Fraser/Livingstone Architects has combined strong acoustic performance, sustainable design and aesthetic success in six CLT-framed apartments in Edinburgh
Once a common sight in Edinburgh, late 16th and 17th century timber framed buildings are now few and far between. Most have been demolished, with only fragments to be found behind rendered facades on Lawnmarket, in the city’s Old Town. However, the bid to cut carbon emissions has seen a timber renaissance, spearheaded by Fraser/Livingston Architects – whose project Simon Square has greatly improved the acoustic properties of cross laminated timber, bringing it into line with the country’s stringent technical guidance.
This contemporary tenement is Scotland’s first developer-led cross laminated timber building. It is tightly nestled between two storey pink pebbledash terraced flats on one side and a 1930s four storey stone clad tenement on the other. The practice has built six new flats – five with one bedroom each and a two-bedroom duplex on the upper two storeys – achieving maximum value for the developer without compromising quality. Four of the apartments are equipped with juliet balconies, while the duplex comes with a rooftop garden and the ground floor flat has its own small outdoor space.
‘Given the constrained site and proximity to the neighbouring building, getting it past planning was the biggest challenge,’ explains lead architect Ayla Riome. Before approaching the practice the developer had worked with another architect whose designs failed at planning stage.
To satisfy the planners, Fraser/Livingston designed a chamfered rear elevation to avoid overlooking. This serrated form echoes a staggered row of Victorian bay windows. Softer chamfering is used on the street-facing facade to create a sheltered entrance.
At the rear of the site the original 4m boundary wall has been lowered to 2m, allowing more light to reach both the new homes and neighbouring buildings. The flats are accessed from a communal stair, with the power used in the shared area sourced from solar PV panels.
Interiors are warmed and brightened by exposed timber and generously-sized windows – which is greatly needed in the dreich city. Although buyers were given the option of whitewashing the timber, none chose to do so. When asked about their experience living in the new flat, one resident commented: ‘I like it, the exposed timber reminds me of a cabin or ski chalet and the windows, compared to the flat we were in before, are glorious.’ They also remarked that during the summer heatwave the flat ‘felt like a greenhouse’ but acquiesced that so far their energy bills have been remarkably low and are fairly confident that their new homes will help them weather the inflated energy bills hitting the nation.
Externally, the CLT structure is clad in brick, with white lime ‘slaister’ render, giving the building a satisfying, monolithic solidity that echoes the stone tenements of Edinburgh. Central to the design is the question of how the high density achieved by the stone tenements can be continued in an innovative sustainable way. Malcolm Fraser, who sits on the Mass Timber Alliance, believes timber is the structural material of the future, but advocates for the use of CLT rather than thin engineered timber coated in toxic treatments.
Timber may be sustainable in materiality, but it is less so for its air miles
He points out that due to the country’s high acoustic control requirements – which demand a 56dB reduction in noise, much higher than England’s and one of the highest in Europe – CLT used in housing is often concealed behind plasterboard which results in a loss of the material’s tactile qualities. The practice has used exposed timber in previous projects, such as the Arcadia Nursery and Edinburgh Climate Change Institute, and is experienced in its benefits, citing research undertaken in Austria which has shown that exposed timber interiors can lower heart rates, contributing to a calming environment. Through the use of acoustic wall hangers, wood fibre insulation and plasterboard in the ceiling only, Fraser/Livingstone has managed to exceed these already-high acoustic standards by 6dB. That allows the timber, that residents are so fond of, to remain exposed.
This is an important development in the use of CLT, but more needs to be done. Although Scotland has the largest area of woodland in the UK, with a total of 1.34 million ha – of which only 737,000 ha are FSC certified – more than 90% of the timber used in Scottish construction is imported European softwood. And as Scotland has no CLT manufacturers, the timber used in this project was also imported from Europe. So timber may be sustainable in its materiality, but it looks a lot less so when its air miles are taken into account.
Added to that, the industry still has a lot to learn about the material, and few contractors are very experienced with using CLT at such a large scale. Meanwhile, the Mass Timber Alliance is working to improve this by supporting the development and availability of standard test data on the material. As we work towards creating a more sustainable industry, Simon Square is an important precedent for reimagining the vernacular in a sustainable, inventive way in the developer-led market.
Gross internal floor area 425m²
Gross internal + external floor area 520m²
Approx construction cost £1.2m
Construction cost £2307/m²
Architect Fraser/Livingstone Architects
Client Seven Hills Investment
Structural engineer Elliot & Company Consulting Engineers
M&E consultant Harley Haddow
QS David Adamson Group
Acoustic consultant Robin Mackenzie Partnership
Main contractor True Build
Principal designer David Adamson Group
CLT supplier Egoin Wood Group (CLT Supplier)