A few lucky homeowners have a near-level surface for their deck. The rest of us need deck stairs to create safe access to our decks and yards.
Whether you’re redoing your current stairs or building new ones from scratch, learning how to build deck stairs can be a rewarding DIY task that boosts the safety of your deck and boosts your home’s curb appeal. Done right, they provide smooth, reliable access to your backyard, patio, or garden and become an integral part of your outdoor design.
Maybe you’re just curious about the process. Whatever you’re here for, I wanted to provide a step-by-step guide on how to build deck stairs. But there are some things you have to do first before jumping in.
Learn About Your City’s Code Requirements
Ensure you review local building codes before you start cutting stringers or selecting materials. There may be differences in the codes across Long Island, but generally, the language they include goes something like this:
- Stair rise should be at least 4 inches and no more than 7 ¾ inches
- The difference between the shortest and longest riser should not exceed ⅜ inch
- Stair treads must measure at least 36 inches wide
- Rail openings should not exceed 4 inches between balusters
You have to know these codes. There’s nothing worse than putting in the hard work only to get a penalty and have to restart the project. (And yeah, they do catch people from time to time).
You can find the codes you must follow on the city’s ecode360 site. I recently shared how this process looks for the Town of Huntington’s building code and deck zoning regulations. The steps I outline in that post also apply to other towns, so check it out.
Understanding the building regulations allows you to proceed with certainty, knowing your deck stairs will meet both durability and code requirements.
Get to Know All the Components of Deck Stairs
I feel like I always say this, but it applies here, too: deck stairs are not easy to build. There is a lot of work to do to make them follow code and to make them safe, comfortable, and nice-looking. Here is the anatomy of deck stairs:
Landing Pad
The landing pad is located at the staircase base and is a flat and stable platform constructed from materials such as concrete, pavers, or compacted gravel. Building regulations typically mandate a landing at the stairs’ base if the stairway’s total riser count surpasses a designated measurement. The landing pad offers a stable surface for foot traffic and holds the stringers securely at their base.
Stringers
Deck stairs depend on stringers for structural support. These wide boards are usually cut from 2x12s and run diagonally from the landing pad to the deck frame. The boards provide structural support to the treads and establish both the angle and spacing of the steps. You’ll come across two main types: Open stringers feature visible notches for treads and risers, while closed stringers use cleats or brackets to maintain a clean, solid profile when supporting steps.
Treads and Risers
The step surface consists of horizontal boards known as treads. Builders typically use two 2×6 boards or two 1×6 boards to construct the treads, although a single 2×12 board can serve just as well. Correct stringer spacing is essential to maintain structural integrity and prevent steps from sagging when walked upon.
The risers consist of vertical boards installed between individual treads. Most risers are created using fascia or decking material.
Stair Rise and Run
You need to understand the differences between stair “rise” and “run” (also called the tread) dimensions. Stair rise describes the vertical space between adjacent tread tops, and stair run defines the horizontal length of each step. The total rise measures the entire vertical distance from the ground or landing pad to the deck’s highest point. The total run measures how far the stairway extends across the horizontal space. Precise measurements of stair dimensions ensure safety and comfort when using the staircase.
Knowing these parts will help you whether you’re building the deck stairs yourself or discussing them with your contractor.
RELATED: 10 Tips Before Hiring a Deck Builder
Adding Stairs to Your Deck Design and Planning Access Points
Now that you know how to find the code requirements and the parts of deck stairs, it’s time to start thinking about location.
Where will the access points be? Why put them on the front as opposed to the side?
You should evaluate your stairs’ placement and functionality before measuring and cutting the stringers. Strategic placement of deck stairs improves foot traffic flow while expanding usable yard space and adding to your property’s curb appeal.
Envision how people will naturally transition between your house, deck area, and yard. Large decks may benefit from multiple staircases, which will help manage traffic flow. Installing a landing pad requires having a flat area at the stairs’ base. Choose locations without standing water or eroding soil.
Understanding your deck’s elevation will help you determine the staircase’s riser count and total length. We’ll talk through the tools and materials you’ll need in the next step, but so you know, it’s important to use a framing square or stair calculator to determine the rise and run dimensions for every step. Maintaining equal stair tread dimensions throughout the staircase helps comply with building regulations and provides a comfortable walking experience.
Finally, think about the look of the stairs. Select matching design elements for your deck and home, which include options like closed stringers and integrated lighting. A well-planned deck staircase design is an essential feature and adds a nice touch.
