Historical structure: Rehabilitation of Homberg town wall successfully completed

• Spesa concludes extensive rehabilitation measures on historical town wall
• Damaged joints chiseled out, cleaned and then regrouted over an area of 400 m²
• 500 m of injection drilling, 250 m of masonry nails and 40 t of masonry grouting executed
• Small-diameter titanium piles installed as wall foundation

Homberg (Efze), Germany – The German town of Homberg on the Efze River looks back on an eventful history. Situated in North Hessen and first mentioned by official records in the year 1231, this was the site of the Homberg Synod – and thus the start of the Reformation in Hessen. Numerous historical structures attest to former glory. The ruins of the medieval Hohenburg Castle still preside over the old town center. Imposing town gates and towers, grand timbered houses and an almost fully preserved town wall complete the picture. But this significant heritage takes work to preserve.

Securing and rehabilitation

During the rehabilitation planning for one of the main streets, settlements were detected in the area of the hill castle. An assessment confirmed: The foundations of the city wall and neighboring street are connected through the soil strata and mutually influence one another. In order to preserve the historical town wall as part of the upcoming road construction activities, the town council of Homberg engaged a joint venture comprised of SPESA Spezialbau und Sanierung GmbH and the construction company Fröde GmbH & Co. KG. The task: developing and executing a rehabilitation concept including structural design and execution planning to secure the town wall over a length of roughly 100 m, along with structural reinforcement of Hersfelder Strasse.

Preserving the basic structure

“The range of services we performed was very wide,” emphasizes Silvio Stadach, Site Manager for Spesa. “The core work involved extensive masonry rehabilitation, including chiseling out the existing damaged joints, cleaning and then regrouting over an area of 400 m².” To further stabilize the natural stone wall, roughly 500 m of injection boreholes were executed, 250 m of masonry nails were installed along with 40 t of masonry grouting. Small-diameter bored piles were used for additional subsoil fixation. “As a foundation for the town wall, we inserted two different types of small- diameter titanium bored piles directly through the masonry up to a depth of 12 m,” continues Silvio Stadach. “In the area of the adjacent street, these small-diameter bored piles were installed as support structures.” In addition, the base of the wall structure was reinforced using shotcrete over the entire length of 100 m up to a depth of 0.80 m. The necessary excavation work for this task was also performed by SPESA Spezialbau und Sanierung GmbH.

Renewed splendor

“Our passion is the rehabilitation and preservation of historical structures,” remarks Silvio Stadach in conclusion. “However, deterioration had progressed too far in one area of roughly 80 m². Here we fully replaced the masonry down to a depth of 1 m.” The work began in August 2022 and was successfully completed in June 2024. Now the city walls of Homberg shine with renewed splendor and contribute to the special charm of the historical old town.