historical Preservation

Cultural Heritage with LambertsGlas®

Preserve - Complement - Protect
From the point of view of monument preservation, the restoration with the window glass manufactured according to the original process is the only safe and correct way!

Preserve - Complement - Protect
From the point of view of monument preservation, the restoration with the window glass manufactured according to the original process is the only safe and correct way!

Protect the past
Shaping the future

Mouth-blown window glass

As an essential facade component, windows and doors shape the character of a historic building like no other component. Glass plays a decisive role in this.
Mouth-blown window glass is still manufactured today using traditional craftsmanship and has been the predominant type of glass for transparent window glazing for centuries.

With its slightly moving surface as well as bubbles and streaks, mouth-blown window glass is not only a valuable testimony to the time of its construction.

Its special handcrafted character has a decisive influence on the authentic overall appearance of historical facades and interiors.

Depending on the time of origin and the production site, historic hand-blown window glass can have different characteristics. 

In order to preserve the original impression and to be able to complement it faithfully 

mouth-blown flat glass is available in different variants. 

The traditional method of our hand-blown flat glass production was recognised and awarded UNESCO Intangible World Cultural Heritage status in 2023.

This honour underlines the importance of our craft in world culture and is a testament to our dedication to preserving traditional manufacturing methods.

restauro® Classic 3mm

Mouth-blown window glass with a vividly moving glass surface and stronger distortions in the transparency

    restauro® Light

    Mouth-blown window glass with a smooth movement in the glass surface and slight distortion in the view through

      restauro® Extra

      Mouth-blown window glass with more noticeable traces of the handicraft
      such as tool marks or an increased occurrence of streaks and gisp (accumulation of tiny air bubbles).
      Available in the variants restauro® Classic Extra 3mm and restauro® Light Extra 2mm

        restauro® Forest Glass (Waldglas)

        Mouth-blown window glass with light coloring
        Available in the variants restauro® Classic 3mm, restauro® Light 2mm and restauro® Extra

          Technical processing of mouth-blown window glass

          Energy efficiency and living comfort are increasingly becoming the focus of renovation measures in listed buildings. Thermal insulation, burglary protection and protection against noise pollution and vandalism are the central issues here. 

          Windows and glazing play an important role in this context.
          They require particularly sensitive handling so that the authentic character of historic window glass and the stylistic unity of glazing, window frame and facade are not lost

          Hand-blown window glass can be processed into insulating glass and laminated glass.
          In addition, mouth-blown window glass can also be tempered (toughened).

          restauro® as insulating glass

            restauro® laminated glass

              restauro® thermally toughened

                The technical processing of hand-blown window glass combines modern glass technology with traditional craftsmanship.

                UV and infrared protection with hand-blown window glass

                Light protection is one of the core topics in preventive conservation.

                Historically valuable objects, furniture and room furnishings are under the constant influence of daylight and are thus exposed to the damaging effects of UV and infrared radiation.

                UV rays cause color changes in sensitive materials and can destroy entire material structures.

                Due to their thermal effect, infrared rays lead to expansion and contraction movements in the image carrier, especially in the case of constant temperature changes. The consequences are stresses and cracks as well as flaking in the painting layers.

                Radiation penetration into interior spaces is particularly strong through window openings. Simple glass hardly offers any protection here - special light protection glass is required.

                restauro® UV

                  restauro® IR

                    With restauro®UV and restauro®IR, two special glasses are available for the modern preservation of historical monuments, in which the experience of a craft technique that is many centuries old and the technical know-how of the present are reflected.

                    The two mouth-blown special glasses have a UV and IR protection filter built directly into the glass structure and thus guarantee light protection for an unlimited period of time.

                    Mouth-blown special glasses for restoration

                    Over the centuries, a number of special shapes have evolved for closing window openings. The most common special shapes found in architectural monuments are Genuine Roundels, Plate Discs and Crown Bullions.

                    Over the centuries, a number of special shapes have evolved for closing window openings. The most common special shapes found in architectural monuments are Genuine Roundels, Plate Discs and Crown Bullions.

                    Genuine Roundels

                    Plate Discs

                    Crown Bullions

                    Handmade cast glass for the preservation of historical monuments

                    In addition to transparent window glass, glass with special structures is often found in architectural monuments. They are usually part of artistic designs and are found in the form of flat glass panels (table cathedral glass) or thicker glass plates (Dall glass).

                    Table cathedral glass and Dall glass (dalle de verre, glass slabs) plates are traditionally produced by hand casting.
                    When the hot glass mass comes into contact with the surface of the casting table or mold, the cloud-like structure (hammering) typical of this type of glass is formed. It is characterized by its irregular shape and traces of handicraft production. In addition, isolated bubbles give the glass its unmistakable character.

                    The unique structure of handmade cast glass provides privacy and at the same time full passage of daylight.

                    Handcrafted cast glass is available in a wide range of colors and can be custom made in special shapes.

                    Hand cast table cathedral glass

                      Hand cast dalle glass (glass slabs)

                        Quality
                        definitely
                        Quality
                        definitely