21A Interiors: The Art of Proportion and Calm in Istanbul
people • designers
21A Interiors is an Istanbul-based design studio led by Tuvana Serdaroğlu, working internationally across residential and retail projects. Each interior begins with a simple question: how should this space feel to live in? The studio’s approach is quietly precise - guided by proportion, natural materials, restrained palettes, and soft architectural gestures that hold a room together without announcing themselves. Light is treated as a spatial tool, shaping rhythm and mood as much as function. In this conversation, Serdaroğlu reflects on trust in the design process, the emotional intelligence of layout, and the subtle decisions that give a space its lasting presence.
Words: designeers
February 2026
WEBSITE: 21ainteriors.com
INSTAGRAM: @21ainteriors
DESIGNEERS
Could you tell us how your journey into interior design started?
Tuvana Serdaroglu
I sensed at an early age that design and drawing would always be part of my life. Growing up, I was often told that I looked at spaces and objects through a different lens, and over time that perspective began to shape my path.
Studying in London expanded the way I understood interiors and architecture, taking the way I perceive and define space to another level. It was there that I began to see interior design not just as aesthetics, but as a discipline rooted in proportion, atmosphere, and the way people inhabit space.
Over time, interior design became the place where observation, thought, and everyday life intersect. My relationship with space grew more intuitive, but also more conscious and layered.
DESIGNEERS
What do you think is the key to a successful interior design? And in your business in general?
Tuvana Serdaroglu
For me, successful interior design begins with trust. When clients trust the designer, creativity can truly surface. Every project (whether residential or retail) needs to be approached on its own terms, shaped by context rather than a fixed formula. Understanding the character of the space in depth is essential.
As the founder of 21A Interiors, I believe versatility and curiosity are fundamental. Exploring different disciplines, materials, and cultural references allows each project to develop its own identity.
From a business perspective, interior design requires consistency and confidence. Working with focus, trusting the process, and standing behind your decisions are key. At the same time, staying open to change is crucial. I travel frequently, attend design events, and continuously research new ideas to keep my perspective fresh and the studio’s work evolving.
DESIGNEERS
You are known for calm, proportion, and materiality. What’s the first decision that sets that tone - a plan move, a texture, a light temperature, a colour?
Tuvana Serdaroglu
For me, every project begins with the plan. If the organisation, proportions, and circulation are resolved correctly, the atmosphere follows naturally. A strong spatial framework allows everything else - materiality, light, texture - to fall into place with clarity.
Materials then shape the character of the interior. In residential projects, the focus is on belonging and comfort, creating a space that feels deeply connected to its user. In hospitality work, the identity may come through a stronger gesture, expressed in a defining material, a proportion shift, or a particular spatial rhythm.
All decisions evolve from that first clear move in the plan. Once the foundation is right, the tone becomes inevitable rather than forced.
DESIGNEERS
What’s a rule you secretly follow because it always makes a space feel better to live in?
Tuvana Serdaroglu
I always begin with inspiration and translate it into a moodboard. Before rules, layouts, or technical details, I need to see how ideas coexist visually, how materials, tones, and references relate to one another.
In residential interiors, understanding the client is essential. The more clearly I understand their habits and emotional connection to space, the more precise the design becomes. For restaurants, retail spaces, or offices, understanding the end user defines the starting point.
When the moodboard feels resolved, the rest unfolds naturally. The goal is not only to create a space that looks harmonious, but one that feels intuitive and effortless to inhabit.
DESIGNEERS
You say you don’t impose a signature style. So what is your signature - the invisible one?
Tuvana Serdaroglu
For me, a signature is not a repeated form or a recognisable aesthetic. It is the ability to respond precisely to context.
My signature lies in knowing when to stop — when a space has reached balance and does not need to be pushed further. When proportion, materiality, and light align correctly, the interior feels complete without explanation.
That quiet accuracy, that restraint, is where my signature appears.
“A strong interior should resist passing trends and remain relevant over time. When materials age well and gain character, a space evolves rather than fades.”
Tuvana Serdaroglu
DESIGNEERS
Describe your perfect palette without naming a colour.
Tuvana Serdaroglu
My ideal palette is quiet enough to let materials speak, and deliberate enough to create a point of focus when the space needs it. I like palettes that feel responsive rather than dominant: they hold proportion, support light, and allow texture to carry the emotion.
It’s less about decoration and more about balance, knowing when the palette should recede, and when it should gently shape the room’s rhythm.
DESIGNEERS
What’s the most underrated luxury in interiors right now - silence, weight, tactility, or time?
Tuvana Serdaroglu
For me, the most underrated luxury is time, or rather, how a space holds up over time. When material choices and design language are handled well, the result feels both original and timeless, which is the greatest luxury today.
A strong interior should resist passing trends. If materials age beautifully and gain character, the space evolves instead of fading. That ability to remain meaningful beyond trends is, for me, the true definition of luxury.
DESIGNEERS
Finish this sentence: “A room is successful when…” (and then tell us what most people get wrong about that).
Tuvana Serdaroglu
A room is successful when its layout is thoughtfully composed, and its details are carefully considered. What truly matters is how the person inside the space feels. Details support that feeling and give the space clarity and balance. Trying to achieve this through passing trends often leads to superficial results and unnecessary mistakes. A well-considered space creates a clear and immediate sense of comfort and confidence.
DESIGNEERS
Your design hero?
Tuvana Serdaroglu
Joseph Dirand - for his timeless restraint, disciplined sense of proportion, and his ability to create atmosphere through precision rather than excess.
DESIGNEERS
Your dream dinner guest?
Tuvana Serdaroglu
Bridget Riley. Her work fundamentally shaped the way I think about rhythm, perception, and how subtle shifts can transform spatial experience.
DESIGNEERS
Your favourite hotel in the world?
Tuvana Serdaroglu
Qasr Al Sarab Desert Resort by Anantara. The surreal vastness of the desert, and the way the architecture dissolves into the landscape, create a deeply immersive and atmospheric experience.
At the heart of 21A Interiors is an understanding that calm is not accidental, it is constructed through thoughtful planning, disciplined material choices, and quiet decisions that shape how a space is experienced.
In a world that often demands visual impact, Serdaroğlu’s interiors offer something rarer: confidence without excess, and atmosphere that lingers long after the first impression.
