# How To Build Stairs - Part 1a

Free Downloadable Staircase Calculator (requires Excel) - works in conjunction with this information.

Letters in Orange signify that the formula is on the free automatic staircase calculator.

The simplest set of stairs to make is a straight staircase as shown in Figure 1.

Figure 1 - Straight Stairs

The biggest obstacle to building a straight run set of stairs is space.

Besides requiring the "Total Run" of the stairs you need additional space at the bottom of the stairs in order to create a landing, which, at a minimum is the width of the stairs.

Stairs have some dimensional flexibility. However, there are guidelines and building codes which have set some minimum and maximum staircase design rules and numbers.

The one dimension that has no flexibility is the "Total Rise" as shown in Figure 2. This is the height of the staircase from the top of the finished basement floor to the top of the finished floor at the top of the stairs.

Figure 2 - Straight stairs showing total rise and total run

Table 1 - Fraction To Decimal Conversions | |||||||

Fraction | Decimal | Fraction | Decimal | Fraction | Decimal | Fraction | Decimal |

1/32 |
0.0313 |
9/32 |
0.2813 |
17/32 |
0.5313 |
25/32 |
0.7813 |

1/16 |
0.0625 |
5/16 |
0.3125 |
9/16 |
0.5625 |
13/16 |
0.8125 |

3/32 |
0.0938 |
11/32 |
0.3438 |
19/32 |
0.5938 |
27/32 |
0.8438 |

1/8 |
0.125 |
3/8 |
0.375 |
5/8 |
0.625 |
7/8 |
0.875 |

5/32 |
0.1563 |
13/32 |
0.4063 |
21/32 |
0.6563 |
29/32 |
0.9063 |

3/16 |
0.1875 |
7/16 |
0.4375 |
11/16 |
0.6875 |
15/16 |
0.9375 |

7/32 |
0.2188 |
15/32 |
0.4688 |
23/32 |
0.7188 |
31/32 |
0.9688 |

1/4 |
0.25 |
1/2 |
0.5 |
3/4 |
0.75 |
1 |
1 |

**Note:** You will have to round decimal places to the closest 1/32 of an inch on conversion from decimal to fraction, see Table 3.

To determine the width of each step and the height of each riser you start with the "Total Rise" measurement. From this dimension you can determine how many risers and the height of each riser or stair. Most building codes have set a maximum stair rise of 7 3/4". For the purpose of this example we will use a "Total Rise" of 106 3/4".

The calculation to determine how many risers you require is:

A Total Rise ÷ Max. Stair Rise = Number Of Risers

106 3/4 ÷ 7 3/4 = 13.77

As it is impossible to have a fraction of a number of risers, the number obtained is rounded off to the next highest whole number, in this case 14.

Straight Staircase | "L" Staircase" | Winder Staircase | |||||

Part 1b | Part 2a | Part 2b | Part 3 | Part 4 | Part 5 | Part 6a | Part 6b |

Staircase Terminology | Repairing Stairs | Stair Tread Repair Or Replacement |