How to Build a Staircase in Your Home

When building a staircase, the most important thing is accuracy. Poorly made stairs can be dangerous, and building a staircase is a highly complicated undertaking. The steps for measuring to build a staircase in your home are listed below.

Step 1: Building Codes

Before you make a single measurement, check with your local authorities for specifications that will impact your staircase building. The building codes will give you a maximum riser height and a minimum tread size. You'll need to keep this code in mind when designing your staircase.

Most codes require that the maximum riser height is 7 3/8 inches and the minimum tread size is 10 inches. Handrails are usually required on both sides of wide staircases, as well as on a staircase rising 12 feet without a landing. Some areas may have stricter codes.

Step 2: Make a Blueprint

Before you begin, determine the amount of headroom you need and figure this into your calculations. Make a drawing of your staircase with the measurements written in, such as the total rise (the height from the floor to the next level where the staircase will end) and the height of each riser.

Step 3: Calculate How Many Treads

Divide the total rise (distance from floor to upper level) by 7.5 and then round up. This number is the total number of risers (stairs) you will need. This tells you how many treads you need. If the number you ended up with was 16, you'll need 15 treads (step surfaces). The 16th riser won't have a tread, because it leads up to the actual floor.

Knowing the number of treads gives you the entire length of the run of your staircase. Multiply the number of treads by their size (generally 10 inches). In the example above, 15 treads gives you a 150 inch staircase run. Finally, add the thickness of the top riser and the nosing of the bottom step for an accurate measurement.

Step 4: Calculate Length of Stairwell

Calculate the upper-floor construction—the thickness of the upper floor including the drywall, floor-joist and floor—to account for the right amount of headroom. Once you figure the thickness, add that to the amount of headroom you want, and then divide that number by the riser height (7 3/8 inches).

The final number tells you how many of the treads need to be in the clear opening in order to give you the proper headroom. Multiply it by 10 (the inches of the treads). Then add the measurements of the nosing and the top riser, and you'll have the appropriate stairwell length.

Step 5: Use the Measurements to Cut Your Pieces

Now that you have all the measurements you need, you can cut the stringers and risers according to your calculations and be assured that the staircase in your home will be accurate and sturdy. Most lumberyards sell wood that is especially good for use as treads. These boards lack the imperfections and tiny knots that could cause your staircase treads to split later.