The Triplets, Kings Cross

Remains of a Bygone Era

There are only a handful of gasholders remaining around the UK, most of these hulking structures have been demolished to make way for new developments. They may not be everybody’s idea of beauty, but gasholders are a rapidly disappearing reminder of our country’s proud Victorian heritage, so it’s rather refreshing to see that the cast iron frames surrounding four of London’s King’s Cross gas holders are being saved and re-used in a huge, new, mixed-use Argent development.

Originally constructed in 1860-67, gasholders 8, 10, 11 and 12 have been been dismantled and restored by a specialist engineering firm in Yorkshire. When resurrected, gasholder number 8 will contain a small park and event space, while numbers 10,11 and 12, a trio of gasometers conjoined by a central spine and known as the ‘Siamese Triplets’, will be home to drum-shaped apartment blocks.

Initially built for storage of town gas for Pancras Gasworks, the largest gasworks in London, the Triplets are Grade II listed. Their wrought iron and riveted lattice girders have been dismantled and will be painstakingly repaired before being reassembled around a series of apartment buildings on the King’s Cross site, which is the largest urban redevelopment scheme in Europe.

They will sit further north than their original footprint, just north of Regent’s Canal; a stunning setting that will provide the Triplets’ residents with views of the water and nearby nature reserve. Being so close to the canal and railway lines, it gives a touching nod to the original setting of the Triplets and was approved by English Heritage as the most appropriate spot for these colossal industrial symbols.

A New Lease of Life

Wilkinson Eyre Architects were tasked with providing the design to transform these 1860s structures into new flats complete with roof gardens, and they have done a magnificent job of making the most of these elaborate cast iron frames. Incorporating the Triplets into a brand new development was no mean feat, with three tiers of hollow cylindrical cast iron columns, cast iron capitals and three tiers of wrought iron riveted lattice girders to take into account. The architects’ concept proposed three circular buildings of differing heights to mirror the movement of the original gasholders, which would have risen up or down depending on the pressure of the gas within.

The Triplets will house high-value market residential units as well as retail units on the ground floor and a restaurant on the top floor. When complete in 2017, the Triplets will be the world’s only connected triplet to be refurbished into residential spaces.

PUDLO has been involved with this project from the design phase and, since the basement construction phase commenced in March 2015, continue to be present onsite. The PUDLO onsite guidance has proved valuable along the way for waterproofing podium deck, basement car park and lift pits which are all being poured using PUDLO concrete. With Henry Construction heading up the below-ground PUDLO work, and A.J. Morrisroe taking the reins for the PUDLO podium deck above ground level, a seamless meeting of minds has been essential during this project. PUDLO has been working closely with both of these contractors to ensure the concrete is placed correctly and their shared wall joint remains waterproof.

Bespoke details were drawn up by PUDLO’s in-house technical team to eliminate any concerns when taking on such a mammoth project. This in-house service goes hand in hand with the implementation of the TechICT and ISO 9001 accredited PUDLO onsite support system. This site support team ensures that the iconic King’s Cross development will be fully waterproofed and adopted under the unmatched PUDLO 20 year warranty.

Contractor: Argent LLP

Groundworkers: A.J. Morrisroe & Sons Ltd and Henry Construction Projects Ltd

Architect: Wilkinson Eyre Architects