2021 IRC R311.7.5.1
Residential riser height baseline
Baseline residential stair check for maximum riser height.
Flags riser height above 7.75 inches.International Code CouncilTrust center
StairSolver Source Library
Plain-English pages for the rules behind the report. Start with the homeowner question, then check the rule version, source citation, and boundary before treating any result as buildable.
Readable source ledger
Common stair questions, written for homeowners
These pages do not copy code books. They explain what StairSolver checks, which official source is referenced, and what still needs a local authority or qualified professional.
Tread depthAre 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.
Riser heightAre my stair risers too tall?A tall riser makes every step higher, which can make the stair harder to climb and can trigger baseline risk even when the stair looks simple.
HeadroomIs there enough headroom over the stairs?Headroom is the tightest overhead clearance along the stair path, and it often becomes the hidden problem in basements, attics, and remodels.
Opening lengthIs my stair opening long enough?A short ceiling or floor opening can make the stair path fail in the real room even when the rise/run math looks acceptable.
Landing spaceIs the landing space too tight?A landing is the flat space where the stair starts, ends, or turns; if it is too tight, the layout can create a planning or inspection conversation before work starts.
Report methodHow the report is generatedSee how inputs, stair geometry, baseline rules, source citations, and project questions become the free PDF reference packet.
Rule version
irc-baseline-2026-07-01
Every generated report stores this version with the user inputs, so old reports can be reproduced even when the rules evolve.
2021 IRC R311.7.5.2
Residential tread depth baseline
Baseline residential stair check for minimum tread depth.
Flags tread depth below 10 inches.International Code Council2021 IRC R311.7.2
Residential stair headroom baseline
Baseline residential stair check for minimum stairway headroom.
Flags headroom below 80 inches.International Code Council2021 IRC R311.7.2
Stair opening and headroom path check
Headroom has to be verified along the stair path; a short ceiling or floor opening is a planning red flag that needs layout confirmation.
Flags opening length shorter than the calculated stair run as a planning prompt, not a full headroom approval.International Code Council2021 IRC R311.7.1
Residential stair width baseline
Baseline residential stair check for clear stairway width.
Flags expected finished width below 36 inches.International Code Council2021 IRC R311.7.6
Residential landing baseline
Baseline residential stair check for top, bottom, or turning landing depth.
Flags provided landing depth below 36 inches.International Code Council2021 IRC R311.7.8 and R312
Handrail and guard verification
Handrail and guard details are separate inspection checks from rise/run math.
Used for contractor scope questions, not automatic compliance approval.International Code CouncilFTC home improvement contractor guidance
Permit and contractor responsibility
Consumer guidance recommends confirming contractor details, permits, and written terms before work starts.
Used to ask who confirms local permit and inspection requirements.Federal Trade CommissionFTC home improvement contractor guidance
Written scope and payment clarity
Consumer guidance supports getting project scope, materials, schedule, and payment terms in writing.
Used to flag vague proposal language and missing stair-specific details.Federal Trade Commission2021 IRC R311.7.10.1
Spiral stairway special rules
Spiral stairways are treated as a special stairway type rather than a normal straight stair shortcut.
Used to tell users to verify whether a spiral stair is allowed for their exact room use.International Code Council2021 IRC R311.7.11
Alternating-tread device special rules
Alternating-tread devices are limited-use stair devices that need local verification before they replace normal stairs.
Used to explain why a loft access shortcut cannot be assumed acceptable.International Code Council2021 IRC R311.7.12
Ship ladder special rules
Ship ladders are a special ladder-style access condition and are not a general full-stair replacement.
Used to prompt local confirmation for ladder-style access proposals.International Code CouncilResidential stairs technical bulletin example
Local amendment warning
State and local amendments can differ from the generic IRC baseline.
Used to explain why StairSolver reports say baseline risk rather than local code approval.New York Department of StatePlanning heuristic, not code
Stair steepness comfort heuristic
Flags steep layouts as a planning concern even when the concern is not itself a code citation.
Flags stair angles above 37 degrees as attention items.StairSolverOpen-source basis
Used as bounded components, not a copied product
StairSolver uses mature open-source where maturity matters and reimplements stair-specific geometry in our own TypeScript so the product stays auditable.
Used as the explicit baseline-rule layer for riser, tread, headroom, width, landing, and stair-angle checks.
GitHub maturity signal checked: about 3093 stars and 506 forks.Downloaded to .oss/stairway-calculator-pro and used as a geometry/cut-list reference for stringer length, cut angle, and layout marks.
Expert review
Review packet, not fake approval
Seed review packet is present; real expert review results must be collected before claiming expert validation.
20-50 reports90% or more of baseline red flags are judged reasonable, and no high-severity item is judged dangerously misleading.
95" floor-to-floor height, 86" available run, 36" width, 82" headroom.
home inspector: Does the report correctly warn that the layout needs more run, a landing, or another layout before construction?102" floor-to-floor height, 126" available run, 34" width, 76" headroom.
stair carpenter: Does the report make the headroom concern obvious enough before framing or cutting stringers?Proposal text says labor and materials included, standard stairs to code, with no riser/tread/headroom/permit detail.
general contractor: Does the report ask for the missing scope details a homeowner should request in writing?Value proof
How the report earns trust
We keep internal product metrics out of this public page. What matters to users is whether the reference packet is downloaded, used in a real project conversation, and helpful enough to reveal a risk they missed.
A user sees the live result and saves the source-cited PDF reference packet.
This tells us whether the planning artifact is useful enough to keep.A user downloads the generated packet after checking the measurements and warnings.
This tells us whether the report feels like a real deliverable, not just an on-screen toy.A user uses the generated questions when talking with a contractor, inspector, or project helper.
This tells us whether the report changes a real stair decision.A user discovers a stair risk they did not already know from the raw measurements.
This tells us whether the report is teaching something valuable without pretending to be local approval.A user with a difficult stair plan wants deeper review after seeing the baseline report.
This tells us whether advanced review should be explored later.