A place in the country

18 January 2011

Oliver Chapman Architects chose timber frame for a range of social housing that is sympathetic to is rural setting in the Scottish Borders. Peter Wilson reports

Timber frame construction has taken a bit of a beating recently, at least if you read the more sensationalist news pages of the UK’s construction industry press.

True, there have been some spectacular fires in the London area over the last year or two, but to damn a whole – and otherwise successful industry – on the basis of conflagrations in incomplete and unoccupied constructions on unattended building sites is to deny the long experience that exists outside of our largest metropolitan area in the assembly of timber-framed buildings.

In Scotland, for example, the now infamous 1983 World in Action programme, which until relatively recently largely killed off timber frame in England, did not affect the method’s popularity as the ever-changing weather north of the border makes speedy assembly of walls and roof a housebuilding prerequisite. The effect of this has not only been a 25-year-plus track record of timber frame construction in Scotland but, with buildings up to seven storeys high built regularly and safely, more than 70% of its newbuild housing is formed by this very efficient method.

Not that you would know it, because much of this housing is clad in other materials ranging through brick and render to composite panels or metal sheet. This is not to deny the existence of timber, but merely to respond to market imperatives, local cultural and climatic conditions and increasingly stringent building standards for thermal performance, airtightness and fire.

Affordable housing
The issue is not about whether to build with timber or not – in Scotland it is nowadays virtually a given – but how to create well-constructed housing that is likely to last a long time, two factors high on the country’s large housing association sector wish list, tasked as it increasingly is with delivering political requirements for affordable housing.

Much of this category of accommodation is inevitably to be found in larger urban areas, but the demand is perhaps even stronger in rural locations where job opportunities are limited and wages are low. And with more than 40% of its population living in communities of 20,000 people or fewer, Scotland’s need for exemplary affordable rural housing models is constant.

Which brings us to the Scottish Borders, an area of relatively low population but with very distinctive housing needs. At Todlaw on the edge of Duns (pop.10,000), Edinburgh-based Oliver Chapman Architects have been working for several years with Berwickshire Housing Association to deliver a series of newbuild projects designed to meet a variety of community needs. The first of these – a pair of semi-detached houses – won the Scottish Design Awards Best Affordable Housing design prize in 2006. Since then the practice has gained three further commissions from this client, a significant vote of confidence for a young office and one that now sees the RIBA Regional Award-winning supported housing scheme it completed at Todlaw in 2008 complemented by a £1m second phase development of 12 flats arranged in three blocks of four. This ‘four in a block’ typology is not always associated with quality housing, and it is to the practice’s credit that it has elected to reinterpret a form with strong associations with between- and post-war social housing provision.

In this instance, the previous phase of single-storey supported housing established the palette of simple forms, eaves details and materials to be used, but here each of these has been taken to a subtler next stage.

Siberian larch
Where fibre cement slates had formerly been used for roof and walls to complement vertical larch cladding, the new development sports dark blue engineering bricks on those exteriors that face the open landscape, while softer, more homely shells of Siberian larch cladding implicitly connect the project to its predecessor on the other side of the street.

These brick and timber surfaces are visually separated by the external stairs, while the cladding itself is meticulously detailed – the board-on-board arrangement uses 100mm rear boards and 70mm front boards and incorporates a horizontal ‘stitch’ to the inner layer to resolve the ventilation/fire-stop requirement at first floor level. Tongue and groove boards are used to form the soffits of the porch canopies as well as the side linings to the external stairs. Colour too, connects this new phase of building with its predecessor, with wood ash (grey), storm (olive), green and charcoal stains from the Vaalti range providing a crisp, but subdued finish to the timber on the three blocks.

This is very deliberately not an ‘all-singing, all-dancing’ approach to architecture, but one that seeks to find its place – and to create one – within the given context. There are many subtleties to the design: gaps between gables allow views of Berwickshire’s agricultural landscape; there are private gardens to both front (for the upper flats) and back (for the lower) with living rooms facing onto each residence’s respective garden area. Similarly, kitchen windows look along the paths (lower flats) or down the stairs (upper ones). Cars are screened between the gables and are pushed to the rear boundary of the site.

But back for a moment to the structure of the three buildings. Yes, each block has a 150x50mm timber frame, heavily insulated with mineral wool and with a drylining system used in conjunction with 220x50mm timber joists to form the separating floors and walls. And as with so many of Scotland’s timber frame homes, the offsite manufacture of the structural frames and roof trusses (150x50mm) was carried out locally, in this instance in Hawick by James Swinton Ltd who were also the main contractors for the project.

The project eschews the eco-bling of Code for Sustainable Homes levels 5 and 6, but these requirements are not demanded in Scotland anyway. In this context, however, Robert Browning’s aphorism about great men might just as easily be applied to buildings, viz. “no more great buildings, dear God, just raise the general standard”, for at Todlaw, Oliver Chapman Architects have clearly been confident enough in their own abilities to do just that and to set a marker down for others to emulate.

The second phase of the Todlaw development features 12 flats arranged in three blocks of four
The brick and timber surfaces are visually separated by the external stairs
The larch cladding is arranged board-on-board – the rear boards are 100mm while the front are 70mm