Office Building, New Cavendish Street

In light of offering an acceptable solution to the problem posed by building regulations, Architen Landrell was contracted to design, manufacture and install a diamond shaped ETFE cushion rooflight in the glass lined office atrium. Early on in the design process architects Sturgis Associates and contractors Faithdean chose ETFE as the most appropriate material due to its light weight nature and its high levels of light transmission. The load constraints of the existing structure meant that glass, the obvious alternative, was too heavy to be used and ETFE met and surpassed the structural requirements.

After the local planning authority highlighted the need for some form of smoke control, ETFE came into its own, bringing additional benefits to those already established. As it has a relatively low melting point (only 200 degrees) it can be effectively integrated into the fire safety system of a building in order to ventilate spaces which may otherwise be entirely enclosed.  Architen Landrell was asked to design and install the ETFE cushion along with an integral ‘hot wire’ system - a wire running around a section of the perimeter of the cushion which heats up on the flick of a switch and disintegrates the ETFE membrane.

Although now a fairly common element in ETFE roofing, in this instance, the hot wire system needed to be installed in an unusual V shape to be most effective – as something that had never been done before, it took and element of research and design to ensure it’s success, something which the Architen Landrell team took on with some excitement!

Smoke management was not the only challenge for the design and project management teams however. It was necessary to keep the arch profile within the height constraints imposed by the planning authority while also providing the maximum area for glazed louvre vents around the perimeter. This was achieved by careful design liaison between the Architen Landrell team, our engineers, the project design team and the louvre supplier. Although a complex design process, this resulted in a successful, workable solution.

Speaking about the finished rooflight Project Manager Clive Loebenstein-Peckham comments; “Although a challenge we worked hard to ensure we met all the requirements of the client and of the local authorities. The rooflight forms only a small part of the overall scheme but it is integral to the success of the building management system and it enhances the feel of the space below. The client and Architect as well as the residents of the apartments overlooking this installation have all commented on its low profile and clean lines”.