Hubert Rietmann
– and the idea that changed everything

Earthy scents waft their way through the room, filling it with the aroma of fresh clay while a small portable radio plays quietly in the background. The window lets the last warm rays of sun of the year shine into the moulded brick workshop, a small but well-organised atelier at the heart of Hagemeister’s factory hall that is fondly referred to as the “moulded brick den” by its employees. This is where Hubert Rietmann feels right at home.

His hands are quick and nimble, skilfully using his tools to shape the soft material just the way he wants it. Every single one of his movements reflects the craftsmanship required to transform clay into something truly special.

Rietmann is a qualified fitter and has been working for Hagemeister for nearly 35 years. He started out as a machine operator and then began to produce customised and moulded clinker bricks by hand around 18 years ago, an area of expertise that he has continued to master right into the present day.

Bringing with us a well-deserved coffee for this brick-making expert, we visit Hubert Rietmann in his workshop to explore the history of a truly unique idea that was sparked on a sunny day at home in his garden:

“I live right on the outskirts of Coesfeld-Stevede,” he explains. “It’s a peaceful little hamlet where you can hear the birds twitter and observe them without being disturbed. I am a huge nature lover. I’ve been actively involved in water protection work for 35 years and recently also started to support bird protection activities. We’ve done a fair bit of work in my garden to provide nesting sites for the local birds.”  

In fact, it was when considering this need that Hubert Rietmann recognised a growing problem.


“I have always been concerned by the fact that the demolition of older buildings also results in the destruction of nesting places for birds and habitats for bats.
New modern buildings have a completely closed building envelope, and although this has its advantages, it unfortunately also means that they do not offer any places of refuge for such animals.
And given that the systems commonly available on the market, for example hanging nesting boxes or bat houses, have a huge impact on the aesthetics of a building’s façade, I thought about coming up with a solution that is integrated into the façade.” 

These considerations marked the birth of the clinker nesting brick. This clinker brick component can be easily built into the building façade while also acting as a breeding box for birds and a habitat for bats. It was designed to be seamlessly integrated into the façade so as not to disturb the overall aesthetics of the building.
Reaching a working prototype, however, was a long process involving a great deal of work. With a prime example of commitment at its best, Rietmann spent his spare time reading up on a wide variety of relevant topics.

“I quite simply read about everything – from the properties of nest entrances to the option of inspection flaps and even considering the possibility of a self-cleaning bat cave.” His invention also had to fulfil all the standards for facing bricks, which made the process even more complex.

After countless hours of tinkering and testing, he devised a prototype, which he then optimised in close cooperation with nature conservation organisations, ornithologists and bat experts. The final version of the clinker nesting brick was launched at the international trade fair for architecture, materials, systems, BAU, in Munich at the start of 2021. It was met with an extremely positive response, with both architects and nature conservation organisations showing a strong interest in the product.

“We are also being contacted by more and more interested parties from outside of Germany,” declares Rietmann proudly. “In the Netherlands, for example, they want to use the clinker nesting bricks specifically for great tits, which can help combat the spread of oak processionaries. We can also offer solutions for private customers – because the great thing about the clinker nesting brick modules is that they can also be retrofitted into existing façades. As a result, everyone can do their part in helping to support and promote species protection and biodiversity.” 

Hagemeister now offers six different clinker nesting brick models for a huge variety of bird and bat species. Each individual module can be individually customised in terms of its colour, structure, format and brick bond.
Once the order is submitted, each brick is lovingly handmade by – you guessed it – Hubert Rietmann himself.

“Although I only manage to complete three to four clinker nesting bricks per day, producing these modules is a job that I will never get tired of doing. I have put my heart and soul into this project and am delighted about every single clinker nesting brick I make.” And we are delighted to have such a dedicated employee who has helped us to improve our commitment to nature conservation and biodiversity.  

Thank you, Hubert!