The final part of the deck build is the stairs. Building stairs takes some math and a little know-how. Follow our step-by-step guide for a safe set of wood deck stairs.

Steps
30
Difficulty
Expert
Time Required
1Weekend
Estimated Cost
$$$

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.

Stair Measurements

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.

STEP ONE

Set the Stair Gauges

Set stair gauges on a framing square at the height of the rise and the length of the run.

STEP TWO

Mark the Top Run

Hold the square at the corner of a 2 x 12 board and mark the top run.

STEP THREE

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.

STEP FOUR

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.

STEP FIVE

Mark a Line at the Bottom of the Steps

At the bottom step, subtract the thickness of a tread from the rise and mark a line perpendicular to the rise. This is a cut line to allow you to shift the entire set of stairs down. When the treads are installed, this cut will make the bottom step the same height as the others.

STEP SIX

Cut the Stringer

Cut the stringer with a circular saw and finish the cut for each step with a handsaw.

STEP SEVEN

Cut the Rest of the Steps

Use this stringer as a template to mark and cut the others.

Attaching the Stringers, Toe Kicks & Treads

STEP ONE

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.

STEP TWO

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.

STEP THREE

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.

STEP FOUR

Secure the Hanger

Set the stringer aside. Secure the hanger to the deck with 10d nails and screws.

STEP FIVE

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.

STEP SIX

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.

STEP SEVEN

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.

STEP EIGHT

Attach Cleats to the Pad

Install concrete anchors to secure the cleats to the pad.

STEP NINE

Put the Stairs in Place

Add washers and nuts and tighten the nuts to lock the stairs in place.

STEP TEN

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.

STEP ELEVEN

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.

STEP ONE

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.

STEP TWO

Secure the Bottom Rails

Attach the two bottom rails between the top and bottom posts with screws.

STEP THREE

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.

STEP FOUR

Secure the Top Rails

Clamp the top rails to the posts at the correct height and secure them with screws.

STEP FIVE

Mark Where the Rails Meet the Posts

On the bottom posts, mark the angle where the top rails meet the posts.

STEP SIX

Make a Cut on the Bottom Posts

Cut the angle on the bottom posts.

STEP SEVEN

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.

STEP EIGHT

Cut Rail Caps

Adjust your mitre saw to the indicated angle and cut rail caps to fit between the posts.

STEP NINE

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.

STEP TEN

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.

STEP ELEVEN

Build Handrails

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.

STEP TWELVE

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

Guidelines

  • 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.

 

Safety

  • 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.

Finishing Touches

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

Tools, products, materials, techniques, building codes, and local regulations change; therefore, Lowe's assumes no liability for omissions, errors, or the outcome of any project. The reader must always exercise reasonable caution, follow current codes and regulations that may apply, and is urged to consult with a licensed professional if in doubt about any procedures.

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