HAMPSHIRE
CASE STUDY
A
husband-and-wife design team comprising an engineer and an architect surpassed their original goal of creating a low energy new build near the Hampshire coastline when their home comfortably qualified for passive house certification. The joint expertise of architect Ruth Butler and engineer Julian Sutherland in sustainable design meant that their house required only a few tweaks to the original plan to get it over the line. In the end, they sailed past the passive house standard. And while Ruth calculated that building to the benchmark added 7.4% over building regulations onto the cost, it has proved life changing. Based out of her home office since 2015, Ruth has grown her architectural practice locally and designed three passive houses. Meanwhile, Julian qualified as a passive house designer through his work on the property. “We originally wrote ourselves a low energy brief focused on lots of insulation and airtightness, but we didn’t intend to build a passive house. Then when we tested it against passive house — not expecting it to be close — we realised if we put in more high-performing triple glazed windows, we could achieve it,” said Ruth. “As we no longer needed underfloor heating, we could spend that money on the windows.” The couple met while they were both working on the development of tennis court number one at Wimbledon in the mid-nineties. Over the years, in their respective careers, both Ruth and Julian have had a keen interest in low energy design. In London, they lived in a 1960s townhouse, but wanted to use their complimentary expertise to create a low energy house on the south coast. Ruth took charge of the design, while Julian did the passive house calculations. As an engineer in building services, he understood all about airtightness, insulation and ventilation. “The calculations showed it was outperforming expectations. But we actually did a lot of things over and above the passive house standard, such as using low embodied carbon materials and reducing water usage. We also avoided plastering all the walls,” he says. “Laying natural quarry tiles on the floors helped make it a dry building site and we used zero VOC [volatile organic compound] paint. I supervised the insulation to make sure there were no gaps or bad junctions, and we achieved 0.55 air changes.” The original desire to move out of London with their daughter — who is now 14 — to settle on the south coast was partly motivated by the family’s passion for sailing. Rather than travelling all the way out to the seaside and back to London at weekends, they wanted to live minutes from the sea. The couple bought a different site initially, but planning limitations spoiled their plans so they sold it on. They used the profit to fund the purchase of the brownfield site, in Emsworth, Hampshire, which was previously owned by St John’s Ambulance.
34 | passivehouseplus.co.uk | issue 33
