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On-demand webinar: One-off house design

Ruth Slavid

On 3 November 2020 RIBAJ and PiP were joined by a group of architects to discuss a range of private home and extension projects and how the pandemic is changing what we want from our properties

In the past few months there has been an unexpected rise in private house and home extension projects as people try to lockdown-proof their homes. This webinar on the design of such one-off projects, features the architects of award-winning schemes, plus the author of the recently published book, How to Extend your Victorian Terraced House.

If you missed it, catch up with the video here. Speakers at the event were:

Jacqueline Green of Green & Teggin Architects in conversation with Helen Castle, publishing director of the RIBA Journal. Discussing her recently published book How to Extend your Victorian Terraced House and the key pointers to consider when embarking on a conservation project of this nature.

Greg Lomas (founder and practice director, Foster Lomas Architects) presenting his practice's rural retreat project on Sartfell, a peak on the Isle of Man.

Nicolo Stassano (founder, Studio Stassano) discussing the case study of Blenheim Road, a Grade II listed, Regency period, semi-detached end-of-terrace house in London's St John’s Wood Conservation Area.

Percy Weston (co-founder, Surman Weston) showcasing the practice's private house project located in suburbia that evokes the spirit of California with industrial inspiration.

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In some ways homes are all alike, satisfying our needs for shelter and security, for somewhere to eat and sleep, to wash and to relax. But they are also among the most diverse of building types and, as many architects will acknowledge, the most challenging. A home has to fulfil so many functions and all in a relatively small space and, however expensive it may seem, to a limited budget.

All these points were brought home (!!) by the PiP webinar on homes at the start of November. Jacqueline Green of Green & Teggin Architects is the author of the recently published How to Extend Your Victorian Terraced House. Since the pandemic hit, she said, enquiries to her practice have risen. She was already, she said, seeing a shift towards requirements for home work spaces and, in particular, for garden rooms. Now, she said, this is accelerating.

Green’s book details numerous ways of enlarging Victorian houses. The essentials, she said, are addressing circulation, since this can be wasted space, and ensuring that you bring in enough light to buildings that, typically, have a deep plan even before extension. Some of her approaches include putting the rooms that don’t need natural light (typically bathrooms, utilities and even kitchens) into the deeper areas of the plan and extending outward into the garden rather than filling in the side return. This retained space can then act as a courtyard bringing in light.

The other speakers described three very different individual houses. Greg Lomas of Foster Lomas explained how the rural retreat that he designed for a couple at Sartfell on the Isle of Man was not just a home, but also at the heart of a nature reserve that they were creating. On a site next to one of the traditional white cottages of the area, the new house was attached to the old as planning permission was only available for an extension. Once complete, the two houses were separated, with the old one providing guest accommodation.

The new house is very different. Partly buried in the ground, it is clad in rough dark stone intended to weather and be colonised by local flora. The owners are keen ornithologists and the views from the windows are paramount. A perforated stair allows light to filter down through the three storeys, which include a ‘knowledge centre’ (a library/collection of bookshelves) and a workspace.

Lomas explained challenges that included the extremely windy conditions of the hillside position and the need to protect the insulation from attack by insects. Internally, surfaces are deliberately hard, with polished concrete floors. The architect is now designing a visitor centre on the same site.

Extending a Grade II-listed early Victorian semi-detached house in London’s St John’s Wood could not be a more different proposition. Nicolo Stassano of Studio Stassano explained the process of designing a basement that not only provided extra space, but also allowed a rearrangement of other areas in the house. He explained how the design changed through the development and planning process, reducing a rear extension in size to provide a more rational response to the root zones of protected trees. 

Adding an extra storey as part of the replacement of an existing side extension was contentious at planning stage, Stassano said. He won the battle because it matched the height of an existing extension on the other house of the pair.

The roof of the rear extension was a challenge. ‘All rear extension roofs are difficult,’ he said. ‘You are limited in depth and level.’ And, he warned, ‘building a basement is a large exercise. The amount of steelwork and structure required is incredible.’

The secret to a successful basement design, Stassano said, relies on the places where it extends beyond the original footprint, because that is where it is possible to put in lightwells and so bring light into a potentially dark space. His rooflights were half glass and half grille, forming a vital part of the ventilation strategy.

Looking at the finished house, the casual observer might not realise just how much work and complexity had been involved. And the same would be true of the final case study, Ditton Hill House in Surbiton, designed by Surman Weston. While the house, particularly from the front, has a beguiling apparent simplicity it is actually hugely complex both in the spatial thinking and in the detailing needed to build it successfully.

Percy Weston of Surman Weston explained the thinking that was necessary to allow the use of the external steel skeleton that makes a subtle reference to half-timbered houses in the neighbourhood. It was vital to maintain thermal integrity and Weston explained that this was done by designating every element in the building as either ‘cold’ or ‘warm’ and creating a special detail between them that ensured that there was a thermal break.

In addition, every external brick panel has a mastic joint with the steel to accommodate the differential expansion of brick and steel.

This house is an architectural tour de force, albeit on a relatively modest scale. Hearing an architect explaining not only their design principles but also the details of how they made them reality is the special value of these webinars.

Ruth Slavid is an architectural writer, editor and consultant.