A Facade in Shape – The STEIN, July 2025

Building design
It is an austere façade. A geometric cubature with large-format wall surfaces. Only a row of bull's-eye-like round windows breaks through the façade. But despite its monolithic-looking building envelope, the Heidelberg Congress Center is characterized by its tactile feel and liveliness. And it owes this to the sandstone used from the region. The external unity of the large building, designed by the renowned Basel architects Degelo Architekten, is due to its internal functionality. The Heidelberg Congress Center offers space for up to 3,800 people and can be flexibly adapted to different event formats. Cover: Achim Birnbaum

In our issue on facades, we showcase extraordinary exterior cladding made of natural stone. Among them is the facade of the Congress Center in Heidelberg, which—despite its monolithic appearance—is characterized by its tactile quality and vibrancy. This, in turn, is due to the regional sandstone used: Neckartäler Hartsandstein. At Stachus in Munich, a new building with cubist offsets has recently been elegantly integrated into the historic surroundings. The travertine facade of the new Königshof is a real asset to this location. Even in faraway Helsinki, the city center has gained in elegance. The world-famous Finlandia Hall has been given a new facade made of Laas marble.

There are plenty of good reasons to use natural stone on facades: natural stone is durable, environmentally friendly, visually appealing, and pays for itself through low maintenance costs and a long service life. And yet, according to expert estimates, the market share of natural stone facades in new construction is still well below five percent. But once the decision is made, it’s worth taking a closer look. Starting on page 6, we’ll take you on an exclusive site visit to Heidelberg to see Neckartal hard sandstone.

Less than five percent

The facade of the new Könighof at Munich’s Stachus is also a spectacular sight. With its elegant travertine cladding, the luxury hotel enhances the city center, visible from afar. You can read more about this starting on page 12. Today, Helsinki offers a special gem crafted from white Laas marble: the Finlandia Hall on the shores of Töölö Bay. This world-famous architectural icon by star architect Alvar Aalto had to undergo renovation. Find out why South Tyrolean Lasa Bianco was used and what construction challenges it faced in our report starting on page 22.

From Munich to Helsinki

We’ve already reported on how artificial intelligence can be used in the stonemasonry trade in issue 3/25 of STEIN. Now we’re taking a look at new smart tools for the design and planning of natural stone objects. Everything for the Craft You’ll find essential information about the possibilities and limitations of AI image generators starting on page 40. From July 5 through August 30, the exhibition “Rock your focus” awaits you in Sindelsdorf, Upper Bavaria. Stonemason and sculptor Manfred Dangl is showcasing his artwork there alongside a photographer. Together, they present STEIN in a completely new and surprising context. Our author Bärbel Daiber visited the exhibition and spoke with both artists—a must-read starting on page 48.

We hope you enjoy reading STEIN.

The STEIN Editorial Team Redaktion@stein-magazin.de

In our latest issue, 06/25, we take a closer look at a very special piece from the creative department of the Westphalian luxury kitchen manufacturer eggersmann . Read more about it here.

“Rock your focus”

In our special issue on facades, we showcase extraordinary exterior cladding made of natural stone. Among them is the “cladding” of the Congress Center in Heidelberg, which, despite its monolithic appearance, stands out for its tactile quality and vitality. This, in turn, is thanks to the regional sandstone used: Neckartal hard sandstone. At Stachus in Munich, a new building with cubist offsets has recently been elegantly integrated into the historic surroundings. The travertine facade of the new Königshof is a real asset to this location. Even in faraway Helsinki, the city center has gained in class. The world-famous Finlandia Hall has been given a new facade made of Laas marble. […]

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The rock garden – more environmentally friendly than expected

Building design
Rock garden, photo: Dragonhunter/Pixabay

Photo: Dragonhunter/Pixabay

The rock garden’s reputation precedes it: it torpedoes biodiversity, supports land sealing and harms the “city” ecosystem. Read on to find out why this is incorrect, why the difference between the terms rockery and rock garden is so important and what you can do to create an environmentally friendly rockery.

The rock garden’s reputation precedes it: it torpedoes biodiversity, supports land sealing and harms the “city” ecosystem. Here you can read why this is not correct, why the difference between the terms rockery and rock garden is so important and what you can do to create an environmentally friendly rockery.

It is considered the natural enemy of biodiversity: the rock garden or gravel garden. And yet they can be found in abundance in Germany’s cities – and above all in its suburbs and rural areas. Ulf Soltau in particular has brought the rock garden into the public eye. The biology graduate has been regularly posting new impressions of the so-called “gardens of horror” on his Facebook and Instagram accounts since February 2019. We have already reported on the gardens of horror here on G+L.de.

There you can see particularly ugly and therefore also quite impressive – supposed – rock garden examples. One “rock garden” stands out for its sheer barrenness, while the other “rock garden” reflects the full creativity of its designers. Here, the classic garden gnomes adorn the gray, small animal exhibitions amuse passing walkers or creatures from other worlds greet their owners when they come home.

Below we have compiled our current top ten gardens of horror.

Click here for the “Gardens of Horror” Instagram channel.

The rock garden at the center of a social conflict

However, the gardens of horror do not only take place in social networks. Ulf Soltau achieved a print media breakthrough with his book “Gardens of Horror”. He has since even published a second book, “Even more gardens of horror”. At the same time, the attention has led to actual changes in the building regulations of numerous local authorities. More and more local authorities are banning gravel gardens in new development plans.

