Raise your DIY skills to the next level
Learning how to build stairs is challenging, even for experienced DIYers. However, whether your remodel requires you to build indoor stairs or out, there are a few simple tricks to know that can make the job easier.
With careful planning and measuring, you can build a staircase that’s both functional and stylish.
There are several things to consider before starting your stair-building project. Preparation starts by getting familiar with a few stair-related terms.
Tread is the part of the stair where you place your foot.
Rise is the total vertical distance from the top to the bottom of the staircase.
The nosing is the part of the tread that overhangs the riser.
Run is the total horizontal distance that the staircase occupies.
The risers are the vertical boards between treads that close the stairs.
Skirt boards line the outside of the staircase for appearance and safety.
The header is the mounting surface at the top of the stairs.
The landing is the mounting surface at the bottom of the stairs.
Stringers are the support structure of the staircase under the treads.
Hangers attach the stringers to the header.
Knowing the terminology will make obtaining a permit at your local permitting office a little easier. Every staircase needs a building permit and at least one inspection when the staircase is complete to ensure it meets the strict building codes that govern staircase measurements.
Staircases are subject to building codes to keep them safe. However, before and during their construction, pay attention to where you step to avoid falling from one floor to a lower one. Also, as you’re building, secure the stair treads before using them as a ladder for working higher on the structure.
You can build an indoor staircase anytime you like. Installing deck stairs outside is a different story. You’ll likely need to wait until the ground is no longer frozen if your steps require independent footings. Also, building exterior stairs is safer and more enjoyable during dry weather.
Before you can learn how to build stairs, you’ll need to establish the overall height of the staircase.
For an indoor staircase, you’re likely working with a level floor. Simply measure the distance from the upper finished floor height to the landing or floor below to determine the total rise of the staircase.
For an outdoor staircase where the ground is uneven, determine the distance that the stairs will reach out or, in other words, its total run.
Find the distance by leaning a straight board from the top of the stair header to the ground at a 32-degree angle.
Determine the angle using an angle gauge tool. Mark the end location on the ground.
Have an assistant extend a long, straight board out from the top of the stair header to the mark on the ground. Level the board with a bubble level.
Measure the vertical distance from the bottom of the board to the ground. That number will be the total rise of the outdoor staircase.
Standard building codes govern stair measurements. The minimum and maximum rise of individual stairs must be between 4 and 7-3/4 inches.
A typical stair riser is around 7-1/4 inches tall. First, divide the total rise by 7 inches to achieve a height near that number.
For example, if your total rise is 9 feet, divide 108 inches by 7 to reach 15.43 inches. Round down to 15, which will be the total number of risers in your staircase.
If your top stair isn’t going to be level with the floor above, subtract one riser for a total of 14 risers with a total rise of 101 inches.
To determine the number of treads, subtract one from the number of risers. Our example will equal 13 treads.
Now for the more precise calculations for building a staircase.
To find the precise height of each riser, divide the total rise of the stairs by the number of risers.
In our example, divide 101 by 14 to equal 7.21 inches per riser.
Save that number for later.
The next crucial measurement for building steps is the length of the stringers.
First, determine the depth of each stair tread. A good rule of thumb is to keep the sum of the run and rise of each stair near 18 inches.
For our example, let’s choose 11 inches deep. The sum of 11 and 7.21 is 18.21 inches which is, as they say, close enough.
Now multiply the depth of each stair tread (11) by the number of treads (13) to determine the total run of the staircase (143 inches).
To find the length of the stringers, multiply the total rise of the staircase, excluding the distance from the top tread to the upper finished floor height by itself (101 x 101 = 10,201).
Multiply the total run of the staircase by itself (143 x 143 = 20,449).
Add the two totals together and find the square root of the total to determine the total length of the stringers and skirt boards (175.07, or 14.6 feet). Now you know that you’ll need stringer lumber that’s at least that long.
Use a 2-by-12 board longer than the total length of your stringers to make the first one.
Affix the stair gauges to a carpenter’s square. Place one at the riser height and one at the stringer height on the other side of the square.
In our example, mark 7.2, or just shy of 7 1/4 inches, and 11 inches on the other side.
