An external wall insulation system manufactured by Sto has helped to renovate historic hangar buildings at Pembroke Dock in Wales. Architects Purcell specified Sto to upgrade annexes connected to two hangars, allowing them to be transformed into new office and workshop spaces. One of the annexes required a two-storey extension and the other had to be rebuilt. For both projects, the StoTherm Mineral M external wall insulation system was selected with a Sto render façade finish, and includes mineral fibre insulation boards providing a high level of fire protection and thermal performance.
Main contractor R & M Williams fixed the insulation boards to cement particle boards, installed to the light-streel frame structure, with Sto-Rotofix Plus mechanical fixings. These unique, helical spiral fixings can overcome the problems of variable cavity requirements, as the position of all the fixings can be viewed during installation and they can easily be adjusted to achieve correct alignment of the insulation boards. A 20mm drained cavity behind the insulation boards was created for this project allowing any excess moisture to drain out of the bottom of the system, meeting the requirements of NHBC Building Control. As first-time installers of Sto’s products, R&M Williams attended a system application demonstration prior to commencing the installation.
“Although we have vast experience of installing external wall insulation, we hadn’t worked with Sto’s systems before and wanted to bring that expertise in house,” explained Jack Jones, Senior Quantity Surveyor at R&M Williams. “This saw several members of our team take part in Sto’s system demonstration, including how to install the insulation boards using their unique Sto-Rotofix fixings”. Jack continued: “Once on site, we also benefited from Sto’s extensive technical support which covered all bases. Any questions we had were either answered swiftly over the phone or a representative would come to site to help us.”
As a heritage site, it was vital the extended annexe and new structure complemented the existing buildings. Sto’s extensive StoColor system enabled the façade of the new annexe to be finished in a blue resin StoSilco K1.5 render to match the colour specified by and signed off by the conservation officer. For the extension, the render was colour matched to the existing lime render. StoColor Silco G silicone resin façade paint, applied as a final finish to the Sto render, has also provided high levels of water repellence and resistance to algae and fungus growth, which is essential given the hangars’ close proximity to the sea. Further detailing was achieved thanks to StoDeco
Profiles which were installed above and below the windows to emulate stone lintels. Manufactured from Verolith, which comprises 90 per cent perlite, StoDeco profiles are highly resistant to weather, light in weight, quick to install and form a durable bond with the render.
Jack added: “This was a very complex project due to the historic nature of the site, its coastal location and the need to install a new external wall insulation system on buildings of different ages. Despite these challenges, the project was completed successfully. We’ve been very impressed by Sto’s technical support throughout as well as the quality of its products.”
Claire Lawrence, Project Manager at the Port of Milford Haven added: “The improvements made to the Hangar Annexes, including the works undertaken by Sto on the external wall insulation system, at Pembroke Port have made them into flexible modern workspaces that are ideal for the renewable energy industry here in Pembrokeshire. The works completed were done to very high standards, the buildings are very impressive and are ready for tenants.”
Led by the Port of Milford Haven, the new development is funded by the Swansea Bay City Deal, the European Regional Development Fund through the Welsh Government and through private investment. The development aims to create a world-class centre for marine energy and engineering close to the Celtic Sea. www.sto.co.uk
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