Concrete Filled Steel Stairs vs Open Steel Treads: Engineer's Guide

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Concrete filled steel stairs offer better sound insulation, greater stiffness and a more solid feel underfoot, but they add significant weight and cost to the structure. Open steel treads are lighter, easier to install and let light and air pass through, though they transmit more impact noise and need careful detailing for comfort and safety.

What Each Stair Type Actually Is

Concrete filled steel stairs use steel stringers and pans or treads that are infilled with cast-in-place or precast concrete, creating a solid, monolithic step. Open steel treads are individual steel plates, grating or perforated sheets fixed to stringers, leaving the void between treads visible.

Both systems are built to measure in our factory, so the choice comes down to the structural and comfort requirements of the building rather than the basic manufacturing process.

Acoustic Performance

Impact and footfall noise is the most common complaint in multi-storey residential buildings. Concrete infill adds mass and damping, which reduces the transmission of impact sound between floors and along the staircase core.

Concrete filled steps: lower impact noise, less ringing
Open treads: footfall is more audible and resonant
Open treads can be improved with rubber isolation pads and acoustic detailing

For projects where neighbour noise is a concern, the acoustic benefit of infill is usually decisive.

Load, Stiffness and Vibration

Concrete infill increases the stiffness of each step and reduces the vibration felt when people walk on the stair. This is valuable in longer flights and in buildings where users may be sensitive to movement.

Open treads rely on the stringer and tread profile for stiffness. They can perform very well structurally when properly designed, but deflection and vibration limits should be checked by the structural engineer for the specific span, tread depth and expected live loads.

Weight and Structural Support

The dead load of concrete filled stairs is considerably higher than that of open steel treads. This affects the supporting structure, foundations and the connection points to walls or floors, and it must be included in the structural calculations from the start.

Open treads place far less load on the building, which makes them practical for retrofits, rooftop access, mezzanines and existing structures where added weight is a limiting factor.

Safety, Grip and Maintenance

Open treads allow dust, leaves and water to fall through, which keeps them cleaner and reduces slip risk on exterior routes. Perforated or serrated surfaces can improve grip further.

Concrete infill gives a continuous, even surface that is easy to finish with anti-slip inserts. Protective galvanizing or coatings should be specified for both types, especially in coastal or humid environments. Handrail and guard requirements follow the relevant Israeli standard, and exact dimensional values should be confirmed with the engineer.

Choosing Between the Two

Concrete filled stairs suit residential buildings where sound control and a solid feel matter most, while open treads suit lighter structures, outdoor access and designs where transparency is a priority.

Noise between units: favour concrete infill
Limited structural capacity: favour open treads
Visual lightness and daylight: favour open treads

Send us your drawings and site conditions and we will advise on the most suitable option.

Frequently asked questions

Are concrete filled steel stairs much quieter than open treads?

Generally yes. The added mass and damping of the concrete reduce impact and footfall noise. Open treads can be made quieter with isolation pads and careful detailing.

Do open steel treads need a special structure?

They need stringers and connections designed for the span and expected loads. The structural engineer should verify stiffness and deflection for each project.

Which option is better for an outdoor staircase?

Open treads are often preferred outdoors because water and debris drain through them. Both types should be hot-dip galvanized or properly coated for weather resistance.

Can open treads be retrofitted into an existing building?

Often yes, because they are lighter than concrete infill. The existing structure and connection points must be assessed before deciding.

Common mistakes to avoid

Choosing a staircase type based only on appearance or price without checking the building's load capacity and acoustic requirements. Leaving the weight of concrete infill out of the structural calculations.

Our recommendation

Decide early whether acoustic performance or weight is the controlling factor, then have the structural engineer check the chosen system against the actual span and loads before fabrication.

Summary

Concrete filled steel stairs give better sound control and stiffness, while open steel treads are lighter, more transparent and easier on the structure.

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