An online discussion hosted by Schueco UK and Architecture Today explored the motivations and processes behind the recent renovation of self-built houses by architects Sarah Wigglesworth and Piers Taylor
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The process of renovating or adapting these houses provides an opportunity to reflect on the consequences of the original design decisions, and architectural decision-making in general. How, for example, does one’s taste or priorities change over time? And what is the best approach to specification as materials and building knowledge continually improve?
House on Stock Orchard Street by Sarah Wigglesworth Architects (ph: Paul Smoothy)
Completed in 1997, Sarah Wigglesworth’s house on Stock Orchard Street in north London pioneered new construction techniques to create a sustainable, urban live-work space. More than 20 years later Wigglesworth decided to embark on a major retrofit project that would not only make the dwelling more energy-efficient, but also ensure that it remains comfortable and safe as its occupants grow older.
While the house represented the cutting-edge of sustainable design when it was built, the green building movement “has changed quite a bit in the last 25 years”, said Wigglesworth. “The focus is now on energy consumption, energy-in-use, Passivhaus techniques, and environmental modeling to predict future energy performance”. Taking advantage of the progress made in energy analysis, Wigglesworth commissioned a full environmental audit – the aim being to “bridge the performance gap between 1997 and 2020”.
The process, which included thermal imaging, energy modeling, airtightness and ventilation evaluation, building fabric analysis, and U-value calculations, has informed a series of fabric and servicing upgrades. Among these are improved airtightness throughout, additional insulation to eliminate thermal bridging, weatherstrips to existing doors and windows, existing rooflights replaced with thermally-efficient models, and an upgraded MVHR system with all existing pipes and ductwork cleaned.
In terms of age-related improvements, the architect has implemented level thresholds, designated spaces for a future carer and lift, installed grab rails on the staircase and in the bathroom, made safety adjustments to the kitchen, upgraded the lighting, and generally improved comfort levels throughout the dwelling.
Moonshine by Piers Taylor (ph: Jim Stephenson)
Built almost exactly 20 years ago, Piers Taylor’s house, Moonshine, reflected the architect’s design preoccupations of the time – namely an expressive and largely exposed timber-frame structure, as well as high levels of glazing to promote daylighting and views out across its rural setting, in a valley near Bath.
When you’re young and you build, you invest a lot of emotion in the process. Living in the house and seeing my own naive and youthful architectural moves and preoccupations on a daily basis came to torment me. It was a constant reminder of how little I knew, and how my values had changed”
Taylor readily admits that his relative inexperience, particularly in working with timber, led to a series of flaws with both the structure and fabric. Chief among these were issue of weather penetration as the green oak frame dried out and then shrank. Added to this, were issues of solar gain – caused by the death of large ash tree that previously shaded the predominantly glazed structure – and low thermal performance caused by inadequate insulation and thermal bridging.
“When you’re young and you build, you invest a lot of emotion in the process”, recounted Taylor. “Living in the house and seeing my own naive and youthful architectural moves and preoccupations on a daily basis came to torment me. It was a constant reminder of how little I knew, and how my values had changed.” It was during this time that Taylor purchased some woodland near the house and proceeded to build a barn, studio and toilet block. “We developed a way of building with timber that is both economic and efficient”, recalled the architect. “The new structures are built to benefit from the way timber shrinks, making them stronger while also retaining weather-tightness.”
Armed with greater knowledge and practical experience, Taylor decided to retrofit the house, which he had “come to hate”. Central to project has been to wrap the existing structure in a ‘duvet’ of insulation (up to 450mm-thick in places), while reducing the size of the windows, adding two membranes to the walls and installing a roof-mounted PV system to power electric underfloor heating. “Renewing the house has been less about falling back in love with the physical building, and more about falling in love with the wider landscape; the views, the tress, the weather and the surrounding context”, explained Taylor, who concluded his presentation with typical honesty: “It’s a joy to know that the house is well built and works – finally!”