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Innovative school chooses Thermalite over timberframe


The new Technology Centre at Thorpe St Andrews School in Norwich will be the focus of the school's vision for innovative education in design and technology. It will also be available for other schools and learning groups to use. Designed by NPS Property Consultants Ltd, the single-storey pavilion building began on site in November 2006, with Hanson Building Products providing a cost-effective and sustainable solution to the construction in the form of its Thermalite Turbo blocks and Thin Joint Mortar.

“We examined a number of construction methods, including timber frame,” comments Paul McLaren of NPS Property Consultants Ltd. “We concluded that Thermalite aircrete blocks with Thin Joint Mortar best met our requirements. Influencing factors were the speed of build, the light weight of the blocks and the excellent thermal resistance offered, which met the demand to comply with an environmentally-friendly construction ethic.”

The 300mm Turbo blocks have been specified for the foundations and the external walls, with 100mm and 140mm Shield also used in some areas. The Turbo blocks offer very high insulation properties, due to their unique formulation, making them ideal for external wall applications where low U values are required. As Thermalite's aircrete blocks are manufactured using pulverised fuel ash, a by-product from coal burning power stations, up to 80% recycled materials are used in production.

On site, aircrete blocks have a distinct advantage over comparable building materials with a micro cellular structure offering extremely high thermal insulation, and consequently, lower energy consumption for the heating and cooling of buildings. Lightweight properties and high dimensional tolerances minimise waste, and the blocks can be precisely cut to the correct sizing.

The use of Thin Joint Mortar is also proving a major benefit. This is a pre-mixed cement based mortar which, as an alternative to sand/cement mix mortar, allows the depth of the mortar to be vastly reduced. Thin Joint Mortar improves the thermal performance of external walls, minimising the heat loss through mortar joints, by reducing the volume of mortar required by at least 70% compared with traditional mortar.

NPS Property Consultants Ltd are working with T Gill & Sons as main contractors, with Jewson supplying the Thermalite product range. “As the team has already worked with Thermalite products in the past, this familiarity has also helped with the speed of build,” continues Paul McClaren. “Overall, the cost efficiency in terms of reduced materials and labour means that the Thermalite blocks with Thin Joint Mortar are proving to be a very competitive form of construction.”

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