What You Need for This Project
Step by Step Instructions
Deck Stair Basics
After you’ve learned how to install wood decking and railings, you’re ready to add your deck stairs.
Deck stairs are typically made from 2-in. by 12-in. stringers spaced about 12 to 16 in. apart. They rest on a solid foundation and are attached to the deck with hangers. They have risers (also called toe kicks), treads, and railings. The stairs should be at least 36 in. wide.
You can follow our steps to build your own custom stringers or buy pre-cut stringers at your local Lowe's. Custom-built stringers allow you to match the dimensions of a set of stairs in your home, which will feel most comfortable. Whichever you choose, always make sure you follow building codes.
Determine the location of your bottom step. Set a level on top of the decking and measure the height at the point where you want your steps to end. Use this measurement to determine the number and height of the risers.
For example, if the height is 55 inches, divide this measurement by 7, the ideal height in inches for each step. Round to the nearest whole number to get the number of risers — in this case 8. Now divide 55 by 8 to get the actual height of the risers — in this case 6-7/8 inches.
- 55 ÷ 7 = 7.86 rounded up to 8 risers
- 55 ÷ 8 = 6.875 or 6-7/8 in.
If you use the deck itself as the top riser as with this deck, subtract one step.
In our guide, this deck will have treads made of 5/4-in. by 6-in. decking planks — two for each step — making the run for each step (the distance front-to-back) about 11 in. It also has 2-in. by 6-in. risers or toe kicks on the back for a clean look.
Combine the run of all your steps to get a total run length. Use this measurement to determine where to build your landing support.
Note: Some codes require toe kicks. You may want to check the height of steps or stairs that are already familiar to you — such as interior stairs of porch steps — to get a sense for a comfortable height. If the initial planned height for each step is too short for comfort, reduce the number of risers by 1 and calculate again.
Creating a Stair Landing
One method for a landing is to install concrete footers and posts, and secure the stringers to the posts.
Another common landing is a concrete pad. For this deck, the landing will be a pad on top of a 4-in. layer of gravel extending beyond the steps about 36 inches. Check your local code to be sure of specific requirements for your area.
Cutting the Stringers (Optional)
When you have determined the rise and run and installed the landing, you can mark the stairs on 2 x 12s to create stringers.
Set the Stair Gauges
Set stair gauges on a framing square at the height of the rise and the length of the run.
Mark the Top Run
Hold the square at the corner of a 2 x 12 board and mark the top run.
Mark the Rise & Run for All the Steps
Slide the square along the plank, and mark both rise and run for the next step. Continue marking until you have the correct number of steps laid out.
Mark Where the Stairs Attach to the Deck
At the run mark you made for the top step, subtract the thickness of the toe kick and strike a perpendicular cut line. This line indicates where the stairs attach to the deck. There won't be a toe kick at this point of the stairs.
Cut the Stringer
Cut the stringer with a circular saw and finish the cut for each step with a handsaw.
Cut the Rest of the Steps
Use this stringer as a template to mark and cut the others.
Attaching the Stringers, Toe Kicks & Treads
Cut a Board to Support the Stringers
Cut a board (for this deck a 2 x 8) the width of the steps to support the stringers below the rim or end joist.
Use pieces of the same 2 x lumber to attach the board against the bottom edge of the joist.
Brace the Support Board
Use additional 2 x lumber to brace the back of the support board against a joist or beam. Attach the braces with joist hangers or decking screws.
Mark the Hanger Location
Fit a hanger to a stringer and hold them against the support board, with the top of the stringer flush with the bottom of the joist. Mark the hanger location on the support board.
Secure the Hanger
Set the stringer aside. Secure the hanger to the deck with 10d nails and screws.
Attach the Stringers
Drill pilot holes and secure the hanger to the inside face of the stringer with nails and screws. Attach the remaining stringers the same way.
Cut Boards into Cleats
Cut 2 x 4 boards to fit between the stringers at the concrete pad. They'll function as cleats to secure the stairs to the pad. Place the cleats face down on the pad and attach them between the stringers.
Use a Hammer Drill
Use a masonry bit to drill through the cleats and into the pad.
Tip: A hammer drill will make drilling the concrete easier.
