Precast concrete elements support ancient church portal

The Soest-based Lehde company, a specialist in reinforced concrete, provides Markus Madeia, the local stonemason and restorer, with customized products for the restoration of a 17th-century church portal made of green sandstone. Madeia, who has made a name for himself as specialist in artisanal preservation of historical buildings far beyond the boundaries of Soest over the last 18 years, is working in his workshop located in Berlingsen on the reconstruction of the portal of the historical monastery church in Attendorn.

„I was contacted by the landscape architect Klaus Schulze, who manages an urban planning project in Attendorn. Subsequently, we participated in the corresponding tender and won the contract,“ Madeia reports. In the most literal sense Schulze stumbled over the church portal. Because it was lying flat, in pieces, in front of the city hall in Attendorn. There it will find its place again after the restoration. This time, however, in an upright position.

Precast elements as backbone

But, until then, in the months to come, Madeia and his five staff members will have to connect the existing green sandstone elements with new elements and joining them accordingly. The reinforced concrete elements made by Lehde will be the backbone here. „We really fight for every stone. We intend to ensure that the age of the stones remains visible. Therefore, we do not turn the church portal into a brand-new Disneyland-like version, but we treat the old material as well as the new material very carefully.“ As a result, the old stone fragments are connected to the new blocks in a nearly invisible manner, with lines and reliefs being continued in the new parts by the stonemasons. Where joints occur, a special repair mortar is used so that the supplementary parts are hardly perceptible.

In places, where whole bricks are missing in the old masonry completely, new ones will be inserted. However, these new bricks mostly remain untreated. „In this way, we want to make clear that the new bricks originate from the 21st century and not from the 17th century,“ Madeia adds.

Fair-faced concrete on the back side

However, on the back side, the reinforced concrete structure made by Lehde will be clearly visible. Like a kind of door frame with jamb and upper cross beam, they provide a support to the green sandstones and – as it is common for supports of Lehde – they come with pedestals set in concrete and are inserted into the ground. The elements are 70 cm wide, 30 cm deep and up to 4 m high. „It‘s not a big deal for us,“ comments Johannes, general manager of Lehde. „But we can demonstrate once again, what is possible with concrete. Even if it is to ensure the stability of a church portal.“