Back to source library

Tread depth

Are my stair treads too shallow?

A shallow tread means each step gives your foot less landing space, so the stair can feel steep and may become a baseline risk before construction starts.

The short answer

The current baseline flags tread depth below 10 inches.

StairSolver uses this as a baseline planning check. If the measurement crosses the threshold, the report explains what number triggered the flag and what to ask before building, buying, or approving a plan.

Report boundary

Baseline risk, not local approval.The local authority, inspector, engineer, or qualified stair professional still decides the final answer for the exact property.

Referenced article content

What the cited source says

This is a StairSolver summary of the cited source content, written in plain language so you can understand the rule before opening the official reference.

  • The cited IRC baseline treats tread depth as a minimum walking-surface check.
  • StairSolver turns that cited threshold into a live warning when the calculated tread depth falls below 10 inches.
  • The source supports a planning flag, but the final stair still needs local review for the exact project.

What StairSolver checks

Inputs used for this warning

  • calculated tread depth
  • available clear floor length
  • riser count

User input fields: floor-to-floor height, clear floor length.

Why it matters

What problem this prevents

  • The user may think the stair fits because the total height is correct, but the horizontal run can still force each tread too shallow.
  • This is one of the clearest reasons to ask for more run, a turn landing, or another layout before buying material or approving work.

What to ask before building

Questions generated from this risk

  1. Can this stair get more run, a landing, or another layout so the tread depth is not too shallow?
  2. Can the layout show the exact riser count, tread depth, and total run before any stringers are cut?

What this page cannot prove

Where the tool stops

  • It cannot say your local inspector will approve the stair.
  • It cannot replace a stamped drawing, structural review, or local amendment check.

Official source links

Check the original source if you need the authority trail

These links leave StairSolver. Use them when you want to verify the official citation, then come back to the calculator to test your dimensions.

2021 IRC R311.7.5.2

Baseline residential stair check for minimum tread depth.

International Code Council / irc-baseline-2026-07-01Open 2021 IRC R311.7.5.2