How to Lay Out Straight Stairs for an 8 ft Rise?
An 8 ft (96 in) floor-to-floor rise at the 7.75 in IRC maximum gives 13 risers at 7.38 in each โ comfortably under code. With 10-inch treads the run is about 10 ft and the stringer runs 12.7 ft. This guide shows the layout sequence carpenters use, including the comfort check and headroom trap.
Step-by-Step Takeoff
-
1
Measure exact floor-to-floor rise (finished floor to finished floor), here 96 in.
-
2
Risers: 96 รท 7.75 = 12.4 โ 13 risers at 96 รท 13 = 7.38 in.
-
3
Treads: 13 โ 1 = 12 treads ร 10 in = 120 in (10 ft) of run.
-
4
Check comfort: 2 ร 7.38 + 10 = 24.8 in (target 25โ27).
-
5
Stringer: โ(96ยฒ + 120ยฒ) = 153.7 in โ 12.8 ft โ verify headroom in the Stairs Calculator.
-
6
Cut one test stringer and dry-fit before cutting the rest; check headroom (80 in minimum) at every tread.
-
7
Confirm nosing overhang (3/4โ1.25 in) and handrail height (34โ38 in) before final fastening.
Guide FAQ
What is max riser height?
7.75 inches per IRC R311.7, with minimum 10-inch treads.
How much headroom do stairs need?
Minimum 6 ft 8 in (80 in) measured vertically from tread nosings.
How do I calculate stair stringer length?
Square the rise plus the run and take the root โ โ(96ยฒ + 120ยฒ) โ 12.8 ft here.
What is the 25-27 comfort rule?
Two risers plus one tread should total 25โ27 inches for a natural stride.
Can stairs turn with winders?
Yes, but winders need 6-inch minimum tread at the narrow end per code โ L-shaped layouts often fit better.
Related Guides
How Much Lumber for a 16ร20 Deck Frame?
Joists, beams, posts, decking board feet, and hardware for a 16x20 deck frame.
How Much Paint for a 12ร12 Room?
Gallons, primer, ceiling paint, and cost for walls plus ceiling with two coats in a 12x12 room.
How Many Drywall Sheets for a Bedroom?
Drywall sheets, screws, joint compound, and tape for a 12x12 room with 8 ft ceilings and two windows.