July 16, 2020
Cantillon were appointed by Soho Estates to undertake the demolition and enabling works contract on the prestigious Ilona Rose House scheme, situated on Charing Cross Road bounding the Soho district in the City of Westminster.
The site comprised several mixed-use buildings including the former Foyles Book store, which was bounded by numerous party and boundary wall conditions, with adjoining businesses, restaurants and notably the Grade 1 listed House of St Barnabas and its 18th Century Chapel located directly opposite the site.
The project commenced on site in March 2017, following a three-month pre-demolition services period whereby Cantillon took a lead role in coordinating and gaining public support, during a consultation to negotiate the closure of Manette Street, bounding the north of the site with the WCC Highways team. This would prove crucial in providing the logistics area to facilitate the heavy plant and traffic access and egress during the works.
Detailed noise prediction models were undertaken in advance of the demolition activities, identifying areas of potential noise emissions, which would be used to agree the s61 Prior Consent with WCC.
Following various noise trials and consultation meetings with the local community and stakeholders Cantillon developed a neighbourly strategy to manage very sensitive stakeholders.
The outline scope included the demolition and clearance of all existing buildings site wide, down to and including the lowest slabs and foundations. The demolition also included the design and installation of a façade retention
system prior to the demolition of the 12-13 Greek Street building behind the retained façade. During the demolition, Cantillon carried out the installation of temporary works support to highways, pile probing and piling platform installation required prior to undertaking the enabling works in preparation for the ground source heating system works and subsequent piling phases both carried out by Cantillon.
Cantillon also managed and attended upon a significant historic excavation carried out by Museum of London Archaeological team, which required a sequenced approach and coordination with the wider works.
Three separate Approval in Principles were required to be agreed with Westminster City Council for the Façade retention support system to 12-13 Greek Street, perimeter WCC Highways and the deep basement excavation, itself with a formation at 17m below ground level. All design and development was carried out in house by the Cantillon engineering team.
The Ground source heating works, required the installation of two separate systems under Cantillon’s package of works. The first involved the installation of two abstraction and two re-injection wells, with an open loop borehole well system, which reached 185m into the chalk aquifer.
The second system involved the installation of closed loops combined with the installation of the bearing piles to create 85nr thermal piles. Upon completion both systems would be tested in preparation to be incorporated into the future building.
The piling package also carried out under Cantillon’s scope, required the installation of a 900mm diameter secant wall to be installed to the full site perimeter, 105nr bearing piles up to 50m deep as well as a series of mini piles to provide the foundation for the proposed 12-13 Greek Street building. The piling works were carried out in close proximity to and were restricted over the adjacent northern line tunnel situated beneath Charing Cross Road.
Cantillon shall complete the 40,000 m3 bulk excavation down to final formation level 17m below the adjacent ground level highways and shall install the permanent works RC capping beams as necessary prior to the installation of substantial deep basement temporary works propping, in the region of 850 tonnes.
Overall, the project duration is planned to extend to complete in March 2019, incorporating further basement construction in addition to each of the aforementioned numerous packages and technical challenges, maximising the overlap potential between each phase and providing a seamless project delivered with our partners for our Client Soho Estates.