Starting at the bottom of the stringer, clamp the carpenter’s square so that the corner is on the face of the board and the gauge’s stops are snug against its edge.
Trace the triangular shape onto the board. Be aware of which side of the square represents the riser and which is the tread.
Repeat the process until you have drawn your staircase's total number of stairs.
With the carpenter’s square or another straightedge, make a line horizontal to the bottom of the stringer that represents the thickness of your tread lumber. You’ll cut off this excess later.
Make a cut line representing the excess material at the top of the stringer and square the board to the header lumber.
Use a circular saw to perform the rough cuts and finish with a more precise saw.
Cut the top and bottom excess material from your stringer with a circular saw.
Make cuts with a circular saw along your cut lines for each step.
Stop cutting approximately 1/4 inch from the inside corner where the lines meet.
Remove the triangular waste from the string by finishing each stair cut with a jigsaw or handsaw.
Now is an excellent time to make sure everything is looking good.
Set the cut stringer in place.
Check the treads for level with a torpedo level.
When satisfied that the first stringer is correct, it becomes a template for the following pieces.
Lay the cut stringer on another 2x12.
Line the cut stringer’s long edge up with the other board’s edge and clamp it in place.
Trace the outline of the cut stringer onto the uncut board.
Repeat for all stringers in your staircase.
Skirt boards affix to the outer edges of the staircase as decorative trim, for safety, or both.
Lay the cut stringer on another 2x12 and clamp it with the long edges aligned.
Trace the bottom and top cuts onto the board. Exclude tracing the individual steps.
Cut the skirt board on the marks with a circular saw.
Cut the remaining stringers following the traced lines from step eight. Remember to stop short of the inside corners and finish the cuts with a jigsaw or handsaw to avoid overcutting and weakening the stringers.
Depending on your staircase, you can perform this step now or after you install the stringers.
Align a cut skirt board to a cut stringer and clamp them together. Be sure to position the skirt board on the outside of the stringer.
Affix the skirt board to the stringer using 2-inch screws.
Repeat for the other side.
For the most secure installation, use steel stair hangers to attach the staircase to the house structure.
Add the height of one riser plus the thickness of one tread and make a mark on the header representing that total.
Fasten the top of the stringers to the header board using staircase hangers and joist nails at your mark on the header.
After attaching the two outer stringers, square the staircase by matching the measurements between the opposite corners at the top and bottom of the stairs.
Attach the bottom of the stringers with L-angle joist hanger brackets on the inside of the stringers.
Your staircase may still feel a little flimsy. Installing the risers will fix that.
Measure the width of the staircase between the skirt boards.
Cut 1x8 lumber to that measurement until you have enough risers.
Use a table saw to rip the risers to the correct height if necessary.
Start at the bottom and install each riser with 2-inch screws. Use at least two screws per stringer.
Stair treads less than 11 inches deep will require at least a 3/4-inch nosing on each one.
Using the riser width measurement, mark and cut the treads to the correct width.
Use a table saw to rip the treads to the correct depth if necessary.
Start at the bottom of the staircase and install each tread by driving 3-inch screws through the tread and into each stringer.
Before calling the city to schedule your inspection, install a railing or handrail that meets building code requirements. That could be a whole project in itself. Call a local handrail installer if you'd like help with that part of your project.
Building a staircase is an excellent project to enhance your DIY skills. You can create a basic indoor staircase for under $500, plus the cost of a permit in less than a day.
However, it’s likely too large of a project for a beginning DIYer or those who simply don’t have a full day to devote to the project.
In that case, a carpenter near you or a local stair installation company can perform the task for you. The average cost of professional staircase installation ranges from $900 to $4,000.
The International Building Code requires individual step risers in a residential staircase to measure between 4 and 7-3/4 inches and the maximum rise of a staircase not to exceed 12 feet between landings. Individual step treads can’t be less than 10 inches deep.
Standard residential stair treads need to be at least 1 inch thick. Open staircases without risers must be at least 1-1/2 inches thick.
The maximum measurement between stair stringers is typically 18 inches on-center. However, the International Building Code only requires that a staircase can resist a live load of 40 pounds per square foot in residential construction.
