Enter the opening diameter and the floor-to-floor height. The builder designs a custom welded spiral staircase to those exact dimensions, checks it against IRC, IBC, or OSHA live as you adjust, and hands you everything to fabricate it — the per-tread mark-out, the step set-out and cut list, full-scale templates, and shop drawings. Spin a sample below.
Punch in the opening diameter and the floor-to-floor height. Set the rotation and lock a step count, or let it solve the riser for you. The spiral builds itself in 3D to those exact dimensions.
Pick the code that governs the job — IRC residential, IBC commercial, or OSHA industrial. Every requirement turns green or red the instant you change a dimension: riser, walkline tread depth, headroom, clear width, baluster gap, handrail.
Pull the per-tread mark-out table, the step set-out (cut list, miters, picket marks), full-scale templates, the shop-drawing PDF, the BOM, and STL/OBJ — everything your shop needs to cut steel.
Pick the code edition — IRC 2024/2021, IBC, or OSHA, with your state's adoption built in — and the builder checks every spiral-stair requirement in real time. Each turns green or red the instant you change a dimension, so you catch the problem on screen, not on site:
Riser height (≤9½″, auto-solved from your floor-to-floor and step count) and tread depth at the 12″ walkline — ≥6¾″ for IRC, ≥7½″ for OSHA.
6′-6″ (78″) headroom at the landing and the ≥26″ clear walking width — the two things that fail most spirals.
Baluster gap and handrail height, checked against the same code so the whole assembly is compliant — not just the stringer.
REFERENCED TO IRC R311.7.10 · IBC 1011.10 · OSHA 1910.25
A custom spiral is a math problem wrapped in code constraints and expensive steel. The builder does the math, checks the code, and hands you the set-out — so a four-figure stair gets built right the first time.
The live overlay catches a too-tall riser or a tight walkline before you cut a single piece of steel. Quote and build knowing it passes inspection — IRC, IBC, or OSHA, whichever governs the job.
No failed inspectionsThe mark-out table gives per-tread sweep, riser, and cumulative stringer measurements. The verify checklist highlights each dimension on the model so you confirm it before the grinder ever comes out.
No re-cutsNo two openings are the same. Enter the customer's floor-to-floor and diameter and the whole staircase re-solves — treads, rotation, balusters, handrail — to fit that exact stairwell.
Truly parametricThe built-in quote builder prices the job off the real geometry and material take-off — so your number is right before you commit to the steel.
Accurate quotesSame 3D engine, on fences. The builder behind this spiral also renders an interactive model of your customer's fence, right inside their quote — spin, zoom, and a layer-by-layer build.
See the 3D Fence Viewer →Custom geometry, live code compliance, and shop-ready outputs — from the measurements you already have. Start free, no credit card.
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