Stringer layout for a 108 inch rise
Ensure your staircase design meets the IRC riser limit of 7.75 inches for a total rise of 108 inches. Learn about headroom requirements and more.
Formula SSC-2026.1
IRC check pass
Risers / treads
14 / 13
Riser inside 4 to 7.75 in
Exact riser
7 11/16 in
195.9 mm
Total run
11 ft 4 1/2 in
3,467 mm
Stringer length
14 ft 6 1/16 in
Order 16 ft 2x12
Incline
38.35°
Square 7 11/16 in rise · 10 1/2 in run
Stringers @ 16 in
3
Throat 5.03 in on a 2x12
Rise, run, and the incline are scaled from the live riser and tread. Framing-square gauges match the exact riser and the tread depth.
| Item | Net | Waste | Order | Unit price | Line total | Source Spec Material / Tool |
|---|---|---|---|---|---|---|
| 16 ft 2x12 | 15.15 ft cut | end cuts included | 3 boards | USD | $100.80 | Source Spec Material / Tool |
| Stringer delivery weight | 134 lb | — | 61 kg | 2.8 lb/ft planning weight | — | Source Spec Material / Tool |
Source links open a product search on the Amazon storefront for the selected currency. SiteSpecCalc may earn a commission. The link does not change the quantities above.
| Total rise | Risers | Exact riser | Treads | Run | 2x12 stock | Check |
|---|---|---|---|---|---|---|
| 9 ft 0 in | 14 | 7 11/16 in | 13 | 11 ft 4 1/2 in | 16 ft | Pass |
| 9 ft 6 in | 15 | 7 5/8 in | 14 | 12 ft 3 in | 18 ft | Pass |
Show the deterministic formula
Risers = round(total rise ÷ target rise). Exact riser = total rise ÷ risers, reported to the nearest 1/16 in and in millimeters. Treads = risers − 1. Total run = treads × tread depth.
Diagonal = hypotenuse of stringer rise and total run. A dropped header uses total rise minus landing thickness. Stock is the next 8, 10, 12, 14, 16, 18, 20, or 24 ft board.
Stringers = floor(width ÷ 16) + 1, with a minimum of 2. Throat ≈ 11.25 − (riser × tread) ÷ hypotenuse.
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Project: Stringer layout for a 108 inch rise
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This sheet is an estimate for ordering and layout discussion. It is not a sealed design. Confirm the quantities with a licensed local professional and the authority having jurisdiction before you buy or build.
Engineering notes
When designing a staircase with a total rise of 108 inches, it is essential to adhere to the International Residential Code (IRC) which limits riser heights to a maximum of 7.75 inches. This ensures safety and comfort for users.
Note that headroom calculations are not included in this assessment, but it is crucial to ensure adequate clearance for safe passage.
Code reference
IRC R311.7.5
Field questions
- What is the maximum riser height allowed by the IRC?
- The maximum riser height allowed by the IRC is 7.75 inches.
- How do I calculate the number of risers for a total rise of 108 inches?
- To calculate the number of risers, divide the total rise by the maximum riser height. For a total rise of 108 inches, you would divide 108 by 7.75, resulting in approximately 14 risers.
- Is headroom included in the riser calculation?
- No, headroom is not calculated in the riser height assessment, but it is important to ensure that there is sufficient clearance for safe use of the staircase.