"No one can have failed to observe that frequently the floor folds in such a way that one part rises at a right angle to the plane of the floor, and then the next part places itself parallel to this plane, to give way to a new perpendicular…"

Julio Cortázar wrote this in his famous instructions on how to climb a staircase. What the author described so poetically are, in reality, two fundamental technical concepts that define our daily mobility: the tread and the riser.

What exactly are they?

Although they might sound like complex technical terms, these concepts are very simple to understand when we break down the movement:

  • The Tread (T): Imagine the place where you rest your foot on each step. This horizontal surface is the tread; it is the depth of the step that supports your weight.

  • The Riser (R): Now, visualize the vertical part of the step—the part that "rises" from one level to the next. This height is the riser, and it determines how much effort each step requires.

In essence, the tread gives you the space to step, and the riser determines how high you climb.

The Importance of Design: Why "just any" measurement won't do

At Kaitek Arquitectura, we understand that staircase design is a fundamental pillar of a space's functionality and aesthetics. It's not just about connecting levels; it's about guaranteeing:

  1. Comfort and Ergonomics: A well-dimensioned staircase allows for a fluid ascent. If the measurements are off, you get that feeling of a "short step" or a "heavy step," turning the journey into an exhausting task.

  2. Safety (and the psychology of the step): The human brain is incredibly efficient: after the first two steps, it automates the movement. If an architect wanted to play a movie villain, they would only need to design a staircase with a single step just one centimeter higher than the rest; a trip-up is practically guaranteed. This lack of uniformity is an invisible trap, which is why millimeter-precision is our priority.

  3. Regulations and Accessibility: Building codes (such as the CTE in Spain) are not a whim. They establish that the tread must be at least 28 cm and the riser should sit between 13 and 18.5 cm to ensure that anyone, regardless of their agility, can use it safely.

The Science Behind the Step: Blondel's Formula

For a staircase to feel "natural," architects use a golden rule from the 17th century that remains valid today. Blondel's Formula establishes the ideal relationship so that the body's rhythm isn't broken:

2×Riser (C) + Tread (H) = between 60 and 65 cm (ideally around 63–64 cm)

This equation seeks to replicate the average length of a human stride. When this balance is respected, the staircase stops being an obstacle and becomes an intuitive path.

stair - staircaise form

The Kaitek Seal: Quality in Every Step

At Kaitek Arquitectura, every project is unique. We don't just apply formulas; we consider the context:

  • Intended Use: A main staircase with high traffic isn't designed the same way as a service staircase or a private one in a single-family home.

  • Materials and Aesthetics: Wood, metal, or glass change the perception of the step. We play with elements like the "nosing" (the edge that overhangs) to gain tread surface without taking up more floor space.

  • Universal Accessibility: We design for the future, ensuring the transition between levels is gentle for all users.

Ultimately, tread and riser measurements are not mere technical data; they are the essence of a well-thought-out structure. They are the key to ensuring that, as Cortázar said, the act of climbing is a safe, comfortable, and harmonious transition.