By Kelin
Wed, Jun 4, 2025

How to Build Deck Steps and Stairs?

There are many things that can go wrong when building a deck staircase. These include issues with the deck and railings, as well as the size, height, and depth of the stair treads. To ensure that the steps are safe, local building codes must also be followed when building deck stairs. When replacing or building new deck stairs, we’ll help you through the process step-by-step.

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Table of Contents

What You Need to Build Deck Stairs

Building deck stairs requires many tools and materials. Keep in mind that you need to get all the right tools and buy good materials if you want your deck stairs to last. Below is a full list of items needed to build a deck staircase.

Circular saw
Drill
Framing square
Hammer
Jig saw
Paintbrush
Safety glasses
Paintbrush
Sledgehammer
Sledgehammer
Speed square
Decking boards
Fascia boards
Beam & joist tape
Fasteners
Stair stringer connector straps
Decking screws
Fascia screws

Developing a Deck Stair Plan

Cost Considerations

The first step is to work out the cost of building the deck stairs. Before you begin, budget and list all the costs of the tools and materials you will need. Deck stairs can cost from $1,500 to $2,000, but the price depends on the size and materials used. Simple materials such as deck boards, steps, fascia boards, stringers, screws, and hangers needed for an A15-story staircase will cost at least $1,500.

You should also consider the size of the staircase, the type of wood used, and the material of the handrail when calculating the price.

Know the Code

Before you begin your project, check the codes for deck stairs near you. Codes state that certain steps must be followed when making deck stairs to ensure the safety of yourself and others. If your project is not in compliance, you could be fined or even have to tear down the stairs.

The steps of a staircase must be at least 36 inches wide. While this is the minimum requirement, we believe the steps should be at least 48 inches wide so they don’t feel too narrow.

The height of the stairs should be no more than 7 ¾ inches and no less than 4 inches. There should be no more than ⅜ inch between the longest and smallest step heights on the stairs or the depth of the stairs. This is a very strict requirement, so plan your stringers very carefully.

The space between the railings should not exceed 4 inches. The distance between the bottom railing and the ground should not exceed 6 inches. To prove this, try putting a 6-inch sphere between the bottom rail and the tread. If the sphere fits through, the gap is too large.

Locating Stairs and Entrances and Exits

There are a couple of important things to consider when choosing a location for your deck stairs. First, think about how many people walk on the deck, where they usually go from, and where they come from. It’s important to place the stairs where they can be easily accessed without disrupting the flow of people. Also, make sure there are easy exits in case of an emergency.

Make a Plan Before You Start Building

Because deck stairs need to be accurate, it is important to have a plan in place before beginning construction. Make sure all the numbers are correct before you start building the deck stairs. This includes making sure that all stair rises (the height of the steps) and tread depths (the length of the steps) are the same.

If the steps are very different in length or height, it will be easy to trip. Remember, if you don’t plan well, you can run into trouble during the building process.

How to Build Stairs and Steps for a Deck

With all the necessary plans in place, it’s time to start building your new deck stairs. First, figure out how tall the deck is and how many steps and treads there are. Then, you can draw lines and cut out each piece before putting the stairs together. Here are some clear steps on how to build stairs for a deck.

Step 1: Measure the Total Height of the Entire Deck

First, find the total of all the steps to the top deck. Figure out where you want the stairs to end, keeping in mind that the slope should be around 40 degrees. This gives you the total height.

Next, place a straight board on the platform. Stretch this board out to the side so that it is above where you want the stairs to end, and then measure down the height straight to the ground. This gives you the total height, or total height of the deck stairs.

Step 2: Counting the Risers

Mark a board every 7 ¾ inches to find out how many risers are needed. This is the maximum height allowed by city regulations. The height of each step can be marked on the wood with a story pole. Place the riser pole next to the platform and count how many risers are between the platform and the floor. This will give you an idea of how many steps are needed.

Another way to do this is to divide the total number of heights obtained in Step 1 by 7 ¾. This will give you a rough idea of how many risers there are, but it is not an exact number. Round up to the nearest whole number. Most risers are 7 ¾ inches tall, but they can be as low as 4 inches or as high as 7 ¾ inches. You may need to figure out again how many risers of different heights are needed to fit.

Step 3: Calculate the Number of Pedals

This step is very simple. Subtract one step from the number of risers. You will need one tread for each step, except for the top tread, which consists of the deck surface.

Step 4: Calculate the Actual Distance to the Landing Pad

Once you know how many treads you need to have, you can figure out where the landing stage needs to be placed. Count how deep each tread is and multiply that number by the number of treads to get the exact distance.

