illbruck hybrid sealant chosen for UK-first precast residential towers

London City Island is a residential development comprising 10 buildings of up to 27 storeys in height and containing over 1,700 apartments.

illbruck’s SP525 hybrid sealant is playing a vital role in the construction of an innovative new residential development in East London.

London City Island is a residential development comprising 10 buildings of up to 27 storeys in height and containing over 1,700 apartments. The developer is Ballymore Group.

Located on a peninsular of land where the River Lea meets the Thames, these colourful and individually-designed structures each comprise a pre-cast concrete frame comprising internal 200mm-thick pre-cast walls supporting 200mm-thick pre-stressed concrete planks.

However, it is the external brick sandwich panels which form the most striking feature. The panels, manufactured by Dutch company Hurks, are a new form of pre-cast construction not seen before in the residential market in the UK.

They comprise an internal element of 250mm thick grey loadbearing concrete with insulation and a full width cavity, finished externally with 100mm wide brickwork clad in striking coloured brickwork in black, red, blue and white for the buildings in Phase1. The prefabricated wall units allow exceptionally rapid construction and are lifted into place by crane with all windows & glazing and balcony brackets pre-installed, with bolt-on balconies to follow.

Richard explains,

“Our SP525 was specified via illbruck Benelux to Hurks; illbruck UK supported it and also included the manufacture of a non-standard colour”.

Erection of Phase 1 including the cream coloured Building G was started in October 2014 and completed ahead of schedule a year later. Phase 2, comprising of the next six blocks commenced in May 2016.

illbruck’s SP525 hybrid sealant plays a vital role in making the joints between the panels airtight. After the panels were positioned, sub-contractor Precast Concrete Structures (as a specialised sub-contractor for the installation of the Hurks system) applied a reinforcement grout before applying SP525 to a primed surface into nominal 20mm gaps to provide an internal air seal.

illbruck was approached to manufacture SP525 in a non-standard colour.

illbruck’s Regional Manager, Richard Bacon says

“One of the biggest challenges for us was to provide SP525 as a weatherseal in a non-standard colour to match the cream colour of Building G. Our standard colours were not a sufficiently suitable match.” The colour chosen by Ballymore’s Design Team was RAL1016 Oyster White and was manufactured and delivered on schedule from our production facility in Treunreut, Bavaria. illbruck now offer RAL1016 Oyster White as a standard colour.”

Besides the product’s performance specification, SP525 was chosen for its usability and low health impact.

Richard says,

“SP525 is an inert sealant that is VOC-free, isocyanate-free, silicone-free and solvent-free. So it is an ideal sealant in an internal residential application”.

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