Stewart Milne Timber Systems (SMTS) aims to supply timber frame houses achieving level 4 of the government’s Code for Sustainable Homes (CSH) without renewable energy technology, such as solar panels.
The company revealed its plans following exhaustive evaluation by its own technicians and Oxford Brookes University researchers of its hi-tech Sigma timber frame house at the BRE’s Innovation Park near Watford.
“A family lived in it for two weeks in each season and we constantly monitored every aspect of the interior conditions,” said Stewart Dalgarno, Milne Group product development director. “We recorded half a million pieces of data, making it one of the most detailed studies of its kind.”
The conclusion was that the key focus of the next generation of energy-efficient timber frame homes capable of meeting higher levels of the CSH has to be on the thermal performance of the building envelope. They also have to be easy to live with.
“The original Sigma house lost 40% more energy than anticipated, largely due to airtightness issues,” said Mr Dalgarno. “And the family found the control systems, and particularly the renewable energy technology, too complex.”
The maxim of the Sigma II concept that has resulted from the research is KISS – “keep it simple stupid”. The multi-layer wall structure of the original building is replaced with expanded polystyrene insulation-filled closed panels based on the Scandinavian ‘space stud’ system which minimises cold bridging. Airtightness is further improved by factory pre-fitting windows and the building is finished in a brick skin.
“By focusing on the envelope we’re providing a fit and forget solution,” said Mr Dalgarno.
Milne, he added, was now piloting the new approach with a registered social landlord which should lead to Code level 4, renewables-free houses going on site within 18 months.
Mr Dalgarno confirmed that the UK construction slump had led to redundancies at STMS, but said it was maintaining production at both its Aberdeen and Witney sites.
