the finishing touches and intricate cuts.


  • Stringer Material: Choice varies based on application – pressure-treated lumber for outdoor, hardwoods for indoor.
  • Fasteners: Quality matters – opt for galvanized or coated screws/nails to prevent rust.
  • Adhesives: A sturdy construction adhesive can add an extra layer of stability.

Armed with these tools and materials, you’re set to take on the task of building a staircase. Remember, quality tools lead to quality work. As we progress, each step will be a building block towards a staircase that is not just a functional necessity, but a testament to craftsmanship and safety.

Planning and Designing Your Staircase

In approaching the design of your staircase, the initial step is to calculate the rise and run, a fundamental yet critical aspect of stair building. This isn’t mere arithmetic but the backbone of functional and safe stair design. The total rise – the vertical distance from one floor to the next – divided by a comfortable riser height (usually about 7 inches) will dictate your number of steps. This calculation is more than just numbers, it’s about ensuring a comfortable and natural step for the user.

Local building codes are your blueprint for safety and legality. These regulations, varying by region, set the standards for riser heights, tread depth, and other critical dimensions. Adhering to these isn’t just about compliance but also about the safety and comfort of those who will use your stairs.

When considering stringers for outdoor deck stairs, material choice is paramount. Pressure-treated lumber is not a mere recommendation but a necessity, offering longevity against the elements. For indoor stairs, aesthetics come into play, and hardwoods can elevate the visual appeal. In both cases, the material choice is a balance between functionality and style, durability and design.

The Process of Cutting Stair Stringers

Marking and cutting stair stringers are tasks that demand precision and patience. Equipped with a framing square and stair gauges, you embark on a process that turns raw lumber into the skeletal framework of your staircase. This task is about meticulous measurement and careful execution.

  1. Marking the Stringer: Clamping your stair gauges to the framing square at the rise and run measurements allows for consistent, accurate marking. It’s a method that transforms a complex layout into a manageable task.
  2. Cutting the Stringer: With a circular saw, the stringer begins to take shape. The trick here is to saw only up to the intersection of step lines, preserving the integrity of the wood. A handsaw might be necessary for finishing cuts, a small but significant step ensuring strength in your stringers.
  3. Adjusting for Challenges: Not every project is straightforward. Uneven ground or unique architectural features may require custom adjustments to stringers. This stage is about adaptability and problem-solving, ensuring your stringers fit perfectly in their intended environment.

Installation Tips and Tricks

Installation is the final, crucial stage where your stringers find their place. For deck stairs, securing the stringers involves ledger board brackets or heavy-duty angles, ensuring a stable connection to the framing. Ensuring the stringers are plumb and evenly spaced is not just about aesthetics but foundational to the staircase’s safety and functionality.

Weight distribution across stringers is akin to a well-balanced equation. Each stringer should bear an equal load, a consideration that ensures longevity and safety. Adding risers and extra supports isn’t an afterthought but a reinforcement of this balance, adding rigidity and stability to the structure.

In crafting stairs, whether for a deck or indoors, the fusion of precision, adherence to codes, and practical application results in not just a functional staircase but a testament to thoughtful craftsmanship. This process, grounded in detail and real-world application, is the essence of building stairs that are safe, durable, and aesthetically pleasing.

Common Mistakes and How to Avoid Them

In my many years on job sites, one truth has always stood out: a small misstep in the early stages can lead to major setbacks later, especially when it comes to stair stringers. Let’s delve into these pitfalls and how to navigate them.

  1. Incorrect Measurements: Precision is key. An erroneous measurement can render a staircase uncomfortable at best, and hazardous at worst. Always double-check your measurements. A discrepancy of even a quarter-inch can significantly alter the comfort and safety of the stairs.
  2. Overcutting the Stringers: Precision cutting is as much an art as a science. Overcutting the intersection of tread and riser lines weakens the stringer’s structural integrity. Maintaining the integrity of these intersections is crucial for long-term durability.
  3. Ignoring the Landing Surface: The way your stringer meets the landing or deck is a cornerstone of stair stability. Ensuring a flush and secure fit is paramount. It’s not just about the right angle, but also about the right support.
  4. Forgetting About Wood Treatment: For outdoor stairs, neglecting to use pressure-treated wood is akin to leaving your project vulnerable to the elements. This oversight can lead to premature wear and potentially dangerous weakening over time.
  5. Skimping on Support: A common oversight is underestimating the support needed for stringers. This can lead to a shaky and unsafe staircase. Adequate bracing and secure attachment points are non-negotiable for safety and longevity.

FAQ Section

How do I calculate the number of steps I need for my stringers?

The calculation is straightforward: divide the total vertical height by the height of each riser. For example, if the height is 30 inches and you plan for 7-inch risers, you would need about 4 steps. Always round down to ensure safety.

Can I use the same techniques for both indoor and outdoor stair stringers?

While the fundamental techniques remain consistent, outdoor stairs demand materials that can withstand the elements. Outdoor stairs benefit from pressure-treated wood to combat rot and insect damage.

What’s the best wood to use for deck stair stringers?

Pressure-treated lumber stands as the most practical choice for its resistance to rot and insects. For a more aesthetic appeal, cedar or redwood can be used, though they come with a higher price tag.

How can I ensure my stair stringers are safe and meet building codes?

Familiarizing yourself with local building codes is essential. These codes provide guidelines on riser heights, tread depth, and overall construction to ensure safety and structural integrity.

Can I repair a damaged stringer or do I need to replace it entirely?

The decision to repair or replace depends on the extent of the damage. Minor cracks can often be repaired, but significant structural damage typically necessitates replacement.

What are the best practices for attaching stringers to a deck?

Secure attachment is vital. Use heavy-duty brackets and bolts for attachment, and ensure that the stringers are perfectly plumb. For added stability, additional support may be necessary.