Real Wood in Interior Fit-Out: Oak, Walnut, Ash and How Wood Grows More Beautiful

Why real wood in interior fit-out is different

Real wood differs from decorative foils and printed surfaces in one decisive respect: it has grown. Every board and every sheet of veneer is unique, with its own grain, its own colour variation and its own small irregularities. That is not a flaw but the reason wood feels so warm.

At the same time, wood reacts to its surroundings. It takes up moisture and releases it, it changes colour under light, it picks up marks of use. Anyone who chooses wood chooses a material that changes along with the home. The joinery Tischlerkultur, founded in 1935 by Leopold Dobrohruschka, has worked with wood for three generations, and the most important lesson from that is: whoever understands wood plans with these changes rather than against them.

Wood is the only material in the house that you do not just look at but can watch growing older.

Whether a piece of furniture is built from solid wood or from veneered boards is a question in its own right, which we answer in detail in the article veneer or solid wood. Here we are concerned with the timber species themselves, and first of all with the one almost everybody asks about.

Oak: the reliable all-rounder

Oak is the most widely used wood in high-quality interior fit-out, and for good reason. It is hard, hard-wearing and easy to work. Its grain is distinct but not restless, and it tolerates very different finishes, from almost white oiled to deeply fumed.

Oak contains tannic acid. That has practical consequences: in contact with iron and moisture it can discolour dark. We therefore use fittings and screws suitable for oak and make sure no steel swarf is left on the surface. The same tannic acid makes fuming possible: the wood reacts with ammonia and darkens in the upper layers without any colour being applied.

Over time, oak under light becomes slightly warmer and darker, taking on a faint honey tone. Fumed oak changes less. Anyone who chooses a very pale oak should know that it will not stay that pale permanently, unless the finish contains light protection or a slight pigmentation.

Depending on the cut, oak shows a very different picture. In the so-called flat-sawn cut, arched, lively patterns appear. In rift-sawn or quarter-sawn cuts the growth rings run straight, and the fine, glossy medullary rays known as "mirrors" show up. For calm, large wardrobe fronts we often choose a straight cut. And if the room should feel darker and more collected?

Walnut: warm, dark and elegant

Walnut is the wood for rooms that should feel collected and warm. Its colour ranges from light brown to a deep chocolate, often with violet or grey nuances. In interior fit-out, American walnut is frequently used, which is more even. European walnut is rarer and usually more lively in its figure.

Walnut is somewhat softer than oak but hard-wearing in furniture making. The grain is fine and flowing, which makes it especially beautiful on large veneered surfaces. In libraries, dressing rooms and bedrooms it creates a calm that pale woods do not reach. Picture a bookcase wall in walnut on a winter evening, lit from below, the spines glowing against the dark wood. How a bookcase in walnut or oak is planned is described in the article on the home library.

In ageing, walnut behaves differently from oak: under light it tends to become paler and more golden brown, and the initially very dark areas even out. Many people see this as a gain, because the wood then looks softer and livelier. Anyone who wants to keep the dark tone should avoid hours of direct sunlight or choose a finish with UV protection.

Ash: pale, tough and lively

Ash is the paler counterpart of oak. Its grain is also pronounced, but the wood is lighter, almost cream-coloured, and therefore looks fresher. Ash is very tough and elastic, which is why it was traditionally used for tool handles and sports equipment. In interior fit-out this shows in robust edges and hard-wearing floors.

Under light, ash tends towards a slight yellow cast. With a suitable finish, such as an oil with pale pigment or a soap treatment, this effect can be softened. One variety is olive ash, in which dark, irregular heartwood zones produce a lively figure reminiscent of olive wood.

Compared with oak, ash is somewhat more sensitive to moisture. In bathrooms and at sinks we therefore use it only with a suitably protective finish and with care. So how do the three compare?

The three species compared

Besides these three there are other woods that we use depending on the project. Cherry darkens strongly and takes on a reddish tone; maple is very pale and even but yellows noticeably. Which species suits always depends on the room and the light.

That is why choosing from a photograph is risky. A tone that looks perfect on a screen can feel cold at your window, and a surface that is too delicate shows every mark for years. You live with that choice every day, and nobody sells you a second floor. Wood in a home also has to survive the seasons.

How wood moves: humidity and the Viennese climate

Wood takes up moisture from the air and releases it again. In doing so it swells and shrinks, far more across the grain than along it. Solid wood reacts more strongly than veneered boards, whose construction largely compensates for the movement.

In the Viennese climate, indoor humidity fluctuates strongly. In summer the air is often humid; in winter, heating dries it out. In many Altbau apartments the relative humidity falls well below 40 per cent in January. Then small joints can open in solid wood, parquet strips show gaps, and large tabletops can warp slightly.

These tips help you live with wood in a relaxed way:

• Keep an eye on the room climate: A relative humidity of about 40 to 60 per cent is often recommended. A simple hygrometer shows where you stand.
• Adapt the construction: Solid wood panels need room to move. Good joiners plan for this, for example with breadboard ends or floating fixings.
• Acclimatise the wood: Before installation, wood should be stored in the room for some time so that it adjusts to the climate. With floors this is especially important.
• Not directly against radiators: Solid wood parts standing right next to heat sources dry unevenly.

If you are planning wood for the floor, you will find more in the comparison flooring: parquet, natural stone, ceramic and terrazzo. The last decision is the finish.

Finishes: oil, lacquer or soap

The finish determines how wood feels, how it ages and how much care it needs. There is no single right finish, only one that suits your daily life.

1. Oiled wood feels natural and warm. The pores stay open, and the wood looks matt and alive. Small scratches can be repaired locally and re-oiled. In return the surface needs regular care, once to several times a year depending on use.
2. Hard-wax oil combines the look of oil with somewhat more resistance to stains. It is a good compromise for kitchens and tables.
3. Lacquered wood is more closed and easier to care for. Modern matt lacquers hardly look like lacquer any more. Larger damage is harder to repair locally, however, and often a whole surface has to be retreated.
4. Soaped wood is a traditional treatment that keeps especially pale woods pale. It feels velvety but needs regular refreshing.

For kitchen fronts that are touched a lot, we usually recommend lacquer or hard-wax oil. For tables and floors that are allowed to be lived on, often oil. You will find more on fronts under kitchen fronts compared, and on how we build kitchens with timber fronts on the page about fitted kitchens.

An oiled oak table with twenty years of marks of use is more beautiful than one that looks as it did on the first day.

Wood in the overall concept: one species or several?

With Clara and Martin a typical question arises: should the whole apartment be in one species of wood, or may there be several? Our experience: one main species creates calm, and a second can set accents. More than two quickly becomes restless, especially if they lie in the same field of view.

Clara and Martin decide on oak as the continuous wood, for the parquet and the kitchen fronts, and on walnut in the library and bedroom. The rooms with walnut lie behind doors, so both woods are rarely seen at the same time. How such a common thread is planned is described in the article the materials concept. We show floor-to-ceiling wardrobes in oak or walnut under fitted wardrobes.

The overall concept also includes the question of provenance. Wood from sustainably managed forests with traceable certification has become standard in high-quality interior fit-out. A piece of furniture that lasts thirty years is, moreover, more sustainable than one that is replaced after ten. More on this under sustainable means long-lasting. With us, one contact person accompanies the whole path, from the first sample on the table to the handover in your home.