1 / 19

# Presentation 36:

Presentation 36:. STAIR RISE AND RUN. Unit Run. Unit Rise. Unit Run. Total Rise. Unit Rise. Unit Run. Total Run. Unit Rise. Rise and Run. Stairs have a rise and run. Similar to rafters, rise is vertical and run is horizontal. Rise and Run. Download Presentation ## Presentation 36:

E N D

### Presentation Transcript

1. Presentation 36: STAIR RISE AND RUN

2. Unit Run Unit Rise Unit Run Total Rise Unit Rise Unit Run Total Run Unit Rise Rise and Run • Stairs have a rise and run. • Similar to rafters, rise is vertical and run is horizontal.

3. Rise and Run • Unit rise and unit run do not include the tread nosing. Nosing Tread Unit Run Riser Unit Rise

4. Stair Design • Building stairs involves several options. Second Floor • In this design there are threetreads and four risers. First Floor

5. Stair Design • Another set might have four treads and five risers. • Deciding which to use depends on stair usage. Which is best?

6. Rise/Run Rule • A formula is used to keep the stairs at a safe and comfortable angle. • Rise + Run = between 17″and 18″ • Run + two Rises = between 24 and 25 may also be used. • The first one will be used for this demonstration. • 7 ½″ rise and 10″ run are numbers that fit the formula. • 7 ½″ + 10″ = 17 ½″

7. TotalRise Starting Information • Total rise must be measured. Second Floor • Assume for now there is ample room to land the stairs on the first floor. First Floor

8. Number of Risers • Unit Rise = Total rise ÷ # of Risers • # of Risers = Total Rise ÷ 8 (Rounded up) (8 is used as a starting point) e.g., If the total rise is 30″, then: # of risers = 30 ÷ 8 = 3.75 Rounding up gives 4 risers. Note that 5 risers may also work.

9. Number of Risers • Then the unit rise could be either 30″ ÷ 4 = 7 ½″ with 4 risers or 30″ ÷ 5 = 6″ with 5 risers

10. Determining Unit Run • Tread width may be found from the Rise/Run rule. • 17″ – 7 ½″ = between 9 ½″and 10 ½″ • 17 – 6 = between 11″and 12″ 9 ½″–10 ½″ 11″–12″ 6″ 7 ½″

11. Example • What are the possible unit rises and runs for a stair with a total rise of 102″?

12. Example • 102 ÷ 8 = 12.75  13 risers.

13. Example • Also 14 or possibly 15 risers.

14. Example • 102 ÷ 13 = 7.86  7 7/8″ unit rise.

15. Example • 17 – 7 7/8″ = between 9 1/8″ and 10 1/8″ unit run.

16. Example • 102 ÷ 14 = 7 5/16″ unit rise. • 17 – 7 5/16″ = 9 11/16″ and 10 11/16″ unit run.

17. Example • 102 ÷ 15 = 6 13/16″ unit rise. • 17 – 6 13/16″ = 10 3/16″ and 11 3/16″ unit run.

18. Design • Deciding which to use depends on the intended use and available total run. • 7 7/8″ steep • 7 5/16″ medium • 6 13/16″ gentle • Check local building codes for more guidance.

19. Conclusion • Stairs have a rise and run. • Unit rise = total rise ÷ # of risers. • Unit run may be found using Rise + Run = between 17″ 18″

More Related