The development of a new garden city on former MOD land at Bicester, Oxfordshire, is including a large number of homes built and certified to Passivhaus standard, with the specialist company involved making extensive use of Magply boards for three separate roles.
At the Graven Hill site, which is set to deliver 1,900 new dwellings, Beattie Passive offers a unique timber framed solution to achieving the very low energy performance required. It has established a “Flying Factory” onsite to fabricate panels and modules for the various property types, including terraces, while the detached coach houses are being stick-built.
One of these, Plot 101, which is nearing structural completion now, will feature two bedrooms, flexible living spaces and an integral garage behind its rendered elevations. The 9mm Magply boards, supplied have been specified to offer 90 minutes fire resistance as well as racking strength, acoustic insulation and also as the render backing board.
As a key partner at Graven Hill, Beattie Passive is set to complete around 50 units this year, both selling direct to the development company and offering a three level service for self-builders. These start at a design and technical support level, progressing to the construction of a weathertight and airtight exterior envelope or the turnkey handover of a fully custom built home.
The Senior Project Manager for Beattie Passive, Benedict O’Halloran commented: “So far at Graven Hill we have used the stick-build method for the small coach house units, while the terraced are panel. We are now about to start work on some detached units which will be modular, but all of them use Magply boards for their racking strength, acoustic performance and fire resistance.
“We use the 9mm Magply on the actual frame to provide rigidity, because the product has got such good racking strength. Then it is also specified for its sound absorption and fire resisting qualities. Independent tests carried out by Exova at Warrington have shown a figure of one hour 49 minutes for one side of a party construction.
“Another layer of 9mm Magply is also fixed across the inner face of the timber frame, followed by 25mm battens and plasterboard to create a service space and for the first time on this project we have also selected Magply – in conjunction with sub-contractor enviroREND – to be the render backing board for the exterior finish.”
The Site Agent for enviroREND, Rob Pearson added: “We fix the first layer of 9mm Magply before Beattie’s operatives apply their breather membrane then we install 25mm battens and another 9mm layer, which is then treated with the Baumit primer and the rest of the Baumit system.”
“The total thickness of 6-8mm features a basecoat with an embedded reinforcement mesh, another primer coat and then a white 1.5 mm silicone top coat. The installation process at Graven Hill has gone very well and as a company we are now going to be using Magply for all of our boarded systems in the future as it provides such a good substrate.
Despite offering good adhesion for the decorative render system, Magply boards are very moisture resistant thanks to their modified MgO formulation that also represents an environmentally friendly alternative to conventional plywood or OSB alternatives. The production process keeps the chlorine content to just 0.01%, enhancing long term durability, while Magply boards carry all the necessary, internationally recognised accreditations.