Celebrating the Design and Installation Team at Lucent W1

LUCENT W1 is one of the most complex and intricate city block refurbishments ever, and it is all tied together with a folding roofscape of slate, zinc and hot melt. The roof knits together several historic facades and incorporates 22 terraces and a rooftop restaurant, all constrained by complex height and viewing restrictions.

This roof was designed by SIG Design and Technology, working in partnership with their DATAC accredited roofing contractor E J Roberts and main contractor Wates Group to produce one of the most interesting and complex roofs in the city of London.

A 360 flyover of the completed roofscape at Lucent W1. Video: Wates Group

Collaborative Design

When Fletcher Priest Architects secured planning permission to bring together 13 different buildings behind the Piccadilly Circus Lights for developer Landsec, they envisaged that the roof which tied all the buildings together would be a steel structure covered in faceted ceramic tiles. In order to meet the constraints of budget and fire performance, the design had to change, and Wates Group brought in their long-standing roofing partner SIG Design and Technology (shortly to rebrand to Accuroof) to rethink the design from scratch, whilst meeting the architect’s original design intent.

Wates were able to confidently select SIG Design and Technology for the design and supply, and E J Roberts Limited, one of our DATAC contractors, as their specialist contractor, knowing that they would be able to meet all the requirements of such a complex project and had experience working together on multi-material roofs.

E J Roberts is a London based multi-disciplinary roofing contractor with over sixty years’ experience including in hot melt, felt, slate, tiling, hard metals, lead and heritage projects. Their slaters alone who worked on the project have over 100 years’ joint experience in slating.

SIG Design and Technology is part of SIG Plc, one of Europe’s leading suppliers of construction products and provides a complete and impartial design and supply service, with access to an unrivalled choice of roofing products. There would be few other teams able to take on such a project.

Roof Design

Whilst taking on the design liability for the roof, SIG Design and Technology would need to meet the original design intent of the architects and the planning constraints. A new steel frame would infill between all the existing buildings and incorporate significant movement in places of up to 20mm horizontally and vertically. To meet these requirements, the team would have to work collaboratively from the start.

D&T’s technical team, supported by SIG Zinc and Copper (SIG Hard Metals) and SIGA Slate, working collaboratively with E J Roberts roofing and working closely alongside Wates Group’s Project Manager, and the cladding and window manufacturers, developed and executed the design, including over 300 new details.

Secret box gutters in zinc above high level dormers on Denman Street

Detail of the secret box butter behind the dormer (shown as a dotted line) and dormer abutment

Combining Three Roofing Technologies

To meet the complex form of the roof, three separate technologies were combined.

• • 1450m² of Cwy-ybughail Welsh Slate for the sloping facets, including some areas at 15 degrees pitch,
  • elZinc Lava Spanish zinc for cladding, dormers, flashings, cappings and rainwater goods including extensive bespoke elements,
  • IKO Permatec Hot Melt for terraces and flat roofing and for the BMU behind the iconic Lights.

The design would need to meet the robustness required for a city centre location with wind speeds of up to 100mph, so the team constructed a test rig at the Vinci Test Technology Centre in Leighton Buzzard and tested it to European standards of weather-tightness with simulated wind and driving rain. The rig went through several iterations to ensure the robustness of the details which included measures to ensure all elements would be secure.

The scheme combines facades of slate, dark grey zinc and hot melt (Photo: E J Roberts Roofing)

Construction and Completion

Construction took place above and around three flagship retail units and behind the Piccadilly Lights, all of which would continue to operate, in one of the busiest parts of the city.

All materials were supplied through SIG’s extensive supply chain, largely via their SIG Roofing branch at Kentish Town, to a separate holding area near the site to supply on an as-needed basis. All materials were craned onto site, but the crane had to be dismantled before the roof was completed and the team found a way to store 28,000 slates on the roof as it was being installed.

Whilst the architectural and structural details were modelled in BIM, the involvement of several rebuilt historic facades often meant that details had to be reworked on site.

Design and construction of the fabulous roof at Lucent W1 has taken over four years to complete. Construction alone required monthly and sometimes weekly visits, dozens of operatives, and hundreds of meetings online and in person.

Now that the project is completed, the huge collaborative team that made it happen can look back on an architectural masterpiece executed with unprecedented levels of commitment with pride at a job well done.

Some of the multidisciplinary crew from E J Roberts Roofing who installed the complex roof at Lucent W1(Photo: E J Roberts Roofing).

>>Read more coverage of the Lucent W1 roof project