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Mechanically Engaged Overhead Glazing


Glass canopies come in two primary design philosophies - structurally glazed and mechanically engaged.

Mechanically Engaged

This design style of overhead glazing employs an aluminum extrusion that encapsulates a minimum of two edges that are then connected back to the primary structure. The Thermosash Alpha Glazing Suite (also refer Skylight and Atrium Glazing systems) can be used externally for canopies or internally for skylights as well as being an economical solution for factories, warehouses, hangers and grandstands, yet is a sophisticated and high performance solution for all high end skylight and sloped glazing applications.

The sophistication required of products used in overhead glazing can often be overlooked; the special design features required to cope with considerably higher water loadings, heat gain or loss (which introduces condensation) and in particular the risk associated with accommodating costly higher specification products (eg high performance laminated and insulated glass units) used to overcome these particular problems, without compromising their product warranties.

Due to potential exposure to high wind, seismic, snow, and live loads etc, it is neccesary for these types of systems to be specifically designed.

Product Features

  • Alpha glazing suite integrates with the Thermosash Delta Suite. 
  • Can be installed to a minimum slope of 3o (based on maximum glass deflect 
  • Integral drainage cavities.
  • Commercial glazing engagements to cope with higher wind loads.
  • Condensation control (where specified).
  • Thermal break.
  • Ability to provide a different colour from inside to outside.
  • Can accommodate all recognized glass thicknesses used in commerical glazing.
  • Special splicing and connection features critical for weathering.
  • Almost any type of glass can be incorporated including ceramic fritting to provide an element of solar shading corporate motif.
  • The Alpha range can incorporate opening sashes or banks of louvres - BMS operated if required.
  • The Alpha systems are dry glazed unless aesthetically otherwise required.
  • Bars are designed to accommodate co-extruded backing gaskets to minimise long term shrinkage problems. 
  • Glass is retained with gaskets fitted inside and out, primarily as a weather seal, but also to cushion against vibration and potential glass breakage.


We recommend using Masterspec 4251T Commercial Windows when specifying this suite type.

Surface Finishing 

Polyester powdercoat  - Both standard and special colours available.
Anodised - All anodised colours available - commercial grade 20 micron finish recommended.
PVF2 Flourocarbon finishes - Available on request. 

Performance / Testing

  • AS/NZS1170 (Structural Design Actions)
  • NZS4223 (Glazing in Buildings)
  • NZS/AS4284:2008 (Water / Air Pressure/ Air Leakage - Meets and exceeds minimum requirements)

Maximum Spanning Ability

Glass size and primary structure support is your only limitation. We can source your specific glass requirements to meet your projects needs.

Thermosash specifically engineers the best suite option for your project taking into consideration span, structural system, load imposed by glass thickness, wind & snow loading. The spanning ability will vary depending on the above. 

Thermosash Suites are recognized as having the largest spanning systems on the market due to our specific engineering capability and the customised nature of the work we complete.


The standard warranty is 5 years from the date of practical completion for these products. This covers workmanship and weather tightness, providing the subcontract includes fabrication, installation and glazing of all components. 

Downloads Available 

Please go to our resource section or click below for the relevant downloads: 
Masterspec 4251TS Commercial Windows