Total Run - Staircase Building Step Measurement
The total run is the horizontal distance between the first stair tread and the last one. The picture below provides you with an excellent illustration of the total run, for a staircase. This is another critical measurement used by stair builders, to figure out and build a stairway.
There's two ways to use your total run or to even
figure it out. Let's start with the first one.
The most common way used by architects, to figure out the total run for a staircase is to use each individual tread as a starting measurement. For example, you have 11 - 7 1/2 inch risers, so we now know that you're going to have 10 treads. You're always going to have one less tread than risers.
A comfortable stair tread for a 7 - 1/2 inch riser would be 10 inches. This is when the architect multiplies these two numbers together and comes up with a total run. 10 individual treads multiplied by 10 inches will provide us with a 100 inch total stairway run. This is the most common method used by stair designers for figuring out the total distance between the first and the last tread.
The second method is even easier, someone will give you a distance or you will have a fixed distance to work with. Then you will divide the amount of treads into that distance.
For example, you have 90 inches that you're going to be working with as your total run. This is the horizontal distance between the top floor stair head out and the hallway below. You can't extend your stairway into the hallway, without creating building code issues.
You know that you need 10 steps so you divide 10 into 90 and come up with 10 - 9 inch treads. If this measurement is acceptable to your local building department and meets your local building codes, you can build your stairway. If it doesn't, then you're going to need to make some modifications to the building.
I told you that I had two methods, but I didn't tell you that they were both going to be easy. Coming up with the total run for a stairway is difficult, sometimes in small buildings.
Stairs / Stair Glossary
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