In the early years of my practice, a client once asked me whether it was possible to turn her home staircase into a decorative element. The question struck me, because it revealed a very common perception: the staircase as nothing more than a functional tool—perhaps shaped by the memory of apartment block staircases, cold and anonymous. She wasn’t used to the idea that a staircase could become a central feature of domestic life.
That conversation reminded me of a scene from the classic film The Seven Year Itch. In the apartment that separates the main house from the one rented to Marilyn Monroe, there is a bricked-up staircase: it has lost its function, but remains part of the setting, an element rich with symbolic and narrative meaning. It’s the perfect example of how a staircase, even when no longer connecting two floors, can still exist as a strong architectural and theatrical presence.
Since then, I’ve always believed that every staircase in a home has the potential to go beyond its function: it can be a sign, a narrative object, a vantage point that guides those who live in the house not only in movement, but also in perspective and imagination.
Why Interior Stairs Are More Than Just a Connection
Interior staircases are often the only vertical architectural feature in a home—the element that breaks the horizontality of domestic spaces and invites the eye to change direction. When we climb or descend a staircase, we enter a unique condition: for a moment, our body moves vertically, our gaze tilts upward or downward, much like when approaching a window and glimpsing the outside world. It’s a daily gesture, yet it carries a subtle disruption of domestic normality.
For this reason, staircases are never purely functional. They become bespoke design objects, capable of radically shaping spatial perception and, in some cases, achieving an iconic value comparable to that of a sculpture. Redesigning an interior staircase therefore means working not only with proportions and materials, but also with the very character of the house.
Regulations and Bureaucracy: What You Need to Know
Before envisioning light steel lines or sweeping wooden ramps, it’s essential to understand the rules governing staircase design. In Italy, the main references are D.M. June 14, 1989 No. 236—which establishes accessibility and safety criteria—and local building codes.
A key aspect in stair dimensioning is the relationship between riser (a) and tread (p), expressed by the traditional formula:
2a + p = 63 / 65 cm
Where does this formula come from?
It derives from the average human step length—the natural stride of an adult in motion. Ergonomic studies have shown that a comfortable and safe step measures about 63–65 cm, corresponding to the sum of two risers plus one tread:
- Riser (a): the vertical height of the step
- Tread (p): the horizontal depth of the step
When walking on a staircase, our foot covers two risers plus one tread, replicating the natural stride on flat ground. This proportion ensures comfort, safety, and smooth movement, avoiding steps that are too high or treads too short, which strain the leg and increase the risk of tripping.
Recommended values
For comfortable interior staircases, risers should range between 16–18 cm and treads between 27–30 cm. This proportion respects the human step formula and ensures a natural walk, even on steep or space-saving stairs.
Other important dimensional aspects include:
- Minimum width: in private homes, no less than 80 cm to allow safe passage.
- Railings and handrails: at least 90 cm high, sometimes up to 100 cm.
- Ramp development: overly long flights must be interrupted by landings every 10–13 steps, both for rest and safety.
Bureaucratic requirements and pre-calculated stairs
From a bureaucratic standpoint, remodeling or redesigning an interior staircase almost always requires a building permit:
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CILA (Comunicazione Inizio Lavori Asseverata) for non-structural interventions
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SCIA (Segnalazione Certificata di Inizio Attività) for more invasive modifications
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Structural calculations signed by an engineer in case of demolition or structural construction, to be filed with the Civil Engineering Office
However, there are pre-calculated or prefabricated staircases already designed and certified by the manufacturer. These do not require structural calculations, making installation quicker and easier. Their main limitations lie in standard dimensions and limited aesthetic customization: risers and treads are often fixed, and design options are fewer compared to a fully bespoke staircase.
Space-Saving Stairs: Smart Solutions for Small Homes
Not every home offers the space for a traditional staircase. In small apartments or for connecting accessory areas such as mezzanines—where every square meter counts—compact, ingenious solutions are needed.
One of the most notable is the alternating tread staircase, also known as the miner’s stair. Steps are staggered to alternately accommodate the right and left foot, reducing the overall footprint without fully sacrificing comfort. This type is ideal for secondary connections, small studies, attics, or mezzanines.
Other space-saving staircase options include:
- Spiral staircases: compact in footprint but inconvenient for moving bulky objects.
- Modular metal stairs: lightweight, customizable, and easy to install.
While these solutions don’t always meet full accessibility standards, they are permitted as secondary connections and often represent the only practical choice in tight spaces.
Construction Systems: Materials and Styles
The choice of material for an interior staircase is not just aesthetic—it impacts durability, maintenance, and cost.
- Wood: warm and natural, easily customizable, but requires regular maintenance—especially softer woods.
- Steel or iron: strong and lightweight, often combined with wood or glass steps. They allow for almost unlimited design freedom, from minimalist lines to dramatic structures.
- Concrete: the most robust and permanent solution. Concrete stairs become part of the building’s structure and can be finished with ceramic, stone, wood, or resin, transforming into a solid, long-lasting architectural feature.
The choice depends heavily on context: independent houses allow for a wider range of solutions, while apartments benefit from lighter structures, easier to assemble and less invasive.
Interior Staircase Remodeling Costs
Redesigning an interior staircase is a significant investment, varying according to type, materials, and project complexity. Indicative costs include:
- Modular space-saving metal staircase: €2,000–5,000
- Custom wooden staircase: €4,000–10,000, depending on wood type and finishes
- Contemporary steel staircase: €6,000–12,000
- Concrete staircase with finish: €7,000–15,000
To these figures must be added technical expenses: designer fees, permits, and structural calculations. In general, a staircase redesign project ranges from €3,000 to €15,000, but for iconic, design-driven solutions, the budget can rise significantly.
The Staircase as a Domestic Sculpture
An interior staircase is not just a passage—it is an architectural object with a unique scenic power.
For this reason, a staircase can become a bespoke design piece, tailored to the home and its inhabitants. It may be discreet and almost invisible, or monumental and sculptural. In any case, it is an opportunity to express identity and transform a functional need into a feature of renewal.
Redesigning a staircase therefore means creating much more than a vertical connection: it means introducing an element that enriches domestic life, like a sculpture to be lived in, guiding the gaze, gestures, and paths of those who inhabit the home.
About Riusourbano
Every article you read here comes from real project experience.
We are architects – our practice is Architetti Gianuario Ustica – and through Riusourbano we share our way of living, thinking, and transforming space.If you have an idea in mind, or a place you’d like to rethink, we’re ready to listen.
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