Step 5: Determine the Exact Height of the Risers

First, find the total height of the riser boards. Then, divide this number by the number of riser plates you thought you already knew in Step 2. This is where you will find the correct height of each riser plate. It should be around 4 to 7 ¾ inches. If the rung plate height is higher than this range, you will need to add or subtract a rung plate and recalculate. Keep in mind that you will also need to adjust the landing pad distance and the number of treads when recalculating.

Step 6: Mark and Cut the Stair Beams

After you know the length and rise dimensions of the stairs, create a template on a scrapboard. To make the end of a 2×12 board 90 degrees, measure the board with a speed ruler. Then, mark the dimensions of the vertical beams on the sides and mark the dimensions of the horizontal beams at the top.

Draw a straight line between the two points to connect them. After cutting along the grain with a circular saw, you have a template of the run and rise dimensions, which can be used to mark the stairway crossbeams.

Remove the tread thickness from the bottom of the longitudinal beam. Once you have completed one transom, you can use it to guide the marking of the others.

After making sure that the second marking is correct, it is time to cut the notches. To prevent the longitudinal beams from becoming soft, cut them first with a circular saw near the corner of the mark. Then finish with a hand saw.

Step 7: Test Fitting the Longitudinal Beams

Check the fit of the crossbeam by leaning it against the deck. It should fit perfectly between the deck stairs and the platform and be flush with the deck. Use a spirit level to ensure that the treads are level even once the stairboards are in place.

Step 8: Selecting and Preparing the Landing

If the deck stairs and platform are to be made, the landings need to be prepared now. To find out the spacing between the longitudinal beams, start by clamping them to the deck. Then, start measuring the space for the concrete platform. The landing pad should measure at least 36 inches by 36 inches.

Dig the wood mold into the ground and secure it with stakes. Next, clamp the 4×4 to one end of the outer strut and paint a circle around it with marking paint. This shows the location of the bottom column. The longitudinal beams will then need to be removed and holes dug for the risers at the marked locations, which will be used to create the deck stairs with the platform.

Step 9: Painting the Stairs on the Fascia Boards

Cover the outside of the staircase with a cornice board. Draw the pattern of the staircase on it using the transom. Mark and cut the top and bottom of the cornice boards, then make sure they are installed correctly the second time. Then, attach the longitudinal beams to the inside of the fascia board using fascia screws spaced 9 inches apart.

Step 10: Attach the Longitudinal Beams to the Rim Joists

First, mark the longitudinal beam where the fascia board will be located in a straight line. Then, mark the position of the top of the fascia with a horizontal line. Attach a temporary 2×2 to the edge of the deck with the appropriate screws. This is where the crossbeam will be and the 2×2 can then be removed.

As a short-term fix, secure the cross member from the rear of the rim to the deck frame with three more deck screws. The center cross member is then secured in place with two deck screws. Place the new uprights into the holes previously dug and then secure the struts to the inside of the cross member with the screws.

Step 11: Connecting the 2×6 Supports

Stability is very important when building an outdoor staircase, so you will need to add support. Screw a 2×6 plank from the back across the width of all the struts. Then, take two more 2×6 planks and attach them vertically to the first 2×6 plank and to the back of the deck edge.

Step 12: Make Sure Everything Is Flat and Straight

First, nail two nails to each stringer and then nail the bottom riser boards to it. Now, you need to make sure everything is solid and square. Next, cross-measure the basic structure that has been erected, measuring the top and the bottom. Both cross-sections must be the same size. If they don’t match, gently tap the structure to move it a little to the side and then take a few more measurements until they both match.

Step 13: Installing the Treads and Risers on the Staircase

Now it’s time to put the rest of the treads and risers in place. The steps should be screwed on before screwing the treads to the top. Leave a 1/4-inch gap between the boards. Repeat this until the top of the stairs.

Step 14: Pouring Concrete and Securing the Stairs to the Deck

Pour at least 2,500 psi of concrete to create the platform, then level it with a 2×4 straight board. After that, you can use a magnesium trowel to finish the concrete. A magnesium trowel is a flat piece of magnesium (or aluminum) with a handle on one end. It allows you to float the concrete at the angle and pressure you want.

Once this is done, you are ready to use your do-it-yourself deck stairs.

Final Thoughts

The most important thing to remember when building deck stairs is to stick to your budget, measure everything carefully, and make sure everything is securely attached. If you follow these steps and the rules for making them, you won’t go too far wrong.

If you’re ready to get started and are confident that you can complete the project on your own, then find a retailer to start preparing your tools and materials. Of course, you also hire professional contractors.