Six apartment buildings, each three storeys high, with the exception of one, and 88 apartments – from one-room apartments for single people to five-room apartments, in which families with three children also have plenty of space. There is also lots of greenery and an underground car park with 92 parking spaces. This is the new residential quarter in Utting am Ammersee in Upper Bavaria. It is currently being built on what is known as the Schmucker site, at the top of the state road that runs through the town. The name comes from an old farmstead on which the residential area is built.
What is special about the Schmucker site is that the settlement is being built almost entirely out of wood, or to be more precise: using a wood-hybrid construction method. Only the underground car park, the basement and the elevator shafts of the buildings are made of concrete. Everything else – the inner walls of the apartments and the partitions between them, but also the facades – are prefabricated wooden elements. 12,000 square meters of solid wood panels alone have been used for this. The interior and partition walls are planked with plasterboard and gypsum fiber boards, the facades are protected against wind and weather with roughly planed, glazed spruce wood. It looks a bit gray and not everyone in Uttingen liked it immediately.
In the architectural and construction scene, the Schmucker site is treated as a prime example of what can now be done in timber construction. This has to do with the climate crisis, which is also coming to a head in Bavaria. Wood is considered to be the climate-neutral building material par excellence. Or as the former mayor of Utting, Josef Lutzenberger, puts it: “Every piece of wood stores CO₂. Every piece of concrete, on the other hand, is CO₂ in the atmosphere.” The “green Joe”, as they call Lutzenberger am Ammersee, was mayor of Utting until 2020. He is the engine of the timber construction settlement on the Schmucker site.
Josef Lutzenberger is former mayor of Utting am Ammersee and father of the timber construction project on the Schmucker site.
(Photo: Alessandra Schellnegger)
The Schmucker site is also attracting attention in state politics. If Forest Minister Michaela Kaniber (CSU) has her way, the settlement should find as many imitators as possible throughout Bavaria as soon as possible. Kaniber recently went to Utting with Building Minister Christian Bernreiter (also CSU) to promote the Free State’s new timber construction subsidy program. “Wood is the raw and building material of the future,” says Kaniber. “Wood not only grows constantly and in sufficient quantities in the forests right on our doorstep. It also filters and permanently stores enormous amounts of CO₂ from the air.” More wood construction is more climate protection, is Kaniber’s and Bernreiter’s credo.
It was only a good 50 years ago that wood was an exotic building material. It was mainly used in the country – for stables, commercial buildings or other functional buildings, now and then for single-family houses, a kindergarten or schools. And there was always one or the other spectacular wooden solitaire. The stress ribbon bridge over the Main-Danube Canal, for example. The structure made of glued laminated timber swings almost 190 meters in length from Essing to the other bank of the waterway. “Around 1970, the timber construction rate was just eight percent,” says Professor Ulrich Grimminger, “that was the historical low.” That has changed a lot. Around a quarter of all new buildings in Bavaria are currently made of wood. “The proportion will continue to rise,” says Grimminger. “The end is far from reached.”
Grimminger, born in 1963, is a trained carpenter, completed a classic civil engineering degree at the TU Darmstadt in the 1980s, but soon switched to timber construction and can be considered a fervent advocate of building with wood. Today, Grimminger teaches at the Technical University of Rosenheim, which is considered a leader in wood technology and construction, at least in Bavaria. Anyone who asks Grimminger about his credo will get the answer from former Federal President Theodor Heuss: “Wood is just a monosyllabic word, but behind it lies a world full of fairy tales and miracles.”
The most important positive property of wood as a building material, also from Grimminger’s point of view: “It is climate-neutral.” One cubic meter of wood stores one ton of CO₂, is the central principle of the timber construction trailer. The other is: In the forests of Bavaria, one cubic meter of wood grows every second. In combination, this should express: Unlike concrete, cement, brick and steel, the production of which produces huge amounts of CO₂, wood is climate-friendly and available in abundance. In Grimminger’s words: “For a tree to grow, all it takes is the sun. As it grows, a tree absorbs CO₂ from the atmosphere. If we use trees that are ready to be harvested, the CO₂ remains stored in them for a long time.”