Attach Cleats to the Pad
Install concrete anchors to secure the cleats to the pad.
Put the Stairs in Place
Add washers and nuts and tighten the nuts to lock the stairs in place.
Attach the Posts to the Stringers
At the bottom of the steps, secure 4 x 4 posts to the stringers with bracing, anchors, and carriage bolts.
Cut the Toe Kicks & Treads
The treads should overhang the toe kicks by about an inch. Drill pilot holes at the ends and attach them to the stringers with screws.
Installing the Stair Railings
The stair railings consist of 2 x 4 top and bottom rails, 5/4 x 6 rail caps, and balusters.
Cut the Rails
Clamp the 2 x 4 rails along the steps and mark the angles where the rails meet the posts. Cut the rails at the marks.
Position the Top Rails
Use a baluster to determine the position of the top rails. Hold the baluster with the bottom end flush at the lower edge of the bottom rail. The top rail should be flush with the top end of the baluster.
Secure the Top Rails
Clamp the top rails to the posts at the correct height and secure them with screws.
Mark Where the Rails Meet the Posts
On the bottom posts, mark the angle where the top rails meet the posts.
Measure the Angle at the Rail & Posts
Use a T-bevel on the underside of the top rail to note the angle where the rail meets the posts.
Cut Rail Caps
Adjust your mitre saw to the indicated angle and cut rail caps to fit between the posts.
Screw in the Rail Caps
Position the rail caps with the inside edges flush to the inside faces of the top rails. Attach them with screws.
Attach the Balusters
Install the balusters just as you did with the deck railings. Drill pilot holes and secure to the top and bottom rails with screws. Use a 2 x 4 for spacing.
For stairs with 4 or more risers, most codes require a handrail on at least one side. Use a vertical 2 x 4 pressure-treated board with routed edges or an exterior-grade metal rail.
If you choose the 2 x 4 handrail, you can use a piece of 2 x material to create a 1-1/2-in. gap between the top rail and the handrail.
Get a Final Inspection
When the railings are finished, call your local building department for a final inspection.
Note: Always follow the manufacturer's recommendations for fasteners and structural hardware.
Working with Pressure-Treated Lumber
- Use fasteners and hardware labeled for treated lumber — stainless-steel or hot-dipped, galvanized screws.
- If the lumber is wet — it typically is when delivered from the store — butt it together tightly when building. Pressure-treated wood shrinks as it dries.
- Drill pilot holes in the ends of boards to prevent splitting when you nail or screw them together.
- Use wood rated for ground contact when necessary for the project.
- Wear a dust mask and eye protection when handling or cutting wood.
- Wash your hands after working with treated wood.
- Dispose of sawdust and waste according to local regulations.
- Don't burn pressure-treated wood.
- Don't use pressure-treated wood as mulch.
Read Health Canada's recommendations to stay safe around treated wood.
With the basic build for the deck complete, think about accessorizing your new outdoor space. See The Best Deck Designs, Layouts & Ideas for Your Backyard to get inspired.
How To Terms
- Set the Stair Gauges
- Mark the Top Run
- Mark the Rise & Run for All the Steps
- Mark Where the Stairs Attach to the Deck
- Mark a Line at the Bottom of the Steps
- Cut the Stringer
- Cut the Rest of the Steps
- Cut a Board to Support the Stringers
- Attach the Posts to the Stringers
- Cut the Toe Kicks & Treads
- Brace the Support Board
- Mark the Hanger Location
- Secure the Hanger
- Attach the Stringers
- Cut Boards into Cleats
- Use a Hammer Drill
- Attach the Cleats to the Pad
- Put the Stairs in Place
- Cut the Rails
- Attach the Balusters
- Build Handrails
- Get a Final Inspection
- Secure the Bottom Rails
- Position the Top Rails
- Secure the Top Rails
- Mark Where the Rails Meet the Posts
- Make a Cut on the Bottom Posts
- Measure the Angle at the Rail & Posts
- Cut Rail Caps
- Screw in the Rail Caps
Building a deck for the first time? Start your journey by exploring deck designs, ideas, and layouts that fit your needs.
These six videos will help you build that deck you've always wanted the right way. Learn how here.