Structural Renovations have been awarded the contract by The City of London Corporation to verify the condition of the concrete on 10 residential blocks of flats in the Southwark, Southeast London.
The ages of the various blocks range between 65 and 90 years and are therefore some of the oldest flats in the area.
Although all the blocks appear to be predominantly constructed from brick, they do in fact contain significant quantities of reinforced concrete, in the form of public and private balcony supporting slabs, window surrounds, roof overhangs and lintels.
Our brief is to establish whether cast-in chlorides, combined with carbonation attack over time, has affected the condition of the buried reinforcement leading to cracking or spalling concrete which has the potential to compromise structural integrity.
The works will be carried out over an 8 week period, using specialist technicians working from mobile elevated works platforms, roped access techniques (abseil) and mobile towers.
Following completion of the site activities, a structural engineer’s assessment will determine the extent of necessary concrete repair and corrosion control. We will then develop and suitable specification, based upon one of the recognised concrete repair manufacturers repair systems.
This survey project will be completed whilst the blocks are live and therefore it is a requirement for us to ensure these works are completed in an efficient and timely manner, causing minimal disruption to residents.
Structural Renovations Limited are currently restoring part of the river wall in Wapping. The location of our works is at Pelican Wharf, which although was a wharf and warehouse well into the 20th century, is now a luxury apartment block built in 1987.
Access to the works area is limited by the tides which has meant careful planning and programming has had to be put into place to maximise the available working times. We have erected scaffold on the river bed/foreshore, securely fixed to the embankment wall to avoid being washed away at full tide.
The works are concerned with brickwork repair and stabilisation, concrete repair and consolidation and associated ironmongery repairs to the river wall and adjoining access steps between Pelican Wahrf and the historic Prospect of Whitby public house.
Structural Renovations Limited commenced work on site at Westminster Court in September. The project consists of concrete repair, corrosion management and protective coatings to the 9 storey, purpose built residential block, which over looks the sea.
The reinforced concrete had been previously repaired and existing repairs had began to fail, combined with ‘new’ defects that had presented themselves.
The blocks close proximity to the sea has accelerated the deterioration of the concrete due to the effects of airborne chloride contamination and it was therefore proposed that a form of corrosion control should be adopted to prolong the life of not only the repaired areas but the concrete in its entirety.
The working areas have been scaffolded and clad with debris netting, to provide a safe and efficient mean of access.
Following a visual and hammer tap survey, all defective areas of concrete were broken back to sound substrate and the reinforcement treated with a cement rich primer. All prepared and treated areas were then reinstated using a hand placed, polymer modified repair mortar.
The corrosion management system involved drilling and installing vapour phase inhibitor capsules in a grid pattern across all concrete faces. These capsules will release their inhibiting properties over 12-48 months around the reinforcement, providing a passivating protective layer, which reduces exposure to harmful chlorides.
All concrete surfaces are then to be pressure washed to remove dirt and loose materials, followed by the application of a water based primer/adhesion promoter.
Finally, the entire primed area will be protected with a pigmented, elastomeric, anti-carbonation coating.
All products are produced by Sika Limited and this particular system, once complete will provide the client with a 10 year guarantee.
The works are programmed for completion in early November.
Structural Renovations are currently working at Victoria House in London, SW1. Victoria House is a 5 storey residential block completed in 1959. The front elevation is mainly brickwork, whereas the rear elevation extends with concrete access walkways, staircase and access to the basement.
Structural Renovations are employed to carry out extensive concrete repairs to the window cills & heads, walkway soffits, return walls and supporting columns. The defective areas were repaired using Sika MonoTop 615 and then all previously coated areas were treated with SikaGard 675W ElastoColor and all previously uncoated concrete was treated with SikaGard 680S Clearglaze.
The walkway decks, stairs and landings were repaired using Sika MonoTop 630 and were then treated with a reinforced waterproof non-slip coating made up of Sika Bonding Primer, Sikafloor 405, reinforced with Reemat Premium and Sikafloor 420.
Additional works to the front elevation were carried out which included sympathetic colour matched repairs to the front entrance using Remmers Restoration Mortar, replacement render to the gable wall & retaining walls as well as Helifix crack stitching and installation of Helibeams.
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.