Restoration glass for a reconstructed city building

NEW: Haus zur Goldenen Waage, DomRömer project in Frankfurt am Main – Germany

Reconstruction of the “Haus zur Goldenen Waage” [House of the Golden Scales] is a highlight of the “DomRömer” urban building project in Frankfurt am Main. SCHOTT provided 390 restoration glass panes to give the Renaissance facade an authentic look.


The background

The city quarter located between Frankfurt’s cathedral [Dom] and city hall [Römer] was a vibrant space in the historic city center with opulent patrician houses, old-style side streets and picturesque courtyards – until its destruction the Second World War. To reclaim the quarter’s vibrancy for this modern metropolis on the river Main, a major urban planning project was established in 2007. From 2012 – 2018, an area in the historic old city covering 7000 m2 was to be reconstructed.

Among the 15 buildings to be restored is the Haus zur Goldenen Waage that had been the city’s most well-known tourist attraction (Markt 5). The core of the building is a timber-framed construction from the Middle Ages that had undergone reconstruction up to 1619 by its eventual owner, the wealthy spice trader and confectioner Abraham von Hameln. It received an opulent Renaissance facade and lavish timber framing and was crowned with a Rhenish waved gable.
Haus zur Goldenen Waage, DomRömer project in Frankfurt am Main – Germany with SCHOTT Restoration Glass

The task

The reconstruction of this historical, architectural jewel presented restoration challenges of the highest order. Historical photographs were used for the reconstruction particularly for the doors and windows with their partitions, glazing bars and decorative profiling, as well as for the historical metal fittings such as the hand-forged angled metal strips, hinges and window knobs.

Other features included special window constructions such as a French casement window for use as an escape. It appears as dual 4-sash windows separated by a solid roofing post.

A solution was required for the complete window and door glazing to recreate a coherent and authentic look. Further factors to be considered in selecting the glass included not only the needs of the restoration but also the requirements of modern construction and energy-saving.


The solution

The firm carrying out the work, Kramp & Kramp based in Lemgo, opted for restoration glass from SCHOTT for the glazing. The firm PaX constructed the windows and doors.
  • The exterior window panes of the new box windows used single-pane restoration glass.
  • The interior panes used triple glazed glass with corresponding thermal insulation (Ug=0.5 W/m²K) and the latest fittings technology.
For the glazing, SCHOTT’s TIKANA® restoration glass and RESTOVER® light was used. This glass is machine drawn using the traditional Fourcault process which, in contrast to float methods, intentionally results in irregular glass surfaces (longitudinal undulations) and thickness. This produces characteristics shared with the glass originating from the different epochs while also enabling a range of processing options to fulfill construction and financial constraints.

Choosing the right glass requires not only consideration of historical contexts but also how the building is going to be used in the future. The lightly structured glass products TIKANA® and RESTOVER® light were therefore chosen for the “Goldene Waage” project.

  • TIKANA® is otherwise particularly suitable for buildings in the Bauhaus style. Its slightly irregular surface blends harmoniously into classical modern buildings.
  • RESTOVER® resembles window glass manufactured at the turn of the century. Its small thickness allows easy installation in historical window frames and profiles. The portfolio is completed by the RESTOVER® light variant, whose surface is less structured and less similar to mouth-blown glass than the RESTOVER® plus variant.

    Translated with
A total of 390 panes of SCHOTT restoration glass, with a special s-form lead coating (Karniesblei), were used to cover a window area totaling 110 m2. This has given the facade a coherent look despite the use of modern insulated glazing on the interior panes. A special color tone was applied to the wooden surfaces as well as to some of the fittings to give the windows a highly impressive and unique appearance.

Download our Project Report