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741 Dangerous glass infill panels on balustrade

Report ID: 741

Published: Newsletter No 53 - January 2019

Report Overview

A reporter expressed their concern about the structural stability of cantilever glass infill panels between a steel post and hand rail balustrade system at a high-level apartment block.

Report Content

A reporter expressed the following concerns about the structural stability of cantilever glass infill panels between a steel post and hand rail balustrade system at a high-level apartment block:

  1. The glass infill panels are set in to a mastic filled channel at the base which in places is deteriorating;
  2. Some infill panels are laminated, and some are non-laminated;
  3. The steel post and handrail balustrade system is not connected to the glass infill panels.

According to the reporter, in the event of a failure at the base, there is no secondary fixity to prevent complete failure of the glass sheet. The height of the apartment means that patio furniture can get blown right round three sides of the block of flats by wind. In the event of impact from the furniture, the non-laminated glass could shatter.

The reporter feels that all the non-laminated sheets of glass need to be replaced with laminated and a secondary top fixing bar in stainless steel added to exploit the existing post and rail system to hold the top of all the glass sheets given what appears to be the deterioration of the single base fixing.

Remedial work was undertaken to fix the top edges of the glass sheets to the hand rail on flats with the same detail.


Safety at height is a major concern and should always be in the forefront of the mind of a designer of external components in tall structures.

Here, the glass simply cantilevers from a mastic filled channel at the base which is not a robust detail, and does not provide safety either for residents or passers-by.

Cantilevers always require care and glass cantilevers particularly so. The risk is that if the glass breaks from impact then; firstly, there would be a large gap below the balustrade rail though which someone could fall and, secondly glass shards or granules could fall on the ground below. Another possibility would be that a panel was dislodged outwards, without breaking, but with the same consequences.

Small changes to the design would have resulted in a much safer scenario and substantially reduced the risk. The usual procedure for a designer would be to consult the CWCT standards and guidelines for glazing, and the CIRIA Guide to Glazing at Height C632.

Glass is a specialist material that fails in a sudden fashion and any bespoke application should always be designed by someone with appropriate knowledge and experience. There should be discussion at the design stage to satisfy the requirements of CDM and to deal with residual risks.

There are a number of CROSS reports about balconies which can be accessed by going to www.structural-safety.org and entering ‘balcony’ in the Quick Search box. Entering ‘glass’ in a separate search gives examples of glazing related problems.


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View other CROSS reports published in Newsletter No. 53


Glass panel with no top restraint

Glass panel with restraint fitted

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