With almost unlimited design versatility, structural glazing has redefined modern architecture. The dream of architects and facade designers of creating a visual impression of a monolithic glass structure has finally come true, thanks to the use of either structural glazing or bolt fixing.
By the term “ structural glazing” we mean the technology of attaching a glass structure to the building structure, where structural glazing silicon sealant serves as the binding agent.
Depending on the construction methods applied, there are four kinds of structural glazing:
- two-sided systems- using a two-sided structural glazing technique, either the vertical or horizontal joints are adhered to the supporting structure;
- four-sided systems – when using a four-sided system, no mechanical retention is used for the facade panels;
- bonded fixing systems – in this system the bolts are fixed directly onto the glass via a circular structural silicon seal which acts as a fixing point;
- fin glazing systems – the fin glazing technique employs glass panes which run from the frame of the building, perpendicular to the facade, which is then bonded to the fins using specific structural silicon sealants.
Structural glazing can be supported, and then the dead weight of the panel is transferred by a suitable mechanical support; and is not supported, when the dead weight of the panel is transferred solely by an adhesive.
Sealants used in structural glazing have to meet the most stringent requirements for strength and durability. They have to be resistant to ultraviolet radiation and changing weather conditions. Final sealing of the assembled units is made with silicon sealants of similar characteristics to the structural sealants. Since large glass surfaces may cause problems of over-heating in summer and considerable heat losses in winter, designing glass facades is a task which requires expertise from architects and designers and experience on the part of the technical staff. Therefore, we must warn customers against commissioning haphazard people for mounting and fixing, as the results of this action become evident after a few years and the investor covers the costs.
Press-Glas is an acknowledged contractor for fi xing structural glazing with Dow Corning sealants.
Bolt fixing is a system for securing glazing to a load-bearing structure by means of steel bolts going through the glass and mounted in specially designed holes. Bolt fixing allows designers to create perfectly smooth and transparent glass surfaces making up facades which are virtually invisible barriers between the interior and the exterior space of a building. It imposes no limitations as regards the height of the building and gives the architects almost unlimi-ted design versatility thanks to the direct fixing of glass panes to a load-bearing structure. As with the structural glazing, bolt fixing can be used with a variety of glass types e.g. clear, low-emission, solar control – absorptive and reflective, as well as with a combination of glass types. Whatever glass type is used, however, it has to undergo heat treatment for greater resistance to thermal stresses.