Landing Platform Framing for Steel Quarter-Turn Stairs

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A steel quarter-turn stair landing is framed by setting a rigid platform of beams and posts at the turn, sized to carry the design load and tied into the stair stringers at the correct points. The landing must be level, square to both flights, and fixed so it does not move under foot traffic. Exact member sizes and load values should always come from the structural engineer.

What a Quarter-Turn Landing Does

A quarter-turn stair changes direction by ninety degrees, and the intermediate landing is the platform where the two flights meet. The landing carries people walking across it, so its framing has to act as a small floor, not just a connection point. Before cutting any steel, confirm the landing position, the clear width of the stair, and how the flights will land on it.

Treat the landing as the anchor of the whole stair. If it is out of level or out of square, both flights will carry that error upward.

Choosing the Main Landing Beams

Most quarter-turn landings are framed with two primary beams running from a wall or structure to a corner post, with secondary joists spanning between them to support the decking or plate. The primary beams take the largest loads, so their section and depth are decided by the engineer based on span and design load.

Place primary beams where the flights bear on them
Keep spans as short as the layout allows
Use the same profile on both sides for even loading

Posts, Corners and Support Points

The corner where the two flights turn is the most stressed point of the landing. A post at this corner, properly base-plated and tied back to the floor or structure, prevents the platform from rocking. Support points should be placed directly under the beam ends, not in the middle of an unsupported span.

Check that every post is plumb before welding. A post that leans even slightly will push the landing out of level once the decking goes on.

Connecting the Landing to the Stair Flights

Where each flight meets the landing, the stringers should bear on a solid member or be fixed to a cleat welded to the landing frame. Avoid connections that depend only on a single bolt. Use full-depth welds or bolted connections with matching hardware, and make sure the step heights at the landing edge match the flight risers exactly.

Points to verify

Landing level matches the top step of each flight
Stringers fully supported at the connection
No gap or step at the landing edge

Decking, Edge Protection and Finish

The landing surface can be steel plate, checker plate, or a grating or tread system, depending on the use and the exposure. Plate should be fixed at enough points to prevent drumming or movement underfoot. The landing edges need guarding that matches the stair railing height and infill, so the platform is safe on all sides.

Finishing is usually hot-dip galvanizing or powder coating, applied after fabrication and before installation. Plan the finish early, since it affects tolerances and how the parts are handled.

Installation and Final Checks

Install the landing frame first, set and fix it, then bring in the flights. Check level and squareness at every stage, not only at the end. Once the stair is in, walk the landing and both flights to confirm there is no movement, no rattle and no trip hazard at any joint.

Compliance with the Israeli railing standard SI 1142 should be checked for guarding and dimensions, and any exact values confirmed with the engineer on the project.

Frequently asked questions

Why is a corner post needed on a quarter-turn landing?

The corner is where the stair changes direction, so it carries the most stress. A post there keeps the platform stable and stops it from rocking under use.

Can the landing be supported only from the wall?

Only if the wall structure is designed for the load and the span is short. In most cases a corner post is needed as well, and the engineer should confirm the arrangement.

How do I make sure the landing is level?

Check level on the beams before welding and again after the posts are fixed. Correct any error at the base plates rather than shimming the decking later.

Which standard applies to the railings on the landing?

The Israeli railing standard SI 1142 is the reference for guarding. Confirm the exact dimensions and infill requirements with the engineer for your project.

Common mistakes to avoid

The most common error is letting the landing go out of level or out of square before the flights are fitted, which throws off every step above it. Another is supporting the stringers on a single bolt instead of a fully supported connection.

Our recommendation

Set and check the landing frame to level and square before any welding, and confirm the design with the engineer before fabrication starts. Fixing errors at the landing is far cheaper than correcting the flights after installation.

Summary

A steel quarter-turn landing is a small framed platform that must be level, square and firmly supported at the turn and at each flight connection. Plan the framing, check it at every stage, and confirm exact values with the engineer.

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