Project: Liberty, London
Main Contractor: DBR Ltd.
Project Description: JDC Scaffolding were asked by DBR Ltd to price a large scaffolding package, in 2Q 2019, to enable the external and internal refurbishment of the iconic Liberty Store. A Tudor revival building constructed in 1924, built from the timbers of two ships: HMS Impregnable (formerly HMS Howe) and HMS Hindustan. The frontage of the building on Great Marlborough Street is the same length as HMS Hindustan. Liberty, London is a Grade II* listed building.
Further to DBR securing the project we were approached with a view to carrying out the works as DBR had been impressed with our initial bid. We were pleased to secure the contract 1Q 2020 as we have not worked with DBR before, and with Liberty who are a very specific client. Following final financial negotiations works commenced in 1Q 2020.
The works are design intensive due to the historic fabric of the internal and external of the building and have been split into separate phases.
The scaffold design was carried, In House, out by JDC Scaffolding with supporting calculations originally by 48.3 and later by RDG Engineering. DBR Ltd acting as Temporary Works co-ordinator.
The designed scaffolding works comprise generally of the following:-
- Bespoke gantry to rear elevation to support three levels of cabins inclusive of adjacent high level lifting arrangement
- Access scaffolding to rear elevation inclusive of beaming over existing shopfront.
- Access scaffolding to Carnaby Street, Kingly Street & Grapes Elevations
- Bridged access to Kingly Street Clock Bridge.
- Gantry and full access scaffolding to main front façade inclusive of bespoke propping arrangement in basement.
- Banner frame and printed banner (From photographic survey) to all elevations.
- Internal atria & temporary roofs.
SCAFFOLD BRIEF
Design – General
The works are design intensive due to the historic fabric of the internal and external of the building and have been split into separate phases.
The scaffold design was carried, In House, out by JDC Scaffolding with supporting calculations originally by 48.3 and later by RDG Engineering. DBR Ltd acting as Temporary Works co-ordinator.
The designed scaffolding works comprise generally of the following:-
- Bespoke gantry to rear elevation to support three levels of cabins inclusive of adjacent high level lifting arrangement
- Access scaffolding to rear elevation inclusive of beaming over existing shopfront.
- Access scaffolding to Carnaby Street, Kingly Street & Grapes Elevations
- Bridged access to Kingly Street Clock Bridge.
- Gantry and full access scaffolding to main front façade inclusive of bespoke propping arrangement in basement.
- Banner frame and printed banner (From photographic survey) to all elevations.
- Internal atria & temporary roofs.
Rear Gantry
DBR requested a requirement for a gantry to be constructed at the rear of the store to site their welfare set up. Little Marlborough Street at the rear is a very narrow street with limited vehicular access. DBR procured a number of demountable cabins that were erected by hand on site that we had to incorporate into our design and allow for four separate gantry levels, maintaining clear span, Haki stair access and safe access for Liberty personnel to enter the store.
Access Scaffolding
The three rear elevations of the building had traditional access scaffolding designed, however, the tie detail had to be carefully considered and designed to allow a sympathetic tie pattern to the historic timber facades and also to take into account the limited pull test reactions discovered in the original masonry. This led to a bespoke tie arrangement being designed in localised areas.
Kingly Street Clock Bridge
Along the Kingly Street elevation are two bridges which span between the Liberty store and the adjacent building. Only one bridge was required to be scaffolded. The access scaffold was always planned to be bridged over the road with the internal support picked up from the main access scaffolding.
The other end was planned to be supported from heavy duty towers founded at ground floor level. This method changed and the support was finally designed to mechanically fix to the wall of the adjacent building which highlighted a requirement for Shear Tie testing which we carried out.
Great Marlborough Street Elevation
The design to the main front façade of the building had to be carefully considered. The gantry had to be designed with supporting towers in specific positions to allow load transfer through the backpropping. These towers were joined with modular X-Beams. Pedestrian access had to be allowed along the footpath, over the incorporated pedestrian crossing and into the store itself. The internal gantry supports had to be designed to be a sufficient distance from the front of the store to allow specialist craftsmen access to the historic façade at ground level.
The main access scaffold had to be designed to give safe access to craftsmen inclusive of beamed inset scaffolds which could not impose any load from the scaffold onto the structure. The scaffold also had to incorporate a Haki staircase and had to support high level beamed platforms to give safe working access to the chimneys, a Gilded Boat feature and other roof detailing.
Banner Frame
The access scaffolding also had to be designed to incorporate the imposed reactions of an offset tubular banner frame and a complete vinyl banner wrap to the elevations. The banner frame would be fixed to the scaffold and all projecting features. All joints, connections and angles formed in Kee Klamp.
Internal Atria
Internally to the store are three full height open atria. All three have a requirement for repairs and refurbishment at high level. This was achieved by designing spanning beamed & boarded platforms over the atria whilst adhering to the strict loading criteria for the existing floors.
The central atrium also has an additional requirement which has led to a design for a complete perimeter suspended scaffold to give access for repairs and refurbishment to an existing decorative frieze.
Each atrium has a timber and glazed roof light which has a designed temporary roof covering which again meets specific loading criteria.
SKILLS AND EXPERTISE
The store is very high profile and the ultimate client has an office on site. The client is very hands on and has a view of all areas of site at all times. It has been vitally important that we have found practical and workable solutions to all problems, we are working safely at all times and that our finished product is aesthetically pleasing. We have had extremely positive feedback on all counts to date.
