Isle of Man gets First BREEAM Excellent Rating with Tradical® Hemcrete®

Merging several of its departments to become the Department of Environment, Food and Agriculture, the Isle of Man Government wanted a supremely green building for its new headquarters, named Thie Slieau Whallian. Key to this was low carbon construction and the attainment of the island’s first BREEAM Excellent rating. To do this, Lime Technology’s innovative hemp based concrete substitute – Tradical® Hemcrete® – was specified.

Designed by Ashley Pettit Architects for an occupancy of 70 plus members, the building was created with the best of environmental construction in mind to reflect the work of the newly formed Department of Environment, Food and Agriculture. It features natural ventilation and lighting and a biomass boiler, fed by the department’s own sawmills, to keep energy use down. Tradical® Hemcrete® was vital in supporting the biomass boiler through its superb thermal efficiency and ensuring a healthy environment for staff.

Thie Slieau Whallian was built by main contractors Auldyn Construction Ltd. The bulk of the building was constructed with timber framing and panels with all cavities filled with high performance insulation of recycled paper. Tradical® Hemcrete® was used to create a curvilinear wall 500mm thick at the public entrance of the building.

Ideal for use in green projects, Tradical® Hemcrete® is a mix of hemp and a lime binder, which together create a material that combines sustainability with performance. The product absorbs CO2 in its manufacture (hemp, in common with all similar plants, captures carbon dioxide during its rapid growth and releases oxygen back out to the atmosphere) so has negative embodied CO2. For a typical wall section, Tradical® Hemcrete® will have 130kg CO2/m² less than traditional brick and block.

The product is highly insulating resulting in walls with a very low U value, ideal for meeting the higher levels of the Code for Sustainable Homes. It also has excellent thermal inertia (similar to thermal mass) and as such, houses built of Tradical® Hemcrete® change temperature very slowly, which helps to reduce heating loads to significantly below that of lighter weight buildings with the same U value.

The use of Tradical® Hemcrete® in the entrance atrium had two main purposes. Primarily, it would increase the thermal mass of the building. As Tradical® Hemcrete® stores heat during the day to release it at night, it was ideal for such a specification. As the atrium was also the central location for the circulation of air as part of the building’s natural ventilation, it would also ensure a healthy environment.

Now complete, the superb thermal efficiency of the Thie Slieau Whallian building is a key feature of the Isle of Man’s built environment. Fitting into its rural setting perfectly and reflecting the ideals of the Department for Environment, Food and Agriculture, it is a prime example of the capacities of sustainable construction. The use of Tradical® Hemcrete® on such a scheme illustrates its potential for the most cutting edge sustainable projects.

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