For many people, the bans are important signs for the protection of species and against the increasing sealing of surfaces. Others see the ban on rock gardens and gravel gardens as an attack on their personal aesthetics and freedom of choice. They, the rock garden advocates, often opt for the gravel garden because of its supposed ease of maintenance and time savings. The rock garden has thus triggered a real social conflict in Germany.

The title “Noch mehr Gärten des Grauens” was published by Eichborn Verlag. You can order the book here.

For some years now, the rock garden has been surrounded by an extremely dubious reputation. However, this is not entirely true. Because the rock garden does not always have to be gray. First of all, a brief but important piece of information about the term “rock garden” itself. The examples shown above may be rock gardens. However, the type shown can be more accurately described as a “gravel rock garden” or “gravel garden”. Why is this so important? Well, while a correctly laid out rock garden can be an oasis of biodiversity, a gravel garden is – quite deliberately – the exact opposite.

The gravel garden: Only supposedly low-maintenance

So let’s first take a look at these gravel gardens. They are large areas covered with gravel, grit, pebbles or simply crushed stone, sometimes with decorative elements and sometimes with a few undemanding plants. The supposed ease of maintenance of such a gravel garden combined with its neat appearance is therefore the main motivation for those who create them.

Weeding, mowing the lawn, watering, spiders, ants and other insects – you hope to be able to save all this in the gravel garden in the long term. However, no matter how elaborately the gravel layer is separated from the subsoil by root barriers, the unavoidable entry of leaves, bird droppings and other organic material into the layer creates the best soil after just a few years, in which the first seedlings immediately begin to thrive. Over the years, mosses and algae also colonize those stones that are in the shade. To slow down this process, a gravel garden requires regular maintenance, for example with a leaf blower, high-pressure cleaner or scraper.

Ultimately, the process of renaturation cannot be stopped completely. The fissured surface of the gravel layer makes it practically impossible to remove all organic material from it every time during the cleaning process. Even with good maintenance, a gravel garden will no longer look as neat and clean as it initially did after ten years at the latest and, depending on the owner’s visual requirements, the gravel layer may need to be completely replaced and the root barrier renewed. If a gravel garden is not maintained at all, it may no longer be easily recognizable as such in less than three years.

Local authorities and federal states are increasingly banning gravel gardens

Gravel gardens are not only biologically largely lifeless areas. Due to their heat capacity and lack of evaporation, they also contribute to the heating and drying out of the urban climate. They also reflect sound to a greater extent than green spaces, making for a noisier city. Gravel surfaces are considered at least partially sealed in most municipalities due to their inadequate water absorption capacity. They are therefore subject to the obligation to pay rainwater charges. If the gravel garden is even separated from the ground by an impermeable layer of foil or concrete, it is fully sealed.

More and more municipalities are now imposing bans on gravel gardens for new development plans. Individual state governments also support this approach – including Baden-Württemberg, for example.

The rock garden as a biotope

Rock gardens created by skilled hands are structurally rich and species-diverse lean biotopes. They offer microclimates in which highly specialized plants, many of them from the Alpine region, feel at home.

There are several hundred species suitable for planting in rock gardens, which are characterized by their frugality and robustness. Some popular examples are blue cushion, cushion phlox, thyme, woolly cistus and gentian. In addition to a large number of insects that live in a near-natural rock garden, the best-known inhabitant of rock gardens is probably the strictly protected sand lizard.

You can find more information on particularly insect-friendly gardens (not just rock gardens) here.

Library in natural stone

Building design

Marco Cappelletti

In April, the Rotterdam office OMA inaugurated the Qatar National Library in Doha. The project connects four of the country’s institutions and is part of a new campus being built. Marble and travertine were used in the interior of the library. The Qatar National Library (QNL) brings together the book holdings of four of the country’s collections: the Doha University and Municipal Library, […]

In April, the Rotterdam office OMA inaugurated the Qatar National Library in Doha. The project connects four of the country’s institutions and is part of a new campus being built. Marble and travertine were used in the interior of the library.

The Qatar National Library (QNL) brings together the book holdings of four of the country’s collections: the Doha University and Doha Municipal Library, the country’s National Library and a historical collection of texts and manuscripts on Arab-Islamic civilization.

The National Library is part of a new “Education City” located on the outskirts of Qatar’s capital Doha – one of the country’s most important education and investment projects. OMA also designed the Qatar Foundation Headquarters and a research institute on the satellite campus of international universities and institutes.

More than one million books are stored in the city library alone – on an area of 42,000 square meters. The library is designed as a large foyer with spaces for reading. The shelves are an important element: like the walls and floors, they are made of white marble to create a unified design. The material comes from the Dutch company Solid Nature. Lighting, ventilation and a book return system are also integrated into the shelves.

The historical script collection is located in an area that is lowered by six meters and can be accessed separately from the outside. The autonomous space stands out visually thanks to the beige-colored travertine used to clad the entire walls. From the foyer, it is possible to look down as if onto an archaeological excavation site.

Folded box

On the upper foyer level, the various areas of the library are connected by a girderless bridge. This creates hubs that the architects see as communication points for the various institutions. Here there are separate rooms for conferences, exhibitions, reading and studying. Folding walls are intended to make the rooms flexible in use – the system was designed by Inside Outside, which was also responsible for the landscape planning.

From the outside, the building looks like a box that has been tilted by 45 degrees. Inside, visitors perceive the sloping walls as steps and thus as access to the books on the white marble shelves.