The project of “Historically Correct Restoration Hoerder Dortmund Castle” has become a beacon of urban planning for the city of Dortmund.
Due to its history and location on the new Phoenix Lake, just off the inner city, the redevelopment was in the public eye. Adequate funding, with the necessary sensitivity to the original structure, was expected by all project participants to complete the entire project successfully.

The Challenge

The Hoerder Castle had experienced, in recent decades, different uses causing highly visible wear and tear. It was now the task of the Hetzel + Sponheuer GmbH & Co. KG to repair and restore the damaged surfaces so that the visibility of the applied materials exhibits no significant difference to the structure and surface of the existing building.

The Solution

Consultants, material suppliers and restorers of our “building network ” were involved early-on in the project to direct everything important into the project’s path. For the timely coordination of materials, colors and techniques with the historical preservation authority is a prerequisite for us to maintain uninterrupted, fast construction.

Basis for the restoration were damage claims and a restructuring plan. Plaster damage could be repaired, without compromising the existing historic structure. Our experts were able to retain the old plaster and still make a renewal. They were able, with the right equipment and a lot of skill, to finesse the adjacent areas with almost the same structure and thus ensure a homogenous overall appearance.

Condition before renovation

installation of spiral anchors

Due to extensive cracks in the facade surfaces, corresponding helical anchor systems with the associated system mortars were used. It was mainly on the material compatibility between existing and rehabilitation products for the new facade of the castle that permanently defies wind and weather. Thanks to the use of helical anchors, crack paths were fixed and the masonry stabilized. The movements of the walls could be significantly reduced by the high tensile strength and elasticity of the spiral anchors.

With the choice of materials were the recommendations of the WTA (Scientific Technical Work Group). We were able to gather the experience and expertise from a variety of application areas. Our Group has been for many years a member of the WTA and therefore has access to valuable information, especially when it comes to listed building renovations.