The stuff trees are made of: Thanks to technical progress, wooden buildings are on a par with conventional buildings in terms of fire protection and protection against water damage.
(Photo: Alessandra Schellnegger)
From Grimminger’s point of view, wood only has positive properties in other respects. Wood is extremely stable, resilient and comparatively light, its insulating properties are significantly better than those of other materials. “Furthermore, you can prefabricate facades, interior walls and other constructions and then just put them together on site,” says the engineer. “That saves a lot of construction time and is not as burdensome for the neighborhood as bricklaying work.” Although wooden buildings are somewhat more expensive than conventional ones, the rule of thumb for the difference is ten percent. But they are cheaper to maintain. As far as fire protection and protection against water damage are concerned, wooden buildings are on a par with conventional buildings thanks to technical progress.
Wooden buildings are no longer just popular in the countryside. But more and more often also in big cities. The Bavarian State Forests, for example, which manage the state forests in the Free State, built the widely acclaimed “house on stilts” with apartments for employees near their headquarters in Regensburg a few years ago. It is intended to promote urban building with wood. In Munich-Oberföhring there is a brand new “ecological model settlement” with up to seven-storey apartment buildings and a total of 566 apartments, plus supermarkets, shops and community facilities – all in timber construction.
Elsewhere they are further along. The “Ascent” has just been completed in Milwaukee, Wisconsin. At 86.6 meters and 25 floors, it is currently the world’s tallest wooden skyscraper. Shops, leisure facilities and a lobby are located on the lower six floors and apartments on the 19 floors. According to the architects, as much CO₂ is bound in the “Ascent” as 2,400 cars emit in a year. The “Ascent” is unlikely to hold the altitude record for long. In Switzerland and Australia, high-rise wooden buildings of around 100 meters high are to be erected soon.
Professor Werner Sobek also builds a lot with wood, currently in Stuttgart a quarter with 329 apartments for employees of the clinic in the state capital of Baden-Württemberg. Sobek, 69, is an architect and engineer, he founded the Institute for Lightweight Design and Construction at the University of Stuttgart and is one of the initiators of the German Sustainable Building Council. Like his Rosenheim colleague Grimminger, Sobek advocates a radical change in construction. However, he has a much more reserved view of wood as a building material – precisely because of the climate crisis, as he says.
The final work on the Schmucker site should be completed in the second quarter of 2023, but the first tenants should be able to move into the wooden houses as early as January.
(Photo: Alessandra Schellnegger)
From Sobek’s point of view, building with wood is not as sustainable as many people think. This has to do with the life cycle of trees. As young seedlings, they do not absorb as much CO₂ as during their optimal growth. In addition, trees are usually felled well before they reach their maximum age. According to Sobek, even if you immediately plant a young seedling for every tree that is felled, building with wood creates a so-called CO₂ binding gap in the forests. A young tree that grows back does not store as much CO₂ as its much older predecessor.
In addition, only a comparatively small proportion of a felled tree becomes timber. Sobek puts it at 25 to 30 percent. The oversized rest, including branches and bark, remains in the forest, is processed into firewood, goes to the paper industry and the like. All of these uses have one thing in common: They tend to be short-lived. Up to half of the CO₂ that is stored in the felled tree processed into timber escapes back into the atmosphere in a comparatively short time and fuels the climate crisis there. Sobek therefore vehemently advocates economical construction, regardless of the building material. In his words: “We have to minimize the use of materials.”
In the meantime, construction work on the Schmucker site in Utting is entering its final phase. The housing estate is scheduled for completion in the second quarter of 2023. The first tenants will be able to move in as early as January. The 88 apartments have long since been taken. When they advertised, the municipality received almost twice as many applications.