As a key sponsor of the Great British Refurb campaign, Knauf Insulation has supplied its Internal Wall Insulation System (IWI), as well as loft and floor insulation products, to the winner of the Grand Designs ‘Home of the Future’ competition.
Homeowner William Homoky, from Bristol, was chosen from more than 8,000 entries to receive the £23,000 whole house eco-refurbishment, which was delivered by Knauf Insulation in partnership with Keepmoat, a leading community regeneration specialist.
The project included the installation of IWI, suspended timber floor insulation on the ground floor, upgrading of loft insulation and major draft proofing, as well as installation of solar photovoltaic panels within the roof. The whole refurbishment has successfully led to 73 per cent reduction in energy use, 85 per cent reduction in carbon emissions and 123 per cent reduction in energy bills, enabling William to sell surplus electricity back to the grid in line with the Government’s feed-in tariffs.
David Cartwright of Keepmoat was Site Manger on the project, he said: “There are plenty of simple steps that can be taken to improve energy efficiency levels and reduce carbon emissions, in any type of property. However, with the majority of heat excaping through a building’s external fabric, efficient insulation levels are required to maxmise energy efficiencies and reduce heating bills in the long run – a desirable outcome of the Bristol project.”
The use of Knauf Insulation’s IWI system was key to eliminating the thermal bridging issue associated with systems incorporating timber and metal studs, making it almost 13 per cent more thermally efficient than traditional systems of the same thickness. In addition, the IWI system incorporates highly sustainable and recyclable glass mineral wool insulation achieving a maximum A+ rating in the BRE Green Guide to Specification and a Euroclass A1 fire rating to BS EN 13501: Part 1.
To increase thermal efficiencies 150mm of Knauf Insulation’s IWI system, EcoStuds and EcoBatts, were installed into the Bristol property providing a U-value of 0.20. The Knauf Insulation IWI system comprises EcoStuds - extruded polystyrene laminated to Oriented Strand Board (OSB), which are mechanically fixed to the internal wall. Earthwool EcoBatt water repellent, high performance, 75mm thick glass mineral wool slabs are friction fitted between the EcoStuds and faced with a vapour check plasterboard sheet. Earthwool EcoBatts fully fill the insulation zone and are in intimate contact with the EcoStuds and plasterboard, thereby preventing any air or draught movement through the system.
Cold bridging and surface condensation is then minimised by fitting 27mm of Polyfoam Linerboard, a laminate of 17.5mm extruded polystyrene and 9.5mm plasterboard around all window and door reveals. Polyfoam Linerboard (27mm) is also installed at all party wall junctions to a minimum width of 400mm and the full height of the rooms, in order to prevent heat loss and the potential for condensation and mould growth in internal corners.
The simplicity of the IWI system allows a competent builder to install and finish the system using a traditional plaster skim finish or dry lining techniques. No scaffolding is required and the system can be installed on a room-by-room basis, or as part of a whole house refurbishment, as seen in this particular project.
Homeowner William commented: “The refurbishment has been a quick and simple process – so much so, we've already begun recommending IWI to friends and family. The combination of comprehensive insulation and the solar photovoltaic panels means we are benefiting from a warmer, more energy efficient home and vastly reduced energy bills.”