Wilmcote House – High rise refurbishment sets new standard
The comprehensive refurbishment of a Portsmouth high rise residential block containing 107 homes is underway in a project carried out with the residents in situ, in a landmark scheme which, once complete, will be the first large scale project in the UK reaching the EnerPHit standard.
The project, being carried out for Portsmouth City Council, is transforming Wilmcote House on the Somerstown Housing Estate and was designed by ECD Architects, with Keepmoat Regeneration as the main contractor; Carter Clack as structural engineers and Keegans Ltd as quantity surveyors.
Achieving EnerPHit – the Passivhaus Certificate for retrofits – means that significant energy savings of between 75 and 90 % can be achieved – even in existing buildings.
Steve Groves of Portsmouth City Council said: “This major retrofit scheme is Portsmouth City Council’s biggest housing project to date and also represents a new approach to refurbishment. The adoption of Passivhaus principles could see it used as a model for sustainable retrofit across the UK and Europe. This is a very complex scheme from a construction point of view, especially as the works are being carried out with the residents in occupation.
The project is expected to extend the life of the building for a minimum of 30 years, providing a sustainable approach for the estate’s regeneration, significantly reduce heat loss/energy use and fuel poverty for residents, as well as contributing to the Somerstown area-wide regeneration.
Wilmcote House, which incorporates 100 three bedroom maisonettes and seven one-bedroom flats, was constructed in 1968 and is an 11 storey large panel ‘Bison’ REEMA concrete construction building, where a number of major elements were coming to the end of their serviceable life.
The scheme comprises external works including: complete overcladding of the structure with a Rockwool system, overlaid with either a rendered finish or cladding panels to insulate the building; installing new triple glazed windows; complete re-roofing, together with new roof insulation; enclosing communal walkways; carrying out concrete repairs and re-decoration of external communal areas, as well as creating an additional entrance and introducing restrictive access doors.
Internal works include installing a new mechanical ventilation heat recovery system; new electric heating, installing new hot water cylinders and electric showers; extending living areas; creating a sun room and converting a former housing office within the building into four additional flats.
Steve Groves said: “The building as it was, was cold and damp suffering from condensation and water ingress, and the lack of insulation meant high fuel costs for residents.
“It is now being insulated to a level above and beyond the current building regulations. An important element required for achieving the Passivhaus certificate is also to ensure that the structure is airtight. The large panel concrete construction limits the type of heating that can be installed to electric only, however it is envisaged that the exceptional level of insulation will still considerably cut fuel costs for residents.”
The project is well underway, with completion due in March 2017.