Prior to commencement on site, and since, our In-House Design Department have worked alongside DBR to find practical and workable solutions to all challenges we have met thus far. In a number of areas, we have suggested differing solutions, sometimes not the obvious answer, and the final designs have ensured satisfaction for all parties involved in the design and these solutions have been communicated to our Contracts Department and operatives on site to ensure that risks are reduced.
We pride ourselves at all times on our attention to detail in both our design drawings and final delivery on site. The phased completion of our external scaffolds, complete with banner wraps, on this project is testament to both these attributes.
CHALLENGES
Materials Access
There is no tower crane on site and ground level material routes on the scheme are limited and congested. Kingly Street on one side is narrow, one way, has a limited opening time and has a barrier which closes off access early in the day. Little Marlborough Street to the rear has the DBR gantry and welfare set up and is also the main access for Liberty staff. Carnaby Street to the other side is paved and has limited vehicular access. Both Kingly and Carnaby Street are in the heart of London’s West End and, during normal times, are extremely busy with pedestrians. Material deliveries therefore have had to be carefully planned and booked and strictly carried out to our SSOW.
During contract negotiations it was agreed that all materials for the internal atria scaffolds at third floor would be delivered and distributed during night shifts. Long materials would be raised via the rear hoist and carried through the building to the work face, short materials could be raised using a service lift. We would have limited storage space as the store was still live, we could not store quantities of materials on the floor because of aesthetics and loading restrictions. During all materials handling operations many of the store items, china and the like, remained in place.
The Covid lockdown assisted during the erection process as the store was closed and we could deliver during the day, we were also allowed to erect a tower to assist with lifting to high level. The store has now reopened to the public and the striking of these elements is being carried out as originally planned.
Covid-19
The rear gantry and works to Kingly and Carnaby Street were carried out 1Q 2020, a great deal of the remaining on-site works were carried out during the height of the Covid 19 Pandemic. Our operatives and management have worked to the strict site rules and updated policies implemented by DBR with regards to Social Distancing, breaks, welfare use, face coverings, testing etc. Liberty’s own strict security arrangements, as well as adhering to the JDC Scaffolding SSOW and Covid 19 rules.
Banner Wrap
The scaffold as a whole was covered in a vinyl banner with replicating the existing façade. We contacted our long-term supplier, Concorde Graphic, to price the works and get involved early in the project.
A full external survey of the exterior of the building had been carried out by others Concordes art department worked in collaboration with the photographer, stitching together the images, to produce a number of sample panels which have been attached to the scaffold for approval by both DBR management and representatives of the ultimate client – Liberty, London. Colours of timber, render and windows were altered and amended until the client accepted the proposed banner and whole facades could be produced – The largest of which was 75.00m x 16.00m in five sections, with each join completely hidden and the client was extremely pleased with the final aesthetic result.
JDC Scaffolding installed a banner frame to all element to accept the banner. The offset frame has Kee Klamp elements at all joint and junctions to ensure an aesthetically pleasing finish and to minimise any potential damage which could be caused by standard scaffold fittings.
Great Marlborough Street Facade
An independent scaffold was required to give access for various trades refurbishing the existing façade. The Tudor revival façade is made up of hardwood timber with lightweight masonry infills and a render finish.
A 72.00m long gantry was required to support the scaffold above. Challenges we had to overcome for the gantry were:-
- Narrow pavement width
- Pavement lights & smoke vents
- Specific location to transfer loads to basement
- A pedestrian crossing and zig zags for half the façade
- A loading area for a large part of the remaining façade
Along the length of the façade there is a number of inset features which, we later discovered, had little or no capacity to carry any loads. A cantilever solution was designed, spurred up from the pedestrian gantry, complete with 10 No. check fittings at each connection.
Other items which had to be incorporated into the main façade design were:-
- Inset lightweight timber balconies
- Projecting timber bay windows
- Full length historic, decorative timber frieze at gantry beam level
- Main store entrance
- Haki staircase
- High level beamed access to Gilded Boat feature
Roof Works
The roof at Liberty has been altered over the past 100 years and is now a mish mash of old and new structures, 3 No. historic timber rooflights, decorative chimneys, a Gilded Boat feature and a variety of roof structures, plant rooms and the like.
The main roof has a very limited load capacity and there has been a large amount of scaffold required – temporary roofs over the rooflights, access to the chimneys, edge protection, access scaffold to high level walls. Our management teams has updated our Designs, RAMS & SSOW to ensure that all scaffolds have been fit for purpose.
Budget
Budget has been a driving factor of this project, even more so since the Covid lockdown. Liberty obviously relies on footfall and retail sales which were nil whilst the shop was closed. We have worked very closely with DBR and the client to ensure adherence to the original budget and value engineering of any variations to give best value.
Safety of Public
Due to the location of the Liberty project, in the heart of the West End, pedestrian traffic has been high, except during the height of Covid. We have ensured best practice whilst erecting and striking scaffolds inclusive of tethered tools, Combisafe Fans, exclusion zones and the like.
Designs
Testimonial
JDC Designers and Management Team have interfaced well with the DBR and Clients Design Team throughout the project to develop a scaffold that delivers access to all the areas we required to carry out the required restoration and conservation works. JDC managed to develop a design that met DBR needs and minimised the need to carry out adaptions throughout the construction phase.” Giles Bilbrough, DBR Ltd.
Images by Gary Britton