Case Study: St Helens Hospital Redevelopment

The £338m project involved the construction of a new Diagnostic Treatment Centre extending the hospital site over challenging ground conditions

A gas risk assessment concluded that levels of both carbon dioxide and methane gasses were elevated on the site and that appropriate gas protection measures were required

The substructure required a passive gas venting system, allowing any gas emissions to be dispersed away from under the building

Fosroc’s role in the project was to provide the gas protection membrane for the suspended ground bearing slab, for which Fosroc Proofex Engage was specified

Fosroc worked closely with Project Manager, Taylor Woodrow Construction, Consultants Arup and Architects Capita to develop appropriate solutions from an early stage

Fosroc’s CAD Centre produced standard and bespoke details

Over 10,000m² of Fosroc Proofex Engage waterproof and gas-resistant membrane was pre-applied to the ground slab and lift pits. Fosroc Proofex Engage created an ideal permanent layer of protection over the quarry areas where ground settlement may continue

Pile heads in a contiguous pile wall were applied with Fosroc Proofex WG, a high performance epoxy resin grout that mechanically bonds with Fosroc Proofex Engage to form a robust waterproof seal. Fosroc Nitocote EP405 was used to continue the membrane through retaining walls and columns at pile caps and lap with the Fosroc Proofex Engage

Fosroc Proofex LM liquid membrane was used for complex detailing work such as corner details and service entries

In addition, more than 1600m² of Fosroc Proofex 3000MR methane resistant self-adhesive membrane was post-applied to the vertical faces and used for detailing work around the perimeter of the building

To give further protection, Fosroc Proofex Total loose-laid gas impervious membrane was applied across the masonry wall cavity at the perimeter toe details

Fosroc’s products provided an integrated waterproofing and gas protection solution

Design Manager, Clive Philips of Taylor Woodrow Construction said: “Fosroc UK’s design services and support have been really helpful”

Fosroc UK’s contribution throughout and particularly during the design development phase of the project was crucial and much appreciated