A glass act

Baltimore Wharf, a landmark development in London’s Docklands, required balustrades that were stylish as well as affordable. Housebuilder & Developer reports on the successful results.

Glass balconies, once the prerogative of high-end hotels, have become a popular choice for developers. Around 7.5 per cent of all properties on the market now feature a balcony of some kind, along with 11 per cent of new properties in urban areas, with glass balustrading the favourite choice of enclosure.

Systems can range from fully frameless balustrades using laminated structural glass to steel posted systems. The frameless styles are both more desirable and more expensive, requiring thicker laminated glass, with fixings often recessed into the floor. Their weight and difficulty of installation often leads to compromise, including the use of steel posted systems featuring multiple posts, lugs or clamps. While these can often be attractive and functional, architects and buyers lean heavily towards the more minimalist, frameless style that does not inhibit the view.

An innovative engineering design, developed for the landmark Baltimore Wharf development in London’s Docklands, aimed to satisfy these aesthetic demands at a cost comparable with the cheaper options.

The development

Designed by architects Skidmore, Owings and Merrill Inc, Baltimore Wharf is a £150m mixed use development on theformer site of the London Arena, comprising private and affordable housing, retail, leisure and community facilities built by international developer, Ballymore Group. Phase One of the development comprised more than 600 apartments in five separate residential blocks.

As a key architectural feature of the buildings’ external facades, the design and installation of external balconies required a considered approach. Working closely with the architect and developer, the balustrading suppliers were asked to develop a bespoke solution to suit the exacting requirements of the multi-storey buildings and the £3m budget.

The architects originally wanted structural glass balustrades to sit on top of the building’s 377 steel balcony structures. As an alternative proposal, they were offered a brand new design of balustrading, using a slim aluminium handrail with no upright posts and enabling the use of thinner and lighter glass. The new design allowed the developers to achieve a similar aesthetic effect at a substantially lower cost. Not only are these clear glass balconies now a striking feature of the project, they also saved £500,000 on the original design.

The new balustrading system, christened ‘Hybrid’ by Surrey-based manufacturer Balconette, is built around complex internal geometry hidden within the handrail itself. For the balconies on the Baltimore Wharf development, it removed the need for any upright supporting pillars while still providing all the required strength and support and meeting all relevant Building Regulations.

Satisfying the architect’s original balcony design criteria – to present a perfectly flat front fascia to seamlessly fit the main steel and the glazing track – was fundamentally important. The new anodised aluminium handrail was finished in Royal Chrome to look like shiny stainless steel, with a matching lower track extrusion allowed for relatively simple fitting to the main steelwork. Structural stability was achieved by anchoring the ends of the handrail directly to window mullions using a special single stage cladding that clips on to the specially- designed lower track.

Clear structural glass was originally specified, but the new design required only 4 mm + 4 mm laminated glass to retain a clear view, without the need for posts.

An added advantage of the system, particularly for high-rise buildings, is that panel replacement, if needed, can be done quickly and safely from inside. Panels are supplied up to 1.2 metres in length for ease of transportation and installation.

Living space

Ballymore Group’s building envelope manager, Mark Jackson, commented that balconies are a desirable addition to apartments:

“As they create an additional, practical living space where occupants can sit outside and relax.

“The clean lines of the aluminium hand railing and glass panels create sharp-looking balconies that really enhance the external facades.”

According to Effi Wolff, managing director at Balconette, the company felt there was a gap between very expensive structural glass systems and the traditional posted balustrades. He comments:

“The research we have undertaken with consumers told us overwhelmingly that their reason for wanting a balcony was to enjoy the view, so it made sense to try and remove the obstructions.

“The engineering for the new system was developed in-house, with what is effectively a concealed cantilever construction running through the handrail. We decided early on that aluminium had important advantages over stainless steel – not only in terms of weight but also in terms of longevity. Even marine grade stainless steel begins to show corrosion after a few years, but aluminium is virtually immune.”

In addition to the 377 balconies, Balconette supplied a glass balustrade design for the scheme’s social housing element, replacing the original wrought iron concept.