A PFI Extra Care complex near Stoke-on-Trent, is another project benefitting from the use of innovative off-site manufacturing. It combines Isokorb structural thermal break units from Schöck with the Hollowcore system. Holdcroft Fields at Abbey Hulton, provides 175 self-contained one and two bedroomed apartments, with extensive communal facilities, for people over 55. Designed to meet BREEAM Excellent standards, there are two linked three-storey blocks and many of the apartments feature spacious balconies; so the prevention of thermal bridging is a critical consideration.
Quite apart from heat loss, condensation can lead to structural integrity problems and may even encourage mould growth, which has serious medical implications. One of the most effective countermeasures on the market is the Schöck Isokorb structural thermal break. It dramatically reduces thermal energy loss in connective areas and enables inner surface area temperatures to remain well in excess of those likely to cause condensation.
It is the Isokorb type KS14, for concrete-to-steel connectivity, that is being installed in conjunction with the Hollowcore floor system. The precasters breaking out selected cores and cast reinforcement bars in their works. The thermal breaks are then fixed to a template, which match the broken out Hollowcore, complete modules are supplied to site, dropped into position and the broken out Hollowcore filled with insitu concrete.
The Hollowcore has full length voids, with a huge weight saving over floor slabs of equal thickness or strength. So there are efficiencies in transportation and material costs – and with slab sizes typically 1.2m wide by 7.5m long, they are faster to install and provide an immediate working platform for following trades.
The Isokorb type KS14 has verifiable performance values, providing BBA Certification and LABC Registration, as well as comfortably exceeding the requirements of BRE IP1/06 and Part L of the Building Regulations. The temperature factor used to indicate condensation risk (fRSI), must be than, or equal to, 0.75 for residential buildings and this is comfortably met by incorporating the Isokorb.