CSLB General Building (B)Site Work, Foundations and ConcreteMedium
A continuous footing is being constructed on a steeply sloped lot, requiring the footing to step down in elevation along its length. According to standard code provisions for stepped footings, what is the maximum slope (rise to run) typically permitted between steps?
- A1 vertical to 4 horizontal
- B1 vertical to 1 horizontal
- C2 vertical to 1 horizontal
- D1 vertical to 2 horizontal
Show answer & explanationAnswer & explanation
Correct answer: D. 1 vertical to 2 horizontal
Building codes limit stepped footings to a maximum slope of 1 foot of vertical rise for every 2 feet of horizontal run, keeping the footing from becoming too steep and unstable. This ensures adequate soil bearing contact and prevents differential settlement between steps.
Why the other options are wrong
- A. This is flatter than required and not the maximum limiting ratio used in code.
- B. Too steep — a 1:1 slope exceeds allowable step ratios and risks instability.
- C. This ratio is steeper than 1:1 and far exceeds allowable limits.
Stepped Footing Slope Limit
A code-based limit restricting the steepness of stepped footings on sloped terrain to no more than 1 foot of vertical rise per 2 feet of horizontal run.
- Maximum step slope is 1V:2H
- Used when a footing must follow a sloping grade
- Prevents excessive footing steepness and settlement issues
Memory trick: 'Two runs for every rise' keeps stepped footings from toppling.