AJ Specification 01.12 – Roofing and Drainage
Case studies of 23 Blackheath Park by Charles Barclay Architects, Holy Trinity Primary School by Architype Architects and Studio Lofts by Pott Architects
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Editorial - Felix Mara
Frank Lloyd Wright once said to a client who complained about roof water leaking overhead, ‘Why don’t you move your chair?’ Today it would be unwise to ignore the fact that a large proportion of claims against architects involve the ingress of water, so a fresh look at roofing and drainage might be a good place to start your CPD this year. This month’s Overview looks back at some of the highlights of roofing design last year, touching on retrofit projects, conservation and brown roofs. Our first case study, 23 Blackheath Park, where Charles Barclay Architects has restored and added to a London ‘tea caddy’ house, is particularly relevant because it involves three types of roof; one traditional, one extensive and one glass.
Our second case study, Architype’s expansion of Holy Trinity Primary School in Richmond upon Thames, provides a new entrance and accommodation for 210 additional pupils, with extensive green roofs and timber-clad inclined soffits that complement the finishes of the external walls. Although the roofs are flat, their covering continues over the rooflights and is therefore visible from ground level. At Studio Lofts in Hamburg, our final case study, Pott Architects has transformed a former industrial building complex into a centre for creative companies, with a flamboyant overhanging roof.
23 Blackheath Park, Blackheath, London by Charles Barclay Architects
23 Blackheath Park is a Grade II-listed ‘tea caddy’ house, built around 1820. The commission was to restore the house from bedsits to a family dwelling, taking advantage of a two-storey 1960s side extension, and to rebuild a span house in the garden as a guest house/garden room. The previous drive-through was converted into a new entrance hall and kitchen, with a glass rear extension as the new dining area. A master bathroom and balcony were created on the first floor of the side extension, with the double-height kitchen space behind, and a new stair and cross-axis to connect the entrance hall with the 19th century rooms. The new Outback is a single-storey pavilion, with a brick bedroom block and a living/garden room glazed to front and rear, giving a visual connection from the main formal garden to a grove of birch trees at the very rear.
Charles Barclay, director, Charles Barclay Architects
Holy Trinity Primary School, Richmond, London by Architype Architects
Architype’s design extends the existing 1970s primary school from 1FE to 2FE by integrating a series of new cross-laminated timber wings with the existing buildings. The expansion provides 12 new classrooms, group spaces, staff areas and a dedicated SEN facility. The existing school has been opened out into the landscape and a series of courtyard spaces has been created.
The timber roof panels cantilever to provide shade and a weather-protecting edge. Open cell insulation combines with the mass of the green roof system to acoustically insulate the building from high levels of aircraft noise.
The new wings are well-insulated and airtight with high performance triple glazed windows and mechanical heat recovery. An earth tube system cools the classrooms in summer and mitigates the potential future impact of climate change. Long-term maintenance and future disassembly have been considered through the specification of robust self-finished, modular and mechanically fixed components. Renewable bio-based products have been specified to minimise embodied CO2 and reduce potential toxicity within the internal environment.
James Todd, associate, Architype
Studio Lofts, Hamburg by Pott Architects
Between the city and the airport in the north of Hamburg, an existing industrial building complex has been transformed into a centre for emerging creative companies. The existing site, including the courtyard and nearby park have gained a new curtilage. The project aims to revitalise existing industrial space to create an ecological symbiosis of old and new.
Surrounded by a green park, a 7,000m2 courtyard ensemble has been redeveloped into a vivid mixed-use community with workyard, warehouses, media studios, café, dance studios and creative offices.
The sensitive transformation of the existing buildings and the addition of a new roof wing has revitalised the ensemble into flexible office spaces with a unique loft atmosphere. Our ecological and bio-climatic strategy involved using sustainable materials and a timber frame for all new construction. The orientation of the facades, with a glazed south elevation, provides high levels of solar energy gain.
The project addresses contemporary challenges, such as the need for innovative design of working environments, the redevelopment of shrinking cities and careful use of energy. Studio Lofts Hamburg provides space for new ideas, with flexible lofts that are able to respond to individual space requirements of young, dynamic companies.
Ingo Pott, director, Pott Architects