Windows and doors: The openings that define a space
Window and door design in interior architecture is, for most people, an afterthought a category of "fittings" chosen near the end from a supplier's catalogue, sized to fit the holes the builder left. I see it the other way around. Windows and doors are not accessories you add to a room; they are the openings that decide how a room breathes, where the eye lands when you walk in, how light arrives, and how one space hands you to the next. Get the openings right and a plan feels inevitable. Get them wrong a door too low, a window off-centre, an opening too mean for the wall it sits in and no amount of beautiful furniture will settle the unease. The openings are the architecture. Everything else is what you put inside it.
This is a piece about treating windows and doors as the structural decisions they are, not the decorative ones they are usually mistaken for. At Yasmine B Design, where the studio works at both the structural and the decorative level, the position, proportion, and detailing of every opening is settled early, on the plan, long before anyone talks about handles or fabric. Because an opening is one of the few things in a home that is genuinely difficult to change later. Here is how I think about it.
Why openings matter more than their fittings
A wall does two jobs: it encloses, and it connects. The openings are where the second job happens. A window connects a room to the light and the world outside; a door connects one room to another, and the home to its entrance. The size, height, and placement of those openings set the entire character of a space before a single piece of furniture arrives.
Consider proportion. A door's height changes how generous a room feels as much as the ceiling does. Standard doors stop at around two metres because that is what is cheap and available — but in a room with real ceiling height, a standard door looks stunted, and the wall above it dead. Taller doors, run closer to the ceiling, lift the whole room and make the architecture feel intentional. The same is true of windows: a window's proportions, its head height, and its relationship to the wall around it decide whether a room feels composed or accidental. These are decisions about proportion and scale, not about product.
Placement matters just as much. A window centred on a wall, aligned with what sits beneath it, framing a particular view, does something a randomly positioned opening never will. A door placed to reveal the best of a room as you enter, rather than its back, changes the experience of arriving. None of this costs more than getting it wrong. It simply requires deciding it deliberately, on the plan, at the start.
Windows: designing the way light and the eye enter
The first thing a window does is bring in light, and so window design is inseparable from how a home handles natural light. The size and head height of a window decide how far daylight reaches into a room: a tall window pushes light deep; a low, wide one spreads it shallowly. Where a room is deep or single-aspect, the window strategy is the difference between a bright home and a gloomy one, and it has to be settled before walls are fixed.
The second thing a window does is frame. A window is a picture frame held up to the outside world, and what it frames is a design decision. I will often move or resize an opening so that it captures the one good view a tree, a rooftop, a slice of sky and excludes the parapet, the neighbour's gutter, the blank wall opposite. A modern window can be large and minimal, with slim sightlines that all but dissolve the boundary between inside and out; or it can be divided and detailed in a way that suits an older building. Neither is "more contemporary" than the other. The right window is the one that suits the building and the light, not the one that photographs as fashionable.
A window also has to work as well as it looks. It has to open for ventilation a sealed glass wall is a beautiful idea and a stuffy room and it has to perform for energy efficiency, because the glazing and frame you specify decide how much heat the home loses in winter and gains in summer. Double or triple glazing, the thermal break in the frame, the airtightness of the seal: these unglamorous specifications matter as much to how a room feels as the view does, and they are settled at the same time as the proportions, not bolted on afterwards.
And the third thing a window does is set a tone through its detailing. The depth of the reveal, the profile of the frame, the material timber, steel, the slimness of the glazing bars — these quiet details separate a window that feels built into the architecture from one that feels stuck on. A modern window with minimal sightlines reads very differently from a divided period one, and both can be right. In a period apartment, respecting the existing window form is usually both required by local rules and right by eye. In a contemporary space, the discipline is restraint: let the opening be generous and the frame disappear.
Interior doors: the rhythm of a home
If windows govern light, interior doors govern rhythm how you move through a home and how each room is revealed. The most common mistake in interior door design is treating every door as identical: the same height, the same leaf, the same hollow construction throughout. A home designed with attention varies its doors to suit what they do. The door to a principal room can be taller, heavier, more considered; the door to a cupboard can recede into the joinery and disappear entirely.
Height is the lever most people never touch. Tall interior doors run to two and a half metres, or right up to the ceiling instantly make a home feel more generous and more architectural, because they treat the opening as part of the wall's full height rather than a hole punched in its lower half. Where ceiling height allows, this single decision does more for a sense of quality than almost any finish. Width matters too: a door that is too narrow for the room it serves makes the space feel pinched, while a generous opening, or a pair of doors, makes a threshold feel like an event.
Then there is the question of whether a door should announce itself or hide. A beautifully made door, with the right ironmongery, is one of the few things in a home your hand touches every day, and it should feel good which is why door hardware is never an afterthought in our projects. But just as often the right move is the opposite: a flush, concealed door a hidden door, papered or panelled to match the wall that lets a room read as a calm, continuous surface with no visible interruption. A bedroom door can be substantial and reassuring; a hidden door to a study or a utility room can disappear completely. Knowing when a door should be a feature and when it should vanish is most of the craft.
Door styles, openings, and how rooms connect
Beyond the single door leaf lies the larger question of how rooms connect and here the choice of opening type shapes how a home lives. A standard hinged door is the default, but it is rarely the only option, and often not the best. Double doors, or a wide cased opening with no door at all, can link a sitting room and a dining room so they read as one generous space when open and two rooms when closed. Pocket and sliding doors, which slide into or along the wall, recover the floor area a swinging door wastes and are invaluable in tighter plans. Glazed internal doors and steel-framed partitions divide space without dividing light, letting one bright room lend daylight to a darker neighbour while keeping a degree of separation.
A glazed partition is often the most useful of all. Where a solid wall would darken a room and an open plan would lose all separation, a partition glazed, steel-framed, or part-solid — divides space while letting light and a sense of connection pass through. Good partition design is some of the most rewarding work we do, precisely because it solves two problems at once: it gives a room its own identity without sealing it into the dark.
The decision about which to use is a planning decision, not a style one. It depends on how the rooms are used, how much wall there is to receive a sliding leaf, whether light needs to pass through, and how the spaces should feel when open versus closed. A glazed partition between a kitchen and a hallway, a pair of tall doors between reception rooms, a concealed door to a study — each is the right answer to a specific question about how the home should connect and flow. The popular instinct is to choose a "door style" from a showroom; the architectural instinct is to choose an opening that solves the relationship between two spaces.
The front door and the entrance: the first opening of all
The most important opening in any home is the one you arrive through. The front door — the entrance door, and the threshold it opens into — sets the tone for everything beyond, and yet it is astonishing how often it is the last thing anyone thinks about. A front door should feel solid and considered in the hand; it should be generous enough to make arriving feel like an event rather than a squeeze; and it should open into a space that has been designed as a proper threshold, not a leftover corridor.
Choosing a front door is partly practical security, weather, insulation, the constraints of the building and, in apartments, the co-ownership rules that often govern what may be changed. But it is also the first statement the home makes. Whether the right answer is a discreet, beautifully detailed door that belongs to its building, or a bolder, more singular one, depends entirely on the architecture it sits in. What never works is treating it as a commodity. The opening you pass through every day, and the one your guests judge the home by, deserves more thought than the spare-room curtains.
Window treatments: finishing the opening without smothering it
A window is not finished when the glass goes in; it is finished by how it is dressed, and the window treatment is where many otherwise careful rooms go wrong. The principle I work to is simple: the treatment should serve the opening, not bury it. Curtains hung too low, on a pole barely wider than the frame, in a heavy fabric that crowds the glass, shrink both the window and the room. Hung high — close to the ceiling — and wide, so that when drawn back they clear the glass entirely, the same curtains make the window read as larger and the room as taller, and let in every bit of the light the window was designed to capture.
The right treatment also depends on what the window needs to do. A room flooded with sun wants something that diffuses and controls glare; a window framing a fine view may want almost nothing at all; a bedroom wants genuine darkness. Sheers, blinds, shutters, and curtains each answer a different brief, and the elegant solution is usually the most restrained one that does the job. A window treatment is the last gesture in the design of an opening — and like all last gestures, it should complete the thought, not compete with it.
Common questions about window and door design in interior architecture
What makes a good window design? A good window is sized and placed to do three things well: bring daylight deep into the room, frame a worthwhile view while excluding the rest, and sit in proportion to the wall and ceiling around it. The detailing frame profile, reveal depth, material should suit the building rather than chase a trend. In short, design the opening first; choose the product second.
How do you design interior doors well? Start with height and placement, not the catalogue. Where ceilings allow, taller doors make a home feel markedly more generous and architectural. Vary doors to suit their importance a considered, well-made door for principal rooms; a flush, concealed door where a wall should read as continuous. And treat the hardware as something your hand meets daily, because it is.
What are the main types of door opening? Hinged (single or double), sliding and pocket doors that recover floor space, wide cased openings with no door at all, and glazed or steel-framed partitions that divide space without blockig light. Each suits a different relationship between two rooms; the choice is a planning decision based on use, available wall, and whether light needs to pass through.
How do you choose a front door? Balance the practical security, insulation, weather, and any co-ownership or heritage rules that govern what you may change with the fact that it is the first statement your home makes. The right door belongs to its building and feels solid and generous in use. Treat the entrance behind it as a designed threshold, not a leftover space.
What is the best door and window combination? The best combination is the one that lets light and movement work together: glazed doors or partitions that pass daylight from a bright room to a darker one, openings aligned so the eye travels cleanly through the plan, and consistent proportions and detailing so windows and doors feel like one family of openings rather than unrelated products. Coherence across all the openings matters more than any single pairing.
Should interior doors match throughout the home? They should belong to the same family consistent in detailing, hardware, and language — but they need not be identical. Letting a principal door be taller or more substantial, and a cupboard door disappear into the joinery, is what gives a home hierarchy and calm at once.
The opening is the architecture. Everything else is what you put inside it.
At Yasmine B Design, we settle the windows and doors first their position, proportion, and detailing because they are the decisions a home is hardest to change later and the ones that quietly govern how it feels. Across Paris, the South of France, Dubai, and London, the studio's 360° approach means the same hands that plan where the light enters also choose the door you touch on the way in. Get the openings right, and the rooms almost design themselves.
Ready to begin? Send the studio a message at yb@yasmineb.design, or follow along on Instagram and the journal for the thinking behind the work, from the heart of Paris.