Renovation, historical Chamber of Commerce, Hamburg

The Hamburg Chamber of Commerce was affected by moisture damage and cracks in the brickwork in the cellar vaults. The vaulted ceiling under the commercial library was particularly critical.

• The proximity to the Alster and the damp building ground led to persistent moisture penetration in the lower structure.
• The construction of the underground railway in 1912 caused post-construction settlement due to the lowering of the groundwater level, which led to tension in the masonry and structural weaknesses.
• Visible cracks and moisture penetration impaired the stability of the affected areas.
   

Despite these challenges, the building fabric was in a predominantly stable condition:

• Load-bearing components such as walls and pillars in the basement had cross-sections of approximately 1 meter.
• However, the vaulted ceilings, with thicknesses ranging from 11.5 cm to 24 cm, posed significant challenges for the renovation.
   

Measures implemented
WEBAC 1610 reactive injection resin was used to stabilize the masonry and provide lasting protection against moisture. This product was chosen for its high solidifying effect and suitable flowability at low pressures.
The renovation measures included:

• Drilling holes in the vault caps – either crosswise or centrally along the cracks
• Patching the drill channels with quick-setting cement to ensure controlled application of the material
• Low-pressure grouting with WEBAC 1610 to prevent the resin from migrating into the intermediate layer of sand and gravel above the ceiling
• Structural closure and solidification of existing cracks using the resin

The targeted use of WEBAC 1610 restored the static function of the vaulted ceilings and provided long-term protection for the historic fabric.