Structural Renovations have recently been completing waterproofing works in various locations within the Shell Centre in Central London.
Our works have involved controlling water ingress within the basement and lift pit areas of the main tower.
The 27 storey tower and 3 (now demolished) 9 storey wings were constructed between 1957 and 1962, on part the site used for the Festival of Britain. At the time the tower was the tallest building in the UK and the largest office building, by floor space, in Europe.
Our first phase of works involved pouring a new screed, laid to falls, within a double width lift pit using Flexcrete Fastfill repair mortar, modified with kiln dried quartz sand. The screed and 150mm of the adjacent walls were then waterproofed using Flexcrete Cemprotec E942, a cementitious waterproof coating, prior to the lift engineers reinstalling the lift buffers and rails.
The second phase of works to 2No. adjacent lift pits was based upon a bespoke waterproofing solution designed by Parkinson VTC Ltd. The works involved the installation of a wire mesh box around both sumps within the lift pits, prior to the installation of a 400mm thick layer of 10mm aggregate, to act as a soak away. A 450mm thick layer of Flexcrete Fastfill modified with 10mm aggregate was then installed over the soakaway. The screed and 150mm of the adjacent walls were then waterproofed using Flexcrete Cemprotec E942.
The limited space on site and strict delivery periods meant that up to 4 tonnes of material were being mixed and laid by hand each day.
A major redevelopment of the area, involving new office, retail and residential space has transformed the site and 1,700 Shell staff, who were temporarily relocated to Canary Wharf, have moved back to inhabit the main tower.
Structural Renovations were awarded the contract to complete extensive structural repairs and apply protective coatings to all reinforced concrete within the landmark structure, known as The Observer Building, in Hastings town centre.
The building was originally constructed for the publishers and printers, F. J. Parsons, in 1924 and was designed by the Hastings architect, Henry Ward.
The building was subsequently used by The Observer Newspaper as both a printworks and its administrative centre, until vacating in 1985. The building has remained empty and neglected in the years between, which has allowed significant deterioration to be caused to the entire building fabric and in particular the reinforced concrete structure.
A number of surveys have been conducted over the years, when various parties showed an interest in taking on the building and each survey shows the increasing damage caused, in the main, by water ingress.
The building was finally purchased by White Rock Neighbourhood Ventures in late 2018, who, together with the assistance of various funders, intend to bring this impressive building back to life and utilise the enormous space available.
Our works have involved surveying all concrete surfaces to identify the full extent of defective concrete, before its removal back to a sound substrate. All exposed reinforcement is carefully prepared prior to be in treated with a proprietary primer. The prepared areas are reinstated using a cementitious, polymer modified repair mortar.
Due to the sheer size of the structure internally (in excess of 5,000m²), it was decided that the protective anti-carbonation coatings would be applied by airless spray equipment, which was purchased specifically for this project and has enabled the process to be sped up considerably.
During the works approximately 15 tonnes of repair mortar will be used and over 2,000 litres of anti-carbonation coatings.
It is testament to the original design and construction of this building, which was left to decay for so long that its repair was viable, and demolition was not necessary.
The external elevations of the building are hoped to be completed as part of a separate phase, which will be carried out in the near future.
The 4th and 5th floors are currently being refurbished at Devon House and Structural Renovations have been employed to carry out the concrete repairs.
Devon House is situated on Great Portland Street and is part of the Langham Estate portfolio.
The floor slabs have been constructed from clinker concrete and steel filler joists. The filler joists have corroded and caused the concrete and plaster to crack and spall.
The defective concrete was removed from around the filler joists, the corrosion was removed by mechanical wire brushing and then the cleaned steel was primed with two coats of Fosroc Nitoprime Zincrich Plus. A galvanised mesh was fixed over the exposed steel and the concrete was reinstated with Fosroc Renderoc HB.
Structural Renovations have been working at Hallam House on Hallam Street since late 2018. The building is part of the Langham Estate portfolio and we have been working closely with the Estate’s Principal Contractor, Millane Contract Services and the Consulting Engineer, Jacobs.
The building is currently being refurbished and upgraded. In the basement plant rooms and brick vaults we have installed a new waterproof render using Flexcrete materials. Concrete repairs and anti-carbonation coatings have been carried out within the rear lightwell to the window heads and cills.
Internally, the existing lift was removed, and we were required to carry out extensive repairs to the staircase that wraps around the lift core. Existing supporting steel work was cut out and the landings and strings were repaired back to the original surface profile as required by the contractor installing the new glass lift.
Structural Renovations have secured a 12 week project to remove brick slips from a 5 storey purpose built office block in Hove, known as Preece House.
The structure was built in 1980 when the fixing of brick slips (thin sections of brick) was still a relatively popular design feature. This gave the impression of an entirely brick built building, when in fact the slips were adhered, using mortar over the floor plate edges to conceal them, a little like tiling.
Over time the mortar used to affix the slips can fail, either through poor preparation at time of construction, or freeze/thaw activity, if moisture has penetrated behind them. This can lead to failure and the slips falling from the building, causing a significant health and safety risk.
Following a diagnostic survey earlier in the year it was identified that a significant amount of brick slips had failed or were beginning to fail. At this time the building was made safe by removing all loose slips, to reduce the risk to people or property.
A number of remedial actions were considered and in October the decision was taken to remove all brick slips from the building, thus removing the health and safety risk altogether.
The majority of the works is being carried out from scaffolding, which due to the shape of the building is cantilevered in places. Low level areas are being accessed from lightweight aluminium mobile towers.
Following the brick slip removal process, the exposed reinforced concrete substrate is surveyed, to identify if repairs are required. These are being carried out using Flexcrete Monomix, as part of their proprietary concrete repair system.
Once repaired we are contracted to apply Monolevel FC (fairing mortar), followed by the application of Flexcrete Monodex Ultra (pigmented anti-carbonation coating).
Associated works items, such as replacing perished sealants and localised repointing have now also been instructed and it is anticipated that the works will complete in mid-February 2019.
Structural Renovations secured a further phase of concrete repair work at the Barbican Estate in June 2018. The works include the 3No. tower blocks, 11No. terrace blocks and 9No. underground car park areas.
Similar to previous phases that Structural Renovations have completed the works involve repairing defective bush-hammered and fair-faced concrete surfaces, using specialist hand-placed mortars, approved by our client, the Corporation of London and English Heritage.
In additional we are contracted to complete resin-injection to seal ongoing leaks from podium areas, together with the installation anodic protection, to control corrosion within the buried steel reinforcement.
The works are being accessed by various means, including abseiling for the towers and terraces, scaffold for isolated structures and lightweight aluminium mobile tower within the car parks.
The entire estate is Grade II listed due to it being one of London’s principal examples of Brutalist Architecture but meaning any necessary repairs are to be carried our sensitively, so as not to detract from the original design ethos of the architects, Chamberlain, Powell & Bon.
The project is due for completion in May 2019.