FAQ's SCHOTT Restoration Glasses

1. What are restoration glasses and how do they compare to normal window glass?
SCHOTT restoration glasses are specifically designed to offer accurate glazing solutions for historical buildings according to their date of origin. They offer the typical surface characteristics of different historical eras that can be integrated into the modern day requirements for insulated and laminated safety glasses.
Compared to normal window glass, SCHOTT Restoration Glass offers state of the art technology in a historically correct design.

2. What colour are SCHOTT Restoration Glasses?
SCHOTT Restoration Glasses are colourless and particularly low in iron oxide. They are therefore highly pure and do not have the "green tint" typically found in conventional float glass.  SCHOTT restoration glass has a high transmission of visible light making it ideal for glazing buildings where naturally bright internal conditions are important.

3. What are the differences between the different SCHOTT restoration glasses?
SCHOTT restoration glass has the typical tensile strength of the manufacturing process. In addition, they are - depending on the product - more or less distorted.
  • RESTOVER® light: slightly uneven surface
  • RESTOVER®: irregular surface, wavy and expressive
  • RESTOVER® plus: strongly structured surface with distinct waviness
  • GOETHEGLAS: full of character and irregular
  • TIKANA®: slight tearing stripes
SCHOTT recommends a sample of at least 500 mm x 500 mm sample glass for the correct glass selection. Please evaluate the optics in the reflection (external view) and in the transmission (internal view).
SCHOTT Restoration Glass in use

SCHOTT Restoration Glass in use

Production of SCHOTT restoration glass by machine up-draw process
Production of SCHOTT restoration glass by machine up-draw process
  1. preparation of batch
  2. fill-in of batch
  3. glass melting
  4. up-draw process
  5. cooling down
  6. edge cutting
4. How are SCHOTT Restoration Glasses manufactured?
SCHOTT Restoration Glasses are manufactured using the traditional Fourcault process. The glass is drawn vertically upwards from the liquid melt through a nozzle via a drawing shaft. At the end of the drawing shaft, the glass is cut to sheet size.
Certain variations in surface structures are also possible and permissible within a product/plate.

5. What does tensile strength mean?

By vertically pulling the glass mass through the nozzle, the glass becomes distorted in parallel to the direction of drawing. When viewing through the glass, this distortion is more noticeable if the glass is installed vertically as opposed to horizontally. Sampling is also recommended here.

6. Does SCHOTT restoration glasses have bubbles, knots, stones or similar?
Such glass characteristics are possible due to the melting conditions and are permissible within certain specifications. However, they do not protrude from the glass surface.

7. What are the maximum dimensions?
SCHOTT Restoration Glass can be manufactured up to a length of 2,900mm and is therefore suitable for many buildings from the gothic revival period, Victorian era, Edwardian era right through to art deco and postmodern architecture.