Gather Your Tools and Materials
Do a quick run-through of your current toolset. Make sure you have all of the following:
- Measuring tape – for accurate layout and spacing
- Framing square & speed square – crucial for marking rise/run on stringers
- Pencil & upside-down marking paint – for marking cuts and ground layout
- Circular saw & jig saw – for clean, precise cuts on stringers and boards
- Drill & hammer – for fastening screws and fitting hardware
- Bar clamps – to hold boards securely during assembly
- Level – ensures steps and railings are even and plumb
- Shovel & sledgehammer – for preparing the landing pad or leveling ground
- Utility knife & scissors – useful for cutting tape or packaging
- Paintbrush – for applying protective finishes
- Safety gear – always wear safety glasses during cutting and drilling
Got ’em all? Good. Now, here are all the materials you’ll need:
- Decking boards – for stair treads
- Fascia boards – to finish risers and stringer sides
- Railing system – for code-compliant safety
- Beam and joist tape – to protect framing from moisture
- Decking screws & fascia screws – corrosion-resistant fasteners for long-term durability
- Simpson Strong-Tie hardware:
- 3″ SDWS framing screws
- 5″ SDWS timber screws
- 8″ SDWS connector screws
- SD connector screws
- Stair stringer connector straps
Now, we get to the work.
Step-by-Step Guide to Building Deck Stairs
Step 1: Measure the Total Rise
The total rise refers to the vertical distance between your deck surface and the ground. Measure this first. Place a straight board on your deck’s edge and extend it outward until it reaches the landing pad. Position your level against the board and measure down to the ground surface. The total rise measurement represents your staircase’s full height distance and will help you determine the step count and height.
Step 2: Determine the Number of Risers
Next, you need to find out the total number of risers you need. Divide the total rise by a comfortable riser height, which varies between 6½ and 7¾ inches (again, check your town’s codes for the exact measurement). Adjust the calculation by rounding it to the closest whole number. This calculation provides an initial count of risers to determine their precise height in the next step.
Step 3: Determine the Number of Treads
Calculate the treads you need by subtracting one from the total risers. The top step won’t need a tread since it’s part of the surface.
Step 4: Measure the Staircase’s Total Run
The distance from the deck to the landing pad is calculated by multiplying the tread count with their individual depth. This typically measures around 10½ inches. Include the typical ¾ inch overhang in your calculations to achieve precise measurements.
Step 5: Calculate the Exact Riser Height
To find each riser’s exact height, divide the total rise by your number of risers. The measured riser height needs to stay within the building code limits, which typically range from 4 to 7¾ inches. Rework your riser count and redo the calculations if they’re not up to code.
Step 6: Lay Out and Cut the Stringers
Mark the stair pattern on a 2×12 board with your rise/run dimensions and a framing square. This board will act as your stringer. Utilize a circular saw for accurate cuts and complete inside corners by hand sawing to prevent cutting too far. To ensure proper stair assembly, you must cut the tread thickness from the bottom of the stringer.
Step 7: Test-Fit a Stringer
Ensure the first stringer fits correctly before cutting any other stringers. Ensure the stringer sits flush against the deck surface while reaching precisely ground level or landing. Use a spirit level to verify that every tread position remains level.
Step 8: Prepare the Landing Pad
Secure the stringer temporarily with clamps before marking the landing pad location. Usually, the minimum size for a landing pad is 36 square inches. Excavate the marked area and construct basic wooden forms. Pour in the concrete base. Done.
Step 9: Mark Fascia Board for Stringer Profile
Create a precise pattern of your stair stringer on the deck’s fascia board to achieve a clean and polished appearance. After cutting the fascia board to the correct shape, ensure it is ready to attach to your stair stringers.
Step 10: Attach Stringers to the Deck
Show each stringer’s location by marking the rim joist before securing them with a temporary guide block that is screwed in place. Attach the stringers to the deck with brackets and fasteners that meet building code standards. You should now mount the new posts to support your railing system.
Step 11: Reinforce with 2×6 Supports
To increase stiffness, fasten a horizontal 2×6 across the stringer backs. Secure the stringers by attaching two vertical 2×6 boards from the rim back to the horizontal brace.
Step 12: Confirm Square Alignment
The cross-measure technique requires you to measure diagonally from one corner of the stair frame to the opposite corner to verify that it is square. Adjust as needed until both measurements match.
Step 13: Install Risers and Treads
Install the risers by working from the bottom upwards. Secure every riser to the vertical surface between stringers before attaching the treads. Attach two deck boards to each tread while maintaining a ¼-inch space between them to allow for drainage and expansion.
Step 14: Pour the Concrete Landing
Fill your prepared landing pad form with concrete mixed to create a minimum 2,500 psi strength. After pouring concrete into the landing pad form, use a screed to level the surface, and then apply a magnesium float to achieve an even texture. Wait until the pad has fully cured before securing the stairs’ base.
