Living Room to Terrace: Step Outside Without a Second Thought

Why the transition to the terrace is more than a big door

Many projects begin with a wish for "more glass". That falls short. A wide glass front connects nothing on its own: it shows you the garden, but it does not invite you out.

Whether a transition works shows in how you move. Can you walk out barefoot with a cup of coffee without looking down? Does the door stay open all summer afternoon because inside and outside feel like one room? Do guests at dinner sit half in the living room and half on the terrace without anyone saying "outside" or "inside"?

We do not answer these questions with a product, but with the guiding question behind each of our projects: how do you want to live? For the W. family the answer was breakfast outdoors at weekends, children who shuttle between the sandpit and the living room, and summer evenings with friends where the kitchen stays at the centre of things. That leads to a very different plan from the sentence "We would like a lift-and-slide door."

Doing nothing has a cost counted in summers. The garden stays something you look at rather than live in, and the terrace becomes a place you pass instead of use. A door or threshold chosen in a hurry is hard to correct later, because floor, glass and drainage are tied together, and you cannot move one without opening the others.

A transition succeeds when you forget that you are crossing a boundary.

We describe in more detail how strongly the threshold shapes the feel of a room in our foundation article on room transitions and why the threshold matters more than the room. For the step outside, weather, water and sun come into play as well, and that makes the job technically more demanding. First, though, comes the place where wishes meet physics: the threshold.

The threshold: water, warmth and the question of centimetres

The threshold is where the wish and building physics meet most directly. The wish is clear: inside and outside at the same level, no ledge, nothing to trip over. Building physics says: rainwater that stands on the terrace or is driven against the façade must not run into the house.

The relevant standards therefore generally provide for the waterproofing at the door to be carried up above the level of the exterior surface. Reduced or almost threshold-free solutions are possible, but they call for additional measures. Typical ones are a drainage channel directly in front of the door, a fall in the terrace surface away from the house, and a canopy or recess that keeps off driving rain. Which version is permitted and sensible in a particular case, we clarify with the window fitter and the waterproofing contractor before we commit to a height.

In Austria, a threshold height of no more than 2 centimetres is the usual guide for accessible building. It is a good benchmark even for those who are not thinking about accessibility: you barely feel 2 centimetres underfoot, and a sloping floor track bridges them well.

What has to work together at the threshold

• Height of the interior floor, including screed and any underfloor heating
• Build-up of the terrace, that is waterproofing, falls, drainage and surface
• Position and cross-section of the drainage channel
• Construction of the door frame and its lower profile
• Thermal insulation in the plinth area, so that no cold edge forms inside
• Protection from driving rain by an overhanging roof, loggia or awning

In existing houses like the W. family's, the terrace often sits lower than the interior floor. There are then two routes: raise the terrace, for instance with a surface on adjustable pedestals, or design a deliberate, broad step that invites you to sit. Either can be right. The only wrong answer is the narrow, accidental step that nobody planned.

Picture a Sunday in May. The door is pushed back, the floor runs on unbroken from kitchen to terrace, and the children cross between sandpit and living room without once looking at their feet. The step has become a place to sit. Which raises the next question: what do you walk on?

The floor: same look, different requirements

The strongest effect on the visual link between inside and outside is a floor that seems to run straight through. When the joint of the living-room tile continues in the terrace slab, the eye reads both surfaces as one. You may know the principle from our piece on continuous flooring that creates a sense of space.

Inside and outside, however, make different demands. Outdoors a surface has to be frost-resistant, slip-resistant even when wet, and strong enough for furniture, planters and the occasional barbecue. Indoors, what counts is warmth underfoot, easy care and compatibility with underfloor heating.

Many ceramic manufacturers therefore offer the same surface in two versions: a thinner slab for indoors and a slab about 2 centimetres thick for outdoors, which can be laid loose on pedestals or in grit. The outdoor version usually has a slightly rougher texture. From two metres away you can hardly see the difference, underfoot you can feel it, and that is as it should be.

The direction of the joints is important. If the joint runs parallel to the glass front, the boundary is emphasised. If it runs at right angles to it, out into the garden, it pulls the eye outside. For the W. family that meant large-format slabs of 120 by 60 centimetres, laid towards the garden, with underfloor heating indoors and adjustable pedestals outdoors. And what do you look through on the way out? The glass itself.

The glazing: lift-and-slide door, folding system or fixed glazing

The type of glazing decides how far the room really opens. Three systems are most common in homes in Vienna and Lower Austria.

Lift-and-slide door. A sash is raised and slid in front of or behind a fixed panel. The opening is usually half as wide as the whole front, but large panes and slim profiles are possible. For most houses this is the best compromise between airtightness, ease of use and appearance.

Folding system. Several narrow leaves fold to the side like a concertina. The opening can reach almost the full width. When closed, however, you see considerably more frame, and the folded leaves need room that has to stay free inside or outside.

