The Lighthouse
The Grade II Listed Lighthouse stands prominently on an island site adjacent to the front of King’s Cross Station, formed by the convergence of a number of major routes: Euston Road, Pentonville Road, and Gray’s Inn Road. The area forms a part of the ‘Gateway’ to Central London that is used by millions of workers, residents and international visitors.
Set in the King’s Cross Conservation Area, the original building was a Flat Iron shaped block of shops with an uncertain mix of uses on the upper floors. It was built in 1875 to replace buildings demolished in the construction of the railways. The building sits directly over the Metropolitan and Network rail tunnels supported by large steel girders that span the apex of the tunnels and align with the sub-division of plots on the ground. The building included a lighthouse on the apex, which was reportedly lit every time oysters were available in the store below.
The Lighthouse had remained derelict since the 1990s and was on English Heritage’s Buildings at Risk register. Although subject to earlier planning applications for previous owners, the development had always faltered due to the complex technical issues involved with the redevelopment. The building fabric was in extremely poor condition and rapidly deteriorating prior to the works commencing.
In 2009, Latitude obtained full planning and listed building consent for the complete redevelopment of the Lighthouse behind the retained façades, with construction commencing in 2014. All internal fabric and roof structure was removed down to ground floor level, together with the existing façade of
No 370 Gray’s Inn Road.
The weight of the new building had to match the weight of the existing with all new construction being isolated from the existing to reduce vibration and noise from the trains below.
The new steel structure was inserted into the load bearing cross walls, bay by bay, to maintain even
weight distribution.
The existing façades together with the lighthouse structure were carefully restored.
A new section of façade to match the existing main building was constructed on the site of No 370 Gray’s Inn Road using Gaunt bricks recycled from the demolished chimneys. New floors, lift and stair cores were constructed behind the refurbished façades.
At roof level a new floor of office accommodation was constructed. The office is set back from
the lighthouse structure. Roof top plant, required to service the building, is located in a new mezzanine level set towards the Eastern end of the building, away from the lighthouse.
The massing strategy for the additional roof top accommodation was that it should reduce in scale towards the lighthouse, ensuring the lighthouse remains the prominent feature on the building. The new roof structure also reflects the divisions of the old party walls, so that the rhythm that is established at ground level by the existing pilasters is maintained above the parapet.
The tiles found on the original lighthouse informed the new zinc diamond tile cladding of the roof and the stepped structure reflects the divisions of the old party walls still visible at ground level, while allowing daylight into the new space.
The roof spans an irregular trapezoidal footprint rising up in 3 steps as it moves away from the Lighthouse structure, before descending between the brick ‘chimneys’ at the rear of the building.
Missing a discernible central axis the curvature of the roof varies throughout. The resulting geometry is a combination of eight distinct two-centred arches (3 on each side and 2 for the hips) and a half arch to the rear.
In addition the arched dormers within the roof curve in 2 planes.
Resolving these issues required going back to first principles of geometry to deliver the precise drawings packages required by the Steel, Carpentry and Roofing sub contractors.
