WANDSWORTH ROAD PROJECT
The site was a disused semi underground public lavatory that had been purchased from Lambeth Council in 2003.
The planning process was extremely protracted with consent eventually being granted on appeal in 2010.
The final design is for a single storey hexagonal building divided into three one-bedroom dwellings. It is constructed from structurally insulated panels with painted timber cladding. A sedum green roof was specified to improve it appearance from the much higher buildings surrounding and to reduce overheating in hot weather. The doors and fenestration were sourced from the Danish manufacturer, Velfac for their high insulation value and air tightness. Each flat has a Titon mechanical ventilation system with heat exchanger installed plus under floor heating and all the lighting is LED.
The construction phase started in August 2012 and was completed in February 2013. The prefabricated SIPs superstructure went up in nine days. A great deal of effort went into detailing to minimise cold bridging and maximise air tightness. External storage for bicycles and refuse was built into the building in the form of a bespoke galvanised steel frame. The timber cladding is Metsa ‘Thermowood’ which is much more resistant to rotting and warping than regular softwood.
When the building was tested for air tightness, it achieved an average rating of just 2.6m3/(h.m2). To put this in context, UK building regulations require a minimum of 10m3/(h.m2) and the Passivhaus standard is under 1m3/(h.m2).
The first tenant moved in at the beginning of March 2013 (the coldest March on record for the UK with sub zero temperatures for most of the month) and when I saw him at the beginning of April, he said that he had never felt any need to turn on the heating during this time.
Structural engineer: http://www.pddesign.co.uk
SIPs superstructure: http://www.glosford.co.uk
Green roof: http://happecontracts.co.uk
Corian kitchen worktops: http://www.isurfaces.co.uk
Storage frame and railings: http://www.jrsfabrication.co.uk