High-performance roofing membranes help bring landmark building back to its best
In its challenging city-centre location, Guy’s Tower has undergone a huge refurbishment, with the ageing 143-metre building upgraded to current performance, environmental and aesthetic standards.
Overcoming a series of unique on-site challenges – including working at height in a live hospital environment – Radmat Building Products approved contractor, Richardson Roofing, installed more than 1,000sq m of high-performance roofing membranes to help bring the landmark building back to its best.
Originally founded in 1721, the hospital built the 34-storey Guy's Tower in 1974. When a feasibility study commissioned by Guy’s and St Thomas’ NHS Foundation Trust in 2008 revealed severe deterioration of its concrete facade, failing windows and poor environmental performance, a comprehensive refurbishment was deemed the safest and most cost-effective solution.
Designed by architects Penoyre and Prasad and delivered by Balfour Beatty, the £26m refurbishment included the application of new cladding and glazing systems, and thermal upgrade and waterproofing of a 45° pitched roof and a series of inverted terraces. Balfour Beatty also required an innovative environmentally-friendly solution that would deliver the thermal performance required while ensuring health and safety of operatives and members of the public were covered.
With safety absolutely paramount across the development, Radmat’s Esha range of membranes proved the perfect solution, minimising material cost, application time and waste disposals. The use of Esha systems also enabled Radmat approved contractor, Richardson Roofing, to meet Balfour Beatty’s highest safety standards in line with its Zero Harm Vision.
For the asphalt-covered sloping roof on the 34th floor, EshaUniversal waterproofing was specified with ProTherm PIR (polyisocyanurate) insulation as part of a complete Radmat roofing system. Made from recycled materials and 100% recyclable, EshaUniversal offered a simple application and the required performance to meet the demands of this complex and sustainable refurbishment.
Offering an efficient and safe installation, a 2mm-thick EshaBase SA Alu self-adhesive vapour control layer was adhered directly to the existing asphalt using Esha SA Primer. Due to the wind loading 142m above London, the 120mm-thick ProTherm PIR insulation was mechanically fixed to the deck using Radmat ProFast fixings, prior to the mechanical fastening of the EshaUniversal single-layer membrane. The resulting roof achieved current Approved Document L requirements for thermal performance. Low-level flat roof areas were also covered with the same specification to provide an assurance of trouble-free performance for many years to come.
On the inverted roofs on levels 34 and 31, asbestos tiles were safely removed and the asphalt was overlaid with two layers of Radmat’s EshaGum 3mm reinforced bitumen membrane. The existing asphalt surface was prepared to ensure no defects or blisters across the entire application prior to the installation of the EshaGum, with a 200mm-thick Radmat ProTherm inverted roof insulation board installed to upgrade the roof’s thermal performance. Completing the installation was the application of paving slabs on spacers resulting in a series of terraces that now meet the thermal performance requirements of Part L of the Building Regulations.
Despite the complex refurbishment presenting a number of challenges on-site, innovative roofing solutions have helped to keep the landmark refurbishment on course for its 2014 completion.