Minimal sliding systems. Very slim sight lines, in some cases with frames recessed into the floor and ceiling. Visually the most elegant solution, technically and financially the most demanding. Early coordination with the structural engineer and the façade design is worthwhile here.

A rule of thumb from our practice: consider how often the front will really stand fully open. If the answer is "on twenty evenings a year", a lift-and-slide door with a large fixed panel is often the calmer choice. If the house is lived in almost without a front all summer, a folding system can be right. But the more glass you open, the more sun comes in.

Sun protection and climate: the Viennese summer as a design parameter

Large areas of glass facing south and west bring in not only light but also heat. Summers in Vienna and the surrounding area have become noticeably hotter in recent years. A living room behind an unprotected glass front can become uncomfortably warm on a July afternoon.

External sun protection is clearly superior to internal, because it keeps the heat out before it passes through the glass. Venetian blinds with adjustable slats, vertical awnings, or a roof overhang that blocks the high summer sun and lets in the low winter sun are the proven means. A pergola with a louvred roof or planting adds an intermediate space that is neither fully inside nor fully outside.

For how a home feels, this intermediate space is often worth more than any extra square metre of glass. A covered area three to four metres deep directly in front of the living room extends the season, shelters you from the first shower and turns the terrace into a room. If you are already thinking about surface heating and cooling for the house, the article on heating and cooling through surfaces explains how this ties in with large glass fronts.

Imagine a July afternoon. The awning is down, the living room stays cool behind it, and the light on the table is soft. You sit at the end of the day half indoors and half out, and nobody could say which. Then someone says dinner is ready, and the question is how the food gets out there.

The best spot in the house is often the one that is only half indoors.

Thinking the kitchen outwards

In the W. family's house the kitchen was at the back of the living room, a good four metres from the terrace door. Every meal outside meant carrying. In the new concept the cooking island moved so that there is now a straight, unobstructed line between worktop and terrace. A tray now takes six steps, not twelve.

How kitchen, dining and living relate to each other is the subject of our piece on zones instead of rooms. For the step outside, one more zone is added: the terrace as an extension of the dining area. Some families go one step further and plan a second, small cooking spot in the open air. What an outdoor kitchen has to cope with in Viennese summers and winters is a topic of its own, involving frost, UV radiation and water supply. Worktops in ultra-compact material such as Dekton are popular there because they tolerate both sun and cold.

If the kitchen is being replanned anyway, it pays to think about the way outside from the very start. How we plan kitchens as part of the whole house is shown on our page about fitted kitchens. Our workshop, Tischlerkultur, has built in Vienna since 1935, and the kitchen is built as part of the house, not as a catalogue item. And when the sun goes down, who keeps the connection alive?

Light and furniture: how the link also works in the evening

By day, daylight connects inside and outside almost by itself. In the evening the balance tips. If the living room is brightly lit and the terrace is dark, the glass front becomes a mirror. You see yourself, not the garden.

The solution is exterior lighting that picks up the light from inside: the same colour temperature, around 2,700 to 3,000 kelvin, dimmable and in stages. A tree lit at the far end of the garden gives the eye a destination. A few low lights along the path keep the terrace legible in the dark. How light can connect or separate rooms is described in the article Light as a Transition.

Furnishing can connect too. A sofa with its back to the glass front cuts off the garden. A sofa set at an angle or across the window takes it in. Textiles that stay in the same colour family inside and out reinforce the effect. How curtains and rugs also calm the acoustics of a large glazed room you can read in the piece on textiles, acoustics and homeliness. All these decisions depend on one another. In what order do you take them?

How we approach an indoor-outdoor transition

Because threshold, floor, glass, sun protection, kitchen and light depend on one another, we plan them in a fixed order. That stops an early decision from making a later one impossible.

1. Understand daily life. When, how often and with whom will the terrace be used? In the morning, in the evening, with children, with guests, in winter?
2. Survey the existing building. Heights inside and outside, orientation, roof overhang, existing waterproofing, structure around the opening.
3. Set the height concept. Where does the finished floor sit inside, where outside, and how is it drained?
4. Choose the glazing. System, opening width, sight lines, coordination with the structural engineer and, where needed, the authorities.
5. Agree floor and materials. Series, format, joint pattern, slip resistance outdoors.
6. Plan sun protection and cover. External, controllable, integrated into the façade wherever possible.
7. Plan lighting and electrics. Exterior lights, sockets on the terrace, shared lighting scenes with the interior.
8. Coordinate the works. Window fitter, waterproofing contractor, tiler, electrician and joiner in the right sequence.

The last point is where projects most often fail. If the window fitter sets the frame before the heights of screed and terrace surface are fixed, the threshold is decided before anyone has thought about it. At Richard Atelier the coordination of trades rests with one contact person, and our own workshop, Tischlerkultur, handles the joinery. How a complete refurbishment proceeds is described in the article Redesigning a whole house. You will find examples of our work under References. Not sure which order suits your house? That is what the first conversation is for.