Repairs to an iconic London landmark
Built in 1972 by the noted architect Richard Seifert, the Hilton London Metropole is one of the tallest buildings in Westminster. Richard Seifert was also responsible for Centre Point and Tower 42 (formally the NatWest Tower).
The Northeast and Southwest elevations of the Tower Wing part of the hotel are clad in large format, shaped, concrete panels fixed to the main structure. The concrete panels were rendered and had an external finish of tesserae (textured mosaic tiles). Some years ago, in was noted that pieces of concrete (mainly on the corners) on the Northeast elevation had started to delaminate. A protective fan was erected over the busy pavement on Edgeware Road as a precaution.
In 2021 CRL Surveys were engaged to carry out a programme of testing and investigation works to the Tower Wing and East Wing of the building to assess the type and nature of the defects. A detailed report was produced and Concrete Repairs Limited (CRL) were approached by the Contract Administrator to put together a specification for pricing and assist with the assessment of quantities and scope. After a long and involved tender/negotiation process, and a lot of informal ECI, CRL were awarded the project in April 2022.
The Temporary Works required to access the building were significant and necessitated bringing in our sister company, Samuely Consulting Engineers, as checking engineers for the ground conditions and scaffold. A heavy-duty gantry was erected to bridge the pavement and subway entrances and a 36-lift boarded scaffold with stair tower was erected above. The tallest scaffold ever erected by CRL! Licencing was also complex as the scaffold is on a TfL Red Route. The scaffolding was supplied and installed by Tone Scaffolding Services.
Whilst the scaffolding was being erected, a bespoke repair specification was produced by CRL’s Site Manager in conjunction with Fosroc to ensure that the finished repairs met the performance specification and matched the surrounding tesserae. An excellent texture-matched finish was achieved, and the final product is testament to the skill of the site team!
During the course of the repair works it was noted that besides the areas that required traditional concrete repairs, there were additional hollow-sounding areas of render. Engineers from ARUP Consulting Engineers were commissioned to provide advice on the render retention.
Helifix (manufacturers of helical wall ties, fixings & masonry repair systems) were called in to conduct pull off tests to the concrete structure and render. Once the results were evaluated CRL, as a Helifix approved installer, were instructed to install circa 9000, 8mm diameter, 170mm long Stainless steel Cemen-Ties building in a 400mmx 400mm pattern across the entire East Wing façade.
To mask the visual impact of the holes, CRL were instructed to coat the entire East Wing façade of the Tower Wing with Keim Soldalit. The existing surface was steam-cleaned using the Doff cleaning system.