Waterproofing of the double-storey basement within a 125m high, 28 storey, elegant glass and steel skyscraper designed by Foster & Partners. Situated opposite the world famous Lloyds of London building in the heart of the City of London, the site has 320,000 ft2 of lettable space, plus vast basement area.
To ensure the 50,000 ft2 basement spread over 2 floors, withstands hydrostatic pressure and remains water-tight.
Xypex Admix was used to waterproof the basement slab against water ingress. Additionally the lift pits for the 21 elevators were cast with Xypex Admix C1000NF.
To aid the value engineering of this project, the deep basement slab was poured as a “split slab”. This monolithic process allows cost to be managed without compromising waterproofing performance. The 2 sections (Xypex and non Xypex concrete) were poured at the same time, ensuring that no cold joint was produced. The Xypex Admix depth was managed on site by our Site Service team.
Xypex Admix C Series – Basement slab
Hydroswell Bentostrip – Day joints and sealing against piles
Value engineering was achieved through the split slab pour method, but also as a result of achieving extremely large pours sizes in-line with the contractors’ requirements. Xypex does not limit pour sizes or aspect ratios, as long as the design criteria limiting crack widths to 0.3mm are adhered to.
DOWNLOADSCASE STUDY - THE WILLIS BUILDING, LONDON
BASEMENTS & SUB-